WO2024123716A1 - Kcnt1 inhibitors comprising a sulfonamide ring core and methods of use - Google Patents

Abstract

Disclosed herein are compounds comprising a sulfonamide core and pharmaceutically acceptable salts thereof, and compositions useful for preventing and/or treating a neurological disorder, a disorder associated with excessive neuronal excitability, or disorder associated with a gain-of-function mutation in a gene (e.g., KCNT1). Methods of treating a neurological disorder, a disorder associated with excessive neuronal excitability, or a disorder associated with gain-of-function mutation in a gene such as KCNT1 are also provided herein.

Description

KCNT1 INHIBITORS COMPRISING A SULFONAMIDE RING CORE AND METHODS

OF USE

Cross-Reference to Related Application

[01] This application claims the benefit of, and relies on the filing date of U.S. provisional application number 63/386,019, filed 5 December 2022, the entire disclosure of which is incorporated herein by reference.

Field of the Disclosure

[02] The present disclosure is generally directed to KCNT1 inhibitors comprising a sulfonamide core, as well as pharmaceutical compositions and methods of treatment involving the use of such compounds.

Background of the Disclosure

[03] Potassium sodium-activated channel subfamily T member 1 (“KCNT1”) is one of the genes in a family of genes responsible for providing the instructions to make potassium channels. KCNT1 encodes sodium -activated potassium channels known as Slack (Sequence like a calcium- activated K⁺ channel). These channels are found in neurons throughout the brain and can mediate a sodium-activated potassium current /KNa. This delayed outward current can regulate neuronal excitability and the rate of adaption in response to maintained stimulation. Abnormal Slack activity has been associated with development of early-onset epilepsies and intellectual impairment. Accordingly, pharmaceutical compounds that selectively regulate sodium-activated potassium channels, e.g., abnormal KCNT1 or abnormal /KNa, are useful in treating a neurological disease or disorder or a disease or condition related to excessive neuronal excitability and/or KCNT1 gain-of- function mutations.

Summary of the Disclosure

[04] Described herein are compounds and compositions useful for preventing and/or treating a disease, disorder, or condition, e.g., a neurological disorder, a disorder associated with excessive neuronal excitability, or a disorder associated with a gain-of-function mutation in a gene, for example, KCNT1.

[05] In one aspect, provided is a compound of Formula (III) having a sulfonamide core:

or a pharmaceutically acceptable salt thereof, wherein:

X is chosen from -C- or -N-;

Ri is chosen from -H or an alkyl;

R2 is chosen from -H, an alkyl, an alkoxy, or a halogen;

R3 is chosen from -H, an alkyl, or a halogen; and n is 1 or 2.

[06] In certain embodiments of the compound of Formula (III), X is -C-, and in certain embodiments, X is -N-. In certain embodiments of Formula (III), Ri is -H, and in certain embodiments, Ri is -CH3. In certain embodiments of Formula (III), X is -C-, n is 2 and Ri is -H, such that Formula (III) forms a benzothiazine dioxide. In certain embodiments, R2 is chosen from -H, - OCH3, or -F. In certain embodiments of Formula (III), R3 is -Cl. In certain embodiments of the compound of Formula (III), X is chosen from -C- or -N-; Ri is chosen from -H or an alkyl; R2 is chosen from -H, an alkoxy, or a halogen; R3 is a halogen; n is 1 or 2.

[07] In certain embodiments, the compound of Formula (III) having a sulfonamide core is chosen from:

[08] In one aspect, provided is a pharmaceutical composition comprising any of the compounds described herein, or a pharmaceutically acceptable salt thereof, and at least one pharmaceutically acceptable excipient.

[09] In one aspect, provided is a method of treating a neurological disorder, a disorder associated with excessive neuronal excitability, or a disorder associated with a gain-of-function mutation of a gene, comprising administering to a subject in need thereof an effective amount of any of the compounds described herein or a pharmaceutically acceptable salt thereof, or pharmaceutical compositions described herein comprising such compounds or a pharmaceutically acceptable salt thereof.

[010] In some embodiments, the method provided involves treating a disorder associated with a gain-of-function mutation of KCNT1.

[OH] In some variations, the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is epilepsy, an epilepsy syndrome, or an encephalopathy.

[012] In some variations, the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is a genetic or pediatric epilepsy or a genetic or pediatric epilepsy syndrome. [013] In some variations, the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is a cardiac dysfunction.

[014] In some variations, the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is chosen from epilepsy or other encephalopathies (e.g., malignant migrating focal seizures of infancy (MMFSI) or epilepsy of infancy with migrating focal seizures (EIMFS), autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), West syndrome, infantile spasms, epileptic encephalopathy, focal epilepsy, Ohtahara syndrome, developmental and epileptic encephalopathy, Lennox-Gastaut syndrome, seizures (e.g., Generalized tonic clonic seizures, Asymmetric Tonic Seizures), leukodystrophy, leukoencephalopathy, intellectual disability, Multifocal Epilepsy, Drug resistant epilepsy, Temporal lobe epilepsy, or cerebellar ataxia).

[015] In some variations, the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is chosen from cardiac arrhythmia, Brugada syndrome, or myocardial infarction.

[016] In some variations, the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is selected from pain and related conditions (e.g., neuropathic pain, acute/chronic pain, migraine).

[017] In some variations, the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is a muscle disorder (e.g., myotonia, neuromyotonia, cramp muscle spasms, spasticity).

[018] In some variations, the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is selected from itch and pruritis, ataxia, or cerebellar ataxias.

[019] In some variations, the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is a psychiatric disorder (e.g., major depression, anxiety, bipolar disorder, schizophrenia). [020] In other variations, the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation in a gene (e.g., KCNT1) is chosen from a learning disorder, Fragile X, neuronal plasticity, or an autism spectrum disorder.

[021] In yet other variations, the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is chosen from epileptic encephalopathy with SCN1A, SCN2A, and/or SCN8A mutations, early infantile epileptic encephalopathy, Dravet syndrome, Dravet syndrome with SCN1A mutation, generalized epilepsy with febrile seizures, intractable childhood epilepsy with generalized tonic- clonic seizures, infantile spasms, benign familial neonatal-infantile seizures, SCN2A epileptic encephalopathy, focal epilepsy with SCN3A mutation, cryptogenic pediatric partial epilepsy with SCN3A mutation, SCN8A epileptic encephalopathy, Rasmussen encephalitis, malignant migrating partial seizures of infancy, autosomal dominant nocturnal frontal lobe epilepsy, KCNQ2 epileptic encephalopathy, or KCNTl epileptic encephalopathy.

[022] Other objects and advantages will become apparent to those skilled in the art from consideration of the ensuing description.

Detailed Description of the Disclosure

[023] Provided herein, in certain aspects, are compounds and compositions useful for preventing and/or treating a disease, disorder, or condition described herein, e.g., a neurological disorder, a disorder associated with excessive neuronal excitability, or a disorder associated with a gain-of- function mutation in a gene (e.g., KCNT1). Exemplary diseases, disorders, or conditions include epilepsy and other encephalopathies (e g., MMFSI or EIMFS, ADNFLE, West syndrome, infantile spasms, epileptic encephalopathy, focal epilepsy, Ohtahara syndrome, developmental and epileptic encephalopathy, Lennox-Gastaut syndrome, seizures, leukodystrophy, leukoencephalopathy, Intellectual disability, Multifocal Epilepsy, Generalized tonic clonic seizures, Drug resistant epilepsy, Temporal lobe epilepsy, cerebellar ataxia, Asymmetric Tonic Seizures); cardiac dysfunctions (e.g., cardiac arrhythmia, Brugada syndrome, or myocardial infarction); pain and related conditions (e.g., neuropathic pain, acute/chronic pain, migraine, etc.), muscle disorders (e.g., myotonia, neuromyotonia, cramp muscle spasms, spasticity); itch and pruritis; ataxia and cerebellar ataxias; and psychiatric disorders (e.g., major depression, anxiety, bipolar disorder, schizophrenia).

I. Definitions

[024] Unless defined otherwise, all terms of art, notations and other technical and scientific terms or terminology used herein are intended to have the same meaning as is commonly understood by one of ordinary skill in the art to which the claimed subject matter pertains. In some cases, terms with commonly understood meanings are defined herein for clarity and/or for ready reference, and the inclusion of such definitions herein should not necessarily be construed to represent a substantial difference over what is generally understood in the art.

[025] Throughout this disclosure, various aspects of the claimed subject matter are presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the claimed subject matter. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range. For instance, where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit, unless the context clearly dictate otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the disclosure, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure. In some embodiments, two opposing and open-ended ranges are provided for a feature, and in such description it is envisioned that combinations of those two ranges are provided herein. For example, in some embodiments, it is described that a feature is greater than about 10 units, and it is described (such as in another sentence) that the feature is less than about 20 units, and thus, the range of about 10 units to about 20 units is described herein.

[026] The term “about” as used herein refers to the usual error range for the respective value readily known in this technical field. Reference to “about” a value or parameter herein includes (and describes) variations that are directed to that value or parameter per se. For example, description referring to “about X” includes description of “X.” [027] As used herein, including in the appended claims, the singular forms “a,” “or,” and “the” include plural referents unless the context clearly dictates otherwise. For example, “a” or “an” means “at least one” or “one or more ” It is understood that aspects and variations described herein include embodiments “consisting” and/or “consisting essentially of’ such aspects and variations.

[028] The terms “disease,” “disorder,” and “condition” are used interchangeably herein.

[029] As used herein, the term “in some embodiments,” “in other embodiments,” or the like, refers to embodiments of all aspects of the disclosure, unless the context clearly indicates otherwise.

[030] Definitions of specific functional groups and chemical terms are described in more detail below. The chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75^th Ed., inside cover, and specific functional groups are generally defined as described therein. Additionally, general principles of organic chemistry, as well as specific functional moieties and reactivity, are described, for example, in Thomas Sorrell, Organic Chemistry, University Science Books, Sausalito, 1999; Smith and March, March ’s Advanced Organic Chemistry, 5^th Edition, John Wiley & Sons, Inc., New York, 2001; Larock, Comprehensive Organic Transformations, VCH Publishers, Inc., New York, 1989; and Carruthers, Some Modern Methods of Organic Synthesis, 3^rd Edition, Cambridge University Press, Cambridge, 1987.

[031] The following terms are intended to have the meanings presented therewith below and are useful in understanding the description and intended scope of the present disclosure. When describing certain aspects of the disclosure, which may include compounds, pharmaceutical compositions containing such compounds, and methods of using such compounds and compositions, the following terms, if present, have the following meanings unless otherwise indicated. It should al so be understood that when described herein any of the moieties defined forth below may be substituted with a variety of substituents, and that the respective definitions are intended to include such substituted moieties within their scope as set out below. Unless otherwise stated, the term “substituted” is to be defined as set out below. It should be further understood that the terms “groups” and “radicals” can be considered interchangeable when used herein. The articles “a” and “an” may be used herein to refer to one or to more than one (i.e., at least one) of the grammatical objects of the article. By way of example “an analogue” means one analogue or more than one analogue. [032] When a range of values is listed, it is intended to encompass each value and sub-range within the range. For example, “CM alkyl” is intended to encompass, Ch, C2, C3, C4, C5, Ch, C1-6, Ci-

[033] “Alkyl” refers to a radical of a straight-chain or branched saturated hydrocarbon group, e.g., having 1 to 20 carbon atoms (“C1-20 alkyl”). In some embodiments, an alkyl group has 1 to 10 carbon atoms (“C1-10 alkyl”). In some embodiments, an alkyl group has 1 to. 9 carbon atoms (“C1.9 alkyl”). In some embodiments, an alkyl group has 1 to 8 carbon atoms (“Ci-s alkyl”). In some embodiments, an alkyl group has 1 to 7 carbon atoms (“C1-7 alkyl”). In some embodiments, an alkyl group has 1 to 6 carbon atoms (“C1-6 alkyl”). In some embodiments, an alkyl group has 1 to 5 carbon atoms (“C1-5 alkyl”). In some embodiments, an alkyl group has 1 to 4 carbon atoms

alkyl”). In some embodiments, an alkyl group has 1 to 3 carbon atoms (“C1-3 alkyl”). In some embodiments, an alkyl group has 1 to 2 carbon atoms (“C1-2 alkyl”). In some embodiments, an alkyl group has 1 carbon atom (“Ci alkyl”). Examples of C1-6 alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, and the like.

[034] “Alkenyl” refers to a radical of a straight-chain or branched hydrocarbon group having from 2 to 20 carbon atoms, one or more carbon-carbon double bonds (e.g., 1, 2, 3, or 4 carbon-carbon double bonds), and optionally one or more carbon-carbon triple bonds (e.g., 1, 2, 3, or 4 carboncarbon triple bonds) (“C2-20 alkenyl”). In certain embodiments, alkenyl does not contain any triple bonds. In some embodiments, an alkenyl group has 2 to 10 carbon atoms (“C2-10 alkenyl”). In some embodiments, an alkenyl group has 2 to 9 carbon atoms (“C2-9 alkenyl”). In some embodiments, an alkenyl group has 2 to 8 carbon atoms (“C2-8 alkenyl”). In some embodiments, an alkenyl group has 2 to 7 carbon atoms (“C2-7 alkenyl”). In some embodiments, an alkenyl group has 2 to 6 carbon atoms (“C2-6 alkenyl”). In some embodiments, an alkenyl group has 2 to 5 carbon atoms (“C2-5 alkenyl”). In some embodiments, an alkenyl group has 2 to 4 carbon atoms (“C2-4 alkenyl”). In some embodiments, an alkenyl group has 2 to 3 carbon atoms (“C2-3 alkenyl”). In some embodiments, an alkenyl group has 2 carbon atoms (“C2 alkenyl”). The one or more carbon-carbon double bonds can be internal (such as in 2-butenyl) or terminal (such as in 1-butenyl). Examples of C2-4 alkenyl groups include ethenyl (C2), 1-propenyl (C3), 2-propenyl (C3), 1-butenyl (C4), 2-butenyl (C4), butadienyl (C4), and the like. Examples of C2-6 alkenyl groups include the aforementioned C2-4 alkenyl groups as well as pentenyl (Ci), pentadienyl (C5), hexenyl (Ce), and the like. Additional examples of alkenyl include heptenyl (C7), octenyl (Cs), octatrienyl (Cs), and the like.

[035] “Alkoxy” refers to a radical of a straight-chain or branched hydrocarbon group, e.g., having 1 to 20 carbon atoms, having a single bond to oxygen. In some embodiments, an alkoxy has 1-2 carbon atoms, such as -OCH3 or -OCH2CH3.

[036] “Alkynyl” refers to a radical of a straight-chain or branched hydrocarbon group having from 2 to 20 carbon atoms, one or more carbon-carbon triple bonds (e.g., 1, 2, 3, or 4 carbon-carbon triple bonds), and optionally one or more carbon-carbon double bonds (e.g., 1, 2, 3, or 4 carboncarbon double bonds) (“C2-20 alkynyl”). In certain embodiments, alkynyl does not contain any double bonds. In some embodiments, an alkynyl group has 2 to 10 carbon atoms (“C2-10 alkynyl”). In some embodiments, an alkynyl group has 2 to 9 carbon atoms (“C2-9 alkynyl”). In some embodiments, an alkynyl group has 2 to 8 carbon atoms (“C2-8 alkynyl”). In some embodiments, an alkynyl group has 2 to 7 carbon atoms (“C2-7 alkynyl”). In some embodiments, an alkynyl group has 2 to 6 carbon atoms (“C2-6 alkynyl”). In some embodiments, an alkynyl group has 2 to 5 carbon atoms (“C2-5 alkynyl”). In some embodiments, an alkynyl group has 2 to 4 carbon atoms (“C2-4 alkynyl”). In some embodiments, an alkynyl group has 2 to 3 carbon atoms (“C2-3 alkynyl”). In some embodiments, an alkynyl group has 2 carbon atoms (“C2 alkynyl”). The one or more carbon-carbon triple bonds can be internal (such as in 2-butynyl) or terminal (such as in 1-butynyl). Examples of C2-4 alkynyl groups include, without limitation, ethynyl (C2), 1-propynyl (C3), 2-propynyl (C3), 1-butynyl (C4), 2-butynyl (C4), and the like. Examples of C2-6 alkenyl groups include the aforementioned C2-4 alkynyl groups as well as pentynyl (C5), hexynyl (Ce), and the like. Additional examples of alkynyl include heptynyl (C7), octynyl (Cs), and the like.

[037] “Aryl” refers to a radical of a monocyclic or polycyclic (e.g., bicyclic or tricyclic) 4n+2 aromatic ring system (e.g., having 6, 10, or 1471 electrons shared in a cyclic array) having 6-14 ring carbon atoms and zero heteroatoms provided in the aromatic ring system (“Ce-14 aryl”). In some embodiments, an aryl group has six ring carbon atoms (“Ce aryl”; e.g., phenyl). In some embodiments, an aryl group has ten ring carbon atoms (“C10 aryl”; e.g., naphthyl such as 1-naphthyl and 2-naphthyl). In some embodiments, an aryl group has fourteen ring carbon atoms (“C14 aryl”; e.g., anthracyl). “Aryl” also includes ring systems wherein the aryl ring, as defined above, is fused with one or more carbocyclyl or heterocyclyl groups wherein the radical or point of attachment is on the aryl ring, and in such instances, the number of carbon atoms continue to designate the number of carbon atoms in the aryl ring system. Typical aryl groups include, but are not limited to, groups derived from aceanthrylene, acenaphthylene, acephenanthrylene, anthracene, azulene, benzene, chrysene, coronene, fluoranthene, fluorene, hexacene, hexaphene, hexalene, as-indacene, s-indacene, indane, indene, naphthalene, octacene, octaphene, octalene, ovalene, penta-2,4-diene, pentacene, pentalene, pentaphene, perylene, phenalene, phenanthrene, picene, pleiadene, pyrene, pyranthrene, rubicene, triphenylene, and trinaphthalene. Particularly aryl groups include phenyl, naphthyl, indenyl, and tetrahydronaphthyl .

[038] “Hetero” when used to describe a compound or a group present on a compound means that one or more carbon atoms in the compound or group have been replaced by a nitrogen, oxygen, or sulfur heteroatom. Hetero may be applied to any of the alkyl groups described above such as alkyl, e.g., heteroalkyl; alkenyl, e.g., heteroalkenyl; alkynyl, e.g., heteroal kynyl; carbocyclyl, e.g., heterocyclyl; aryl, e.g., heteroaryl, and the like having from 1 to 5, and particularly from 1 to 3 heteroatoms.

[039] “Heteroaryl” refers to a radical of a 5-10 membered monocyclic or bicyclic 4n+2 aromatic ring system (e.g., having 6 or 10 7i electrons shared in a cyclic array) having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen and sulfur (“5-10 membered heteroaryl”). In heteroaryl groups that contain one or more nitrogen atoms, the point of attachment can be a carbon or nitrogen atom, as valency permits. Heteroaryl bicyclic ring systems can include one or more heteroatoms in one or both rings. “Heteroaryl” includes ring systems wherein the heteroaryl ring, as defined above, is fused with one or more carbocyclyl or heterocyclyl groups wherein the point of attachment is on the heteroaryl ring, and in such instances, the number of ring members continue to designate the number of ring members in the heteroaryl ring system. “Heteroaryl” also includes ring systems wherein the heteroaryl ring, as defined above, is fused with one or more aryl groups wherein the point of attachment is either on the aryl or heteroaryl ring, and in such instances, the number of ring members designates the number of ring members in the fused (aryl/heteroaryl) ring system. Bicyclic heteroaryl groups wherein one ring does not contain a heteroatom (e.g., indolyl, quinolinyl, carbazolyl, and the like) the point of attachment can be on either ring, i.e., either the ring bearing a heteroatom (e g., 2-indolyl) or the ring that does not contain a heteroatom (e.g., 5-indolyl).

[040] In some embodiments, a heteroaryl group is a 5-10 membered aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur (“5-10 membered heteroaryl”). In some embodiments, a heteroaryl group is a 5-8 membered aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur (“5-8 membered heteroaryl”). In some embodiments, a heteroaryl group is a 5-6 membered aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms provided in the aromatic ring system, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur (“5-6 membered heteroaryl”). In some embodiments, the 5-6 membered heteroaryl has 1-3 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6 membered heteroaryl has 1-2 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6 membered heteroaryl has 1 ring heteroatom selected from nitrogen, oxygen, and sulfur.

[041] “Carbocyclyl” or “carbocyclic” refers to a radical of a non-aromatic cyclic hydrocarbon group having from 3 to 10 ring carbon atoms (“C3-10 carbocyclyl”) and zero heteroatoms in the non-aromatic ring system. In some embodiments, a carbocyclyl group has 3 to 8 ring carbon atoms (“C3-8 carbocyclyl”). In some embodiments, a carbocyclyl group has 3 to 6 ring carbon atoms (“C3-6 carbocyclyl”). In some embodiments, a carbocyclyl group has 3 to 6 ring carbon atoms (“C3-6 carbocyclyl”). In some embodiments, a carbocyclyl group has 5 to 10 ring carbon atoms (“C5-10 carbocyclyl”). Exemplary C3-6 carbocyclyl groups include, without limitation, cyclopropyl (C3), cyclopropenyl (C3), cyclobutyl (C4), cyclobutenyl (C4), cyclopentyl (C5), cyclopentenyl (C5), cyclohexyl (Ce), cyclohexenyl (Ce), cyclohexadienyl (Ce), and the like. Exemplary C3-5 carbocyclyl groups include, without limitation, the aforementioned C3-6 carbocyclyl groups as well as cycloheptyl (C7), cycloheptenyl (C7), cycloheptadienyl (C7), cycloheptatrienyl (C7), cyclooctyl (Cs), cyclooctenyl (Cs), bicyclo[2.2.1]heptanyl (C7), bicyclo[2.2.2]octanyl (Cs), and the like. Exemplary C3-10 carbocyclyl groups include, without limitation, the aforementioned C3-8 carbocyclyl groups as well as cyclononyl (C9), cyclononenyl (C9), cyclodecyl (C10), cyclodecenyl (C10), octahydro-lH-indenyl (C9), decahydronaphthalenyl (Cio), spiro[4.5]decanyl (Cio), and the like. As the foregoing examples illustrate, in certain embodiments, the carbocyclyl group is either monocyclic (“monocyclic carbocyclyl”) or contain a fused, bridged or spiro ring system such as a bicyclic system (“bicyclic carbocyclyl”) and can be saturated or can be partially unsaturated. “Carbocyclyl” also includes ring systems wherein the carbocyclyl ring, as defined above, is fused with one or more aryl or heteroaryl groups wherein the point of attachment is on the carbocyclyl ring, and in such instances, the number of carbons continue to designate the number of carbons in the carbocyclic ring system.

[042] “Heterocyclyl” or “heterocyclic” refers to a radical of a 3- to 10-membered non-aromatic ring system having ring carbon atoms and 1 to 4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, sulfur, boron, phosphorus, and silicon (“3-10 membered heterocyclyl”). In heterocyclyl groups that contain one or more nitrogen atoms, the point of attachment can be a carbon or nitrogen atom, as valency permits. A heterocyclyl group can either be monocyclic (“monocyclic heterocyclyl”) or a fused, bridged or spire ring system such as a bicyclic system (“bicyclic heterocyclyl”), and can be saturated or can be partially unsaturated. Heterocyclyl bicyclic ring systems can include one or more heteroatoms in one or both rings. “Heterocyclyl” also includes ring systems wherein the heterocyclyl ring, as defined above, is fused with one or more carbocyclyl groups wherein the point of attachment is either on the carbocyclyl or heterocyclyl ring, or ring systems wherein the heterocyclyl ring, as defined above, is fused with one or more aryl or heteroaryl groups, wherein the point of attachment is on the heterocyclyl ring, and in such instances, the number of ring members continue to designate the number of ring members in the heterocyclyl ring system.

[043] In some embodiments, a heterocyclyl group is a 5-10 membered non-aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, sulfur, boron, phosphorus, and silicon (“5-10 membered heterocyclyl”). In some embodiments, a heterocyclyl group is a 5-8 membered non-aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur (“5-8 membered heterocyclyl”). In some embodiments, a heterocyclyl group is a 5-6 membered non-aromatic ring system having ring carbon atoms and 1-4 ring heteroatoms, wherein each heteroatom is independently selected from nitrogen, oxygen, and sulfur (“5-6 membered heterocyclyl”). In some embodiments, the 5-6 membered heterocyclyl has 1- 3 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6 membered heterocyclyl has 1-2 ring heteroatoms selected from nitrogen, oxygen, and sulfur. In some embodiments, the 5-6 membered heterocyclyl has one ring heteroatom selected from nitrogen, oxygen, and sulfur.

[044] Exemplary 3-membered heterocyclyl groups containing one heteroatom include, without limitation, azirdinyl, oxiranyl, thiorenyl. Exemplary 4-membered heterocyclyl groups containing one heteroatom include, without limitation, azetidinyl, oxetanyl and thietanyl. Exemplary 5-membered heterocyclyl groups containing one heteroatom include, without limitation, tetrahydrofuranyl, dihydrofuranyl, tetrahydrothiophenyl, dihydrothiophenyl, pyrrolidinyl, dihydropyrrolyl and pyrrolyl-2, 5-dione. Exemplary 5-membered heterocyclyl groups containing two heteroatoms include, without limitation, dioxolanyl, oxasulfuranyl, disulfuranyl, and oxazolidin-2- one. Exemplary 5-membered heterocyclyl groups containing three heteroatoms include, without limitation, triazolinyl, oxadiazolinyl, and thiadiazolinyl. Exemplary 6-membered heterocyclyl groups containing one heteroatom include, without limitation, piperidinyl, tetrahydropyranyl, dihydropyridinyl, and thianyl. Exemplary 6-membered heterocyclyl groups containing two heteroatoms include, without limitation, piperazinyl, morpholinyl, dithianyl, dioxanyl. Exemplary 6- membered heterocyclyl groups containing three heteroatoms include, without limitation, triazinanyl. Exemplary 7-membered heterocyclyl groups containing one heteroatom include, without limitation, azepanyl, oxepanyl and thiepanyl. Exemplary 8-membered heterocyclyl groups containing one heteroatom include, without limitation, azocanyl, oxecanyl and thiocanyl. Exemplary 5-membered heterocyclyl groups fused to a C>, aryl ring (also referred to herein as a 5,6-bicyclic heterocyclic ring) include, without limitation, indolinyl, isoindolinyl, dihydrobenzofuranyl, dihydrobenzothienyl, benzoxazolinonyl, and the like. Exemplary 6-membered heterocyclyl groups fused to an aryl ring (also referred to herein as a 6,6-bicyclic heterocyclic ring) include, without limitation, tetrahydroquinolinyl, tetrahydroisoquinolinyl, and the like.

[045] “Halo” or “halogen” refers to a fluorine atom (i.e., fluoro or -F), a chlorine atom (i.e., chloro or -Cl), a bromine atom (i.e., bromo or -Br), and an iodine atom (i.e., iodo or -I). In certain embodiments, the halo group is fluoro or chloro. [046] “Haloalkyl” refers to an alkyl group substituted with one or more halogen atoms.

[047] In general, the term “substituted,” whether preceded by the term “optionally” or not, means that at least one hydrogen present on a group (e.g., a carbon or nitrogen atom) is replaced with a permissible substituent, e.g., a substituent which upon substitution results in a stable compound, e.g , a compound which does not spontaneously undergo transformation such as by rearrangement, cyclization, elimination, or other reaction. Unless otherwise indicated, a “substituted” group has a substituent at one or more substitutable positions of the group, and when more than one position in any given structure is substituted, the substituent is either the same or different at each position.

[048] The term “pharmaceutically acceptable salt” refers to those salts which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of humans and lower animals without undue toxicity, irritation, allergic response and the like, and are commensurate with a reasonable benefit/risk ratio. The general concept of pharmaceutically acceptable salts has been discussed in the art, including, for example, Berge et al., which describes pharmaceutically acceptable salts in detail in J Pharmaceutical Sciences (1977) 66: 1-19. Pharmaceutically acceptable salts of the compounds described herein include those derived from suitable inorganic and organic acids and bases. Examples of pharmaceutically acceptable, nontoxic acid addition salts are salts of an amino group formed with inorganic acids such as hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid and perchloric acid or with organic acids such as acetic acid, oxalic acid, maleic acid, tartaric acid, citric acid, succinic acid or malonic acid or by using other methods used in the art such as ion exchange. Other pharmaceutically acceptable salts include adipate, alginate, ascorbate, aspartate, benzenesulfonate, benzoate, bisulfate, borate, butyrate, camphorate, camphorsulfonate, citrate, cyclopentanepropionate, digluconate, dodecyl sulfate, ethanesulfonate, formate, fumarate, glucoheptonate, glycerophosphate, gluconate, hemisulfate, heptanoate, hexanoate, hydroiodide, 2- hydroxy-ethanesulfonate, lactobionate, lactate, laurate, lauryl sulfate, malate, maleate, malonate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, nitrate, oleate, oxalate, palmitate, pamoate, pectinate, persulfate, 3 -phenylpropionate, phosphate, picrate, pivalate, propionate, stearate, succinate, sulfate, tartrate, thiocyanate, p-toluenesulfonate, undecanoate, valerate salts, and the like. Pharmaceutically acceptable salts derived from appropriate bases include alkali metal, alkaline earth metal, ammonium and N⁺(Ci-4alkyl)4 salts. Representative alkali or alkaline earth metal salts include sodium, lithium, potassium, calcium, magnesium, and the like. Further pharmaceutically acceptable salts include, when appropriate, nontoxic ammonium, quaternary ammonium, and amine cations formed using counterions such as halide, hydroxide, carboxylate, sulfate, phosphate, nitrate, lower alkyl sulfonate, and aryl sulfonate.

[049] The term “modified-release polymer” refers to a polymer that is used in a formulation (e.g., tablets and capsules) to modify the release rate of the drug upon administration to a subject. For example, a modified-release polymer is used to dissolve a drug over time in order to be released slower and steadier into the bloodstream. For example, a modified-release polymer is a controlled- release polymer. For example, a modified-release polymer or a controlled-release polymer is an HPMC polymer. In some embodiments, a modified-release polymer may include hydrophilic matrix polymers (e.g., hypromellose, hydroxyl -propyl methylcellulose (HPMC)), hydrophobic matrix polymers (e.g., ethyl cellulose, ethocel), or polyacrylate polymers (e.g., Eudragit® RL100, Eudragit® RS100).

[050] The term “diluent” as used herein refers to an excipient used to increase weight and improve content uniformity. For example, diluents include cellulose derivatives (e.g., microcrystalline cellulose), starches (e.g., hydrolyzed starches, and partially pregelatinized starches), anhydrous lactose, lactose monohydrate, di-calcium phosphate (DCP), sugar alcohols (e.g., sorbitol, xylitol and mannitol)).

[051] The term “glidant” as used herein refers to an excipient used to promote powder flow by reducing interparticle friction and cohesion. For example, glidants include fumed silica (e.g., colloidal silicon dioxide), talc, and magnesium carbonate.

[052] The term “lubricant” as used herein refers to an excipient used to prevent ingredients from clumping together and from sticking to the tablet punches or capsule filling machine. Lubricants are also used to ensure that tablet formation and ejection can occur with low friction between the solid and die wall. For example, lubricants include magnesium stearate, calcium stearate, stearic acid, talc, silica, and fats (e.g., vegetable stearin).

[053] The term “coating” as used herein refers to an excipient to protect tablet ingredients from deterioration by moisture in the air and make large or unpleasant-tasting tablets easier to swallow. [054] The embodiments disclosed herein are not intended to be limited in any manner by the above exemplary listing of chemical groups and substituents. Those skilled in the art will recognize that several embodiments are possible within the scope and spirit of the present disclosure. The following description illustrates the disclosure and, of course, should not be construed in any way as limiting the scope of the inventions described herein.

IL Compounds and Compositions

[055] In one aspect, provided is a compound of Formula (III) having a sulfonamide core:

or a pharmaceutically acceptable salt thereof, wherein:

X is chosen from -C- or -N-;

Ri is chosen from -H or an alkyl;

R2 is chosen from -H, an alkyl, an alkoxy, or a halogen;

R3 is chosen from -H, an alkyl, or a halogen; and n is 1 or 2.

[056] In some embodiments of Formula (III), X is -C-, and in some embodiments, X is -N-. In certain embodiments of Formula (III), Ri is -H, and in certain embodiments, Ri is -CH3. In certain embodiments of Formula (III), X is -C-, n is 2 and Ri is -H, such that Formula (III) forms a benzothiazine dioxide. In certain embodiments, R2 is chosen from -H, -OCH3, or -F. In certain embodiments of Formula (III), R3 is -Cl. In embodiments disclosed herein of Formula (III), n is 1 or 2, such that Formula (III) contains a 5- or 6-membered heteroaryl, respectively. In certain embodiments, X is chosen from -C- or -N-; Ri is chosen from -H or an alkyl; R2 is chosen from -H, an alkoxy, or a halogen; R3 is a halogen; and n is 1 or 2.

[057] In one aspect, provided is a compound of Formula (III) having a sulfonamide core, or a pharmaceutically acceptable salt thereof, selected from the compounds:

[058] In some variations of the foregoing, the compound is an optically active compound. In some variations, the compound is a single enantiomer. In certain variations, the compound is the (R)- enantiomer. In other variations, the compound is the (S)-enantiomer.

[059] Compounds described herein can comprise one or more asymmetric centers, and thus can exist in various isomeric forms, e.g., enantiomers and/or diastereomers. For example, the compounds described herein can be in the form of an individual enantiomer, diastereomer or geometric isomer, or can be in the form of a mixture of stereoisomers, including racemic mixtures and mixtures enriched in one or more stereoisomer. Isomers can be isolated from mixtures by methods known to those skilled in the art, including chiral high pressure liquid chromatography (HPLC) and the formation and crystallization of chiral salts; preferred isomers can be prepared by asymmetric syntheses. See, for example, Jacques et al., Enantiomers, Racemates and Resolutions (Wiley Interscience, New York, 1981); Wilen et al, Tetrahedron 33:2725 (1977); Eliel, Stereochemistry of Carbon Compounds (McGraw-Hill, NY, 1962); and Wilen, Tables of Resolving Agents and Optical Resolutions p. 268 (E.L. Eliel, Ed., Univ, of Notre Dame Press, Notre Dame, IN 1972). Embodiments disclosed herein additionally encompass compounds described herein as individual isomers substantially free of other isomers, and alternatively, as mixtures of various isomers.

[060] As used herein a pure enantiomeric compound is substantially free from other enantiomers or stereoisomers of the compound i.e., in enantiomeric excess). In other words, an “S” form of the compound is substantially free from the “R” form of the compound and is, thus, in enantiomeric excess of the “R” form. The term “enantiomerically pure” or “pure enantiomer” denotes that the compound comprises more than 75% by weight, such as more than 80% by weight, more than 85% by weight, more than 90% by weight, more than 91% by weight, more than 92% by weight, more than 93% by weight, more than 94% by weight, more than 95% by weight, more than 96% by weight, more than 97% by weight, more than 98% by weight, more than 98.5% by weight, more than 99% by weight, more than 99.2% by weight, more than 99.5% by weight, more than 99.6% by weight, more than 99.7% by weight, more than 99.8% by weight, or more than 99.9% by weight, of the enantiomer. In certain embodiments, the weights are based upon total weight of all enantiomers or stereoisomers of the compound.

[061] In certain aspects, provided are compositions comprising the compounds described herein. In some embodiments, an enantiomerically pure compound can be present in the compositions with other active or inactive ingredients. For example, a pharmaceutical composition comprising enantiomerically pure R-compound can comprise, for example, about 90% excipient and about 10% enantiomerically pure R-compound. In certain embodiments, the enantiomerically pure R-compound in such compositions can, for example, comprise at least about 95% by weight R-compound and at most about 5% by weight S-compound, by total weight of the compound. For example, a pharmaceutical composition comprising enantiomerically pure S-compound can comprise, for example, about 90% excipient and about 10% enantiomerically pure S-compound. In certain embodiments, the enantiomerically pure S-compound in such compositions can, for example, comprise at least about 95% by weight S-compound and at most about 5% by weight R-compound, by total weight of the compound. In certain embodiments, the active ingredient can be formulated with little or no excipient or carrier.

[062] Compounds described herein may also comprise one or more isotopic substitutions. For example, H may be in any isotopic form, including ¹H, ²H (D or deuterium), and ³H (T or tritium); C may be in any isotopic form, including ¹²C, ¹³C, and ¹⁴C. 0 may be in any isotopic form, including ¹⁶O and ¹⁸O, and F may be in any isotopic form, including ¹⁸F and ¹⁹F.

III. Methods of Treatment

[063] The compounds and compositions described above and herein can be used to treat a neurological disorder, a disorder associated with excessive neuronal excitability, or a disorder associated with a gain-of-function mutation in a gene (e.g., KCNT1).

[064] In some aspects, provided are methods of treating a neurological disorder, a disorder associated with excessive neuronal excitability, or a disorder associated with a gain-of-function mutation of a gene, comprising administering to a subject in need thereof an effective amount of any of the compounds described herein or a pharmaceutically acceptable salt thereof, or pharmaceutical compositions comprising such compounds or a pharmaceutically acceptable salt thereof.

[065] Exemplary diseases, disorders, or conditions include epilepsy and other encephalopathies (e.g., MMFSI or EIMFS, ADNFLE, West syndrome, infantile spasms, epileptic encephalopathy, developmental and epileptic encephalopathy (DEE), early infantile epileptic encephalopathy (EIEE), generalized epilepsy, focal epilepsy, multifocal epilepsy, temporal lobe epilepsy, Ohtahara syndrome, early myoclonic encephalopathy, Lennox-Gastaut syndrome, drug resistant epilepsy, seizures (e.g., frontal lobe seizures, generalized tonic clonic seizures, asymmetric tonic seizures, focal seizures), leukodystrophy, hypomyelinating leukodystrophy, and leukoencephalopathy), cardiac dysfunctions (e.g., cardiac arrhythmia, Brugada syndrome, myocardial infarction), pulmonary vasculopathy/hemorrhage, pain and related conditions (e.g., neuropathic pain, acute/chronic pain, migraine, etc.), muscle disorders (e.g., myotonia, neuromyotonia, cramp muscle spasms, spasticity), itch and pruritis, movement disorders (e.g., ataxia and cerebellar ataxias), psychiatric disorders (e.g., major depression, anxiety, bipolar disorder, schizophrenia, attention-deficit hyperactivity disorder), neurodevelopmental disorder, learning disorders, intellectual disability, Fragile X, neuronal plasticity, and autism spectrum disorders.

[066] In some embodiments, the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation in a gene (e.g., KCNT1) is selected from EIMFS, ADNFLE, or West syndrome. In some embodiments, the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation in a gene (e.g., KCNT1) is selected from infantile spasms, epileptic encephalopathy, focal epilepsy, Ohtahara syndrome, developmental and epileptic encephalopathy, or Lennox-Gastaut syndrome. In some embodiments, the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of- function mutation in a gene (e.g., KCNT1) is seizure. In some embodiments, the neurological disorder, the disorder associated with excessive neuronal excitability, and/or the disorder associated with a gain-of-function mutation in a gene (e.g., KCNT1) is selected from cardiac arrhythmia, Brugada syndrome, or myocardial infarction.

[067] In some embodiments, the neurological disorder, the disorder associated with excessive neuronal excitability, and/or the disorder associated with a gain-of-function mutation in a gene (e.g., KCNT1) is selected from a learning disorder, Fragile X, intellectual function, neuronal plasticity, a psychiatric disorder, or an autism spectrum disorder.

[068] Accordingly, the compounds, pharmaceutically acceptable salts thereof, and compositions disclosed herein can be administered to a subject with a neurological disorder, a disorder associated with excessive neuronal excitability, or a disorder associated with a gain-of-function mutation in a gene such as KCNT1 (e.g., EIMFS, ADNFLE, West syndrome, infantile spasms, epileptic encephalopathy, focal epilepsy, Ohtahara syndrome, developmental and epileptic encephalopathy, Lennox-Gastaut syndrome, seizures, cardiac arrhythmia, Brugada syndrome, and myocardial infarction). [069] EIMFS is a rare and debilitating genetic condition characterized by an early onset (before 6 months of age) of almost continuous heterogeneous focal seizures, where seizures appear to migrate from one brain region and hemisphere to another. Patients with EIMFS are generally intellectually impaired, non-verbal, and non-ambulatory. While several genes have been implicated to date, the gene that is most commonly associated with EIMFS is KCNT1. Several de novo mutations in KCNT1 have been identified in patients with EIMFS, including V271F, G288S, R428Q, R474Q, R474H, R474C, I760M, A934T, P924L, G243S, H257D, A259D, R262Q, Q270E, L274I, F346L, C377S, R398Q, P409S, A477T, F502V, M516V, Q550del, K629E, K629N, I760F, E893K, M896K, R933G, R950Q, and KI 154Q. Barcia et al. (2012) Nat Genet. 44: 1255-1260; Ishii et al. (2013) Gene 531:467- 471; McTague et al. (2013) Brain. 136: 1578-1591; Epi4K Consortium & Epilepsy Phenome/Genome Project. (2013) Nature 501 :217-221; Lim et al. (2016) Neurogenetics; Ohba et al. (2015) Epilepsia 56:el21-el28; Zhou et al. (2018) Genes Brain Behav. el2456; Moller et al. (2015) Epilepsia, el 14-20; Numis et al. (2018) Epilepsia. 1889-1898; Madaan et al. Brain Dev. 40(3):229-232; McTague et al. (2018) Neurology. 90(l):e55-e66; Kawasaki et al. (2017) J Pediatr. 191:270-274; Kim et al. (2014) Cell Rep. 9(5): 1661-1672; Ohba et al. (2015) Epilepsia. 56(9):el21-8; Rizzo et al. (2016) Mol Cell Neurosci. 72:54-63; Zhang et al. (2017) Clin Genet. 91(5):717-724; Mikati et al. (2015) Ann Neurol. 78(6):995-9; Baumer et al. (2017) Neurology. 89(21):2212; Dilena et al. (2018) Neurotherapeutics. 15(4): 1112-1126. These mutations may be gain-of-function, missense mutations that are dominant (i.e., present on only one allele) and result in change-in-function of the encoded potassium channel that causes a marked increase in whole cell current when tested in Xenopus oocyte or mammalian expression systems (see e.g. Milligan et al. (2015) Ann Neurol. 75(4): 581-590; Barcia et al. (2012) Nat Genet. 44(11): 1255-1259; and Mikati et al. (2015) Ann Neurol. 78(6): 995-999),

[070] ADNFLE has a later onset than EIMFS, generally in mid-childhood, and is generally a less severe condition. It is characterized by nocturnal frontal lobe seizures and can result in psychiatric, behavioral, and cognitive disabilities in patients with the condition. While ADNFLE is associated with genes encoding several neuronal nicotinic acetylcholine receptor subunits, mutations in the KCNT1 gene have been implicated in more severe cases of the disease (Heron et al. (2012) Nat Genet. 44: 1188-1190). Functional studies of the mutated KCNT1 genes associated with ADNFLE indicated that the underlying mutations (M896I, R398Q, Y796H, and R928C) were dominant, gain- of-function mutations (Milligan et al. (2015) Ann Neurol. 75(4): 581-590; Mikati et al. (2015) Ann Neurol. 78(6): 995-999).

[071] West syndrome is a severe form of epilepsy composed of a triad of infantile spasms, an interictal electroencephalogram (EEG) pattern termed hypsarrhythmia, and mental retardation, although a diagnosis can be made when one of these elements is missing. Mutations in KCNT1, including G652V and R474H, have been associated with West syndrome (Fukuoka et al. (2017) Brain Dev 39:80-83 and Ohba et al. (2015) Epilepsia 56:el21-el28). Treatment targeting the KCNT1 channel suggests that these mutations are gain-of-function mutations (Fukuoka et al. (2017) Brain Dev 39: SO- 83).

[072] In one aspect, disclosed herein is a method of treating treat a disorder associated with excessive neuronal excitability or a disorder associated with a gain-of-function mutation in a gene such as KCNT1 (for example, epilepsy and other encephalopathies (e.g., MMFSI or EIMFS, ADNFLE, West syndrome, infantile spasms, epileptic encephalopathy, focal epilepsy, Ohtahara syndrome, DEE, Lennox-Gastaut syndrome, seizures, leukodystrophy, leukoencephalopathy, intellectual disability, Multifocal Epilepsy, Generalized tonic clonic seizures, Drug resistant epilepsy, Temporal lobe epilepsy, cerebellar ataxia, Asymmetric Tonic Seizures), cardiac dysfunctions (e.g., cardiac arrhythmia, Brugada syndrome, myocardial infarction), pain and related conditions (e.g., neuropathic pain, acute/chronic pain, migraine, etc.), muscle disorders (e.g. myotonia, neuromyotonia, cramp muscle spasms, spasticity), itch and pruritis, ataxia and cerebellar ataxias, psychiatric disorders (e.g., major depression, anxiety, bipolar disorder, schizophrenia), learning disorders, Fragile X, neuronal plasticity, and autism spectrum disorders), comprising administering to a subject in need thereof a compound disclosed herein or a pharmaceutically acceptable salt thereof or a pharmaceutical composition disclosed herein.

[073] In some examples, the subject presenting with a disorder that may be associated with a gain-of-function mutation in KCNT1 is genotyped to confirm the presence of a known gain-of- function mutation in KCNT1 prior to administration of the compounds or a pharmaceutically acceptable salt thereof or compositions disclosed herein. For example, whole exome sequencing can be performed on the subject. Gain-of-function mutations associated with EIMFS may include, but are not limited to, V271F, G288S, R428Q, R474Q, R474H, R474C, I760M, A934T, P924L, G243S, H257D, A259D, R262Q, Q270E, L274I, F346L, C377S, R398Q, P409S, A477T, F502V, M516V, Q550del, K629E, K629N, I760F, E893K, M896K, R933G, R950Q, and K1154Q. Gain-of-function mutations associated with ADNFLE may include, but are not limited to, M896I, R398Q, Y796H, R928C, and G288S. Gain-of-function mutations associated with West syndrome may include, but are not limited to, G652V and R474H. Gain-of-function mutations associated with temporal lobe epilepsy may include, but are not limited to, R133H and R565H. Gain-of-function mutations associated with Lennox-Gastaut may include, but are not limited to, R209C. Gain-of-function mutations associated with seizures may include, but are not limited to, A259D, G288S, R474C, and R474H. Gain-of- function mutations associated with leukodystrophy may include, but are not limited to, G288S and Q906H. Gain-of-function mutations associated with Multifocal Epilepsy may include, but are not limited to, V340M. Gain-of-function mutations associated with early-onset epilepsy (EOE) may include, but are not limited to, F346L and A934T. Gain-of-function mutations associated with Early- onset epileptic encephalopathies (EOEE) may include, but are not limited to, R428Q. Gain-of- function mutations associated with developmental and epileptic encephalopathies may include, but are not limited to, F346L, R474H, and A934T. Gain-of-function mutations associated with epileptic encephalopathies may include, but are not limited to, L437F, Y796H, P924L, and R961H. Gain-of- function mutations associated with Early Infantile Epileptic Encephalopathy (EIEE) may include, but are not limited to, M896K. Gain-of-function mutations associated with drug-resistant epilepsy and generalized tonic-clonic seizure may include, but are not limited to, F346L. Gain-of-function mutations associated with migrating partial seizures of infancy may include, but are not limited to, R428Q. Gain-of-function mutations associated with Leukoencephalopathy may include, but are not limited to, F932I. Gain-of-function mutations associated with NFLE may include, but are not limited to, A934T and R950Q. Gain-of-function mutations associated with Ohtahara syndrome may include, but are not limited to, A966T. Gain-of-function mutations associated with infantile spasms may include, but are not limited to, P924L. Gain-of-function mutations associated with Brugada Syndrome may include, but are not limited to, R1106Q. Gain-of-function mutations associated with Brugada Syndrome may include, but are not limited to, R474H.

[074] In other examples, the subject is first genotyped to identify the presence of a mutation in KCNT1, and this mutation is then confirmed to be a gain-of-function mutation using standard in vitro assays, such as those described in Milligan et al. (2015) Ann Neurol. 75(4): 581-590. Typically, the presence of a gain-of-function mutation is confirmed when the expression of the mutated KCNT1 allele results in an increase in whole cell current compared to the whole cell current resulting from expression of wild-type KCNT1, as may be assessed using whole-cell electrophysiology (such as described in Milligan et al. (2015) Ann Neurol. 75(4): 581-590; Barcia et al. (2012) Nat Genet. 44(11): 1255-1259; Mikati etal. (2015) Ann Neurol. 78(6): 995-999; or Rizzo et al. Mol Cell Neurosci. (2016) 72:54-63). This increase of whole cell current can be, for example, an increase of at least or about 50%, 100%, 150%, 200%, 250%, 300%, 350%, 400%, or more. The subject can then be confirmed to have a disease or condition associated with a gain-of-function mutation in KCNT1.

[075] In particular examples, the subject is confirmed as having a KCNT1 allele containing a gain-of-function mutation (e.g., V271F, G288S, R398Q, R428Q, R474Q, R474H, R474C, G652V, I760M, Y796H, M896I, P924L, R928C, or A934T).

[076] The compounds or pharmaceutically acceptable salts thereof disclosed herein or the pharmaceutical composition disclosed herein (e.g., a pharmaceutical composition comprising a compound or pharmaceutically acceptable salt thereof disclosed herein, and a pharmaceutically acceptable excipient) can also be used therapeutically for conditions associated with excessive neuronal excitability where the excessive neuronal excitability is not necessarily the result of a gain- of-function mutation in KCNT1. Even in instances where the disease is not the result of increased KCNT1 expression and/or activity, inhibition of KCNT1 expression and/or activity can nonetheless result in a reduction in neuronal excitability, thereby providing a therapeutic effect. Thus, the compounds or pharmaceutically acceptable salts thereof disclosed herein or the pharmaceutical compositions disclosed herein can be used to treat a subject with conditions associated with excessive neuronal excitability, for example, epilepsy and other encephalopathies (e.g., EIMFS, ADNFLE, West syndrome, infantile spasms, epileptic encephalopathy, focal epilepsy, Ohtahara syndrome, developmental and epileptic encephalopathy, and Lennox-Gastaut syndrome, seizures) or cardiac dysfunctions (e.g., cardiac arrhythmia, Brugada syndrome, myocardial infarction), regardless of whether or not the disorder is associated with a gain-of-function mutation in KCNT1.

[077] In some variations of the foregoing, a “subject” to which administration is contemplated includes, but is not limited to, humans (i.e., a male or female of any age group, e.g., a pediatric subject (e.g., an infant, child, adolescent) or an adult subject (e.g., a young adult, middle-aged adult, or senior adult)) and/or a non-human animal, e.g., a mammal such as primates (e g., cynomolgus monkeys, rhesus monkeys), cattle, pigs, horses, sheep, goats, rodents, cats, and/or dogs. In certain embodiments, the subject is a human. In certain embodiments, the subject is a non-human animal.

[078] Some variations of the foregoing, “treating” or “treatment”, as used herein, contemplate an action that occurs while a subject is suffering from the specified disease, disorder or condition, which reduces the severity of the disease, disorder or condition, or retards or slows the progression of the disease, disorder or condition (also “therapeutic treatment”). In some variations, “treating” or “treatment” refers to a method or procedure for obtaining beneficial or desired results — for example, clinical results. Beneficial or desired results may include: (1) alleviating one or more symptoms caused by or associated with a disease, disorder, or condition; (2) reducing the extent of the disease, disorder, or condition; (3) slowing or stopping the development or progression of one or more symptoms caused by or associated with the disease, disorder, or condition (for example, stabilizing the disease, disorder, or condition); and (4) relieving the disease, for example, by causing the regression of one or more clinical symptoms (e.g., ameliorating the disease state, enhancing the effect of another medication, delaying or stopping the progression of the disease, increasing the quality of life, and/or prolonging survival rates).

[079] In some variations of the foregoing, an “effective amount” of a compound or pharmaceutically acceptable salt thereof refers to an amount sufficient to elicit the desired biological response. As will be appreciated by those of ordinary skill in this art, the effective amount of a compound or pharmaceutically acceptable salt thereof may vary depending on such factors as the desired biological endpoint, the pharmacokinetics of the compound or pharmaceutically acceptable salt thereof, the disease being treated, the mode of administration, and the age, weight, health, and condition of the subject.

[080] In some embodiments, a therapeutically effective amount of the compound or pharmaceutically acceptable salt thereof disclosed herein is administered to the subject (e.g., a human). In some variations of the foregoing, a “therapeutically effective amount” of a compound or pharmaceutically acceptable salt thereof is an amount sufficient to provide a therapeutic benefit in the treatment of a disease, disorder or condition, or to delay or minimize one or more symptoms associated with the disease, disorder or condition. A therapeutically effective amount of a compound or pharmaceutically acceptable salt thereof means an amount of therapeutic agent, alone or in combination with other therapies, which provides a therapeutic benefit in the treatment of the disease, disorder or condition. The term “therapeutically effective amount” can encompass an amount that improves overall therapy, reduces or avoids symptoms or causes of the disease or condition, or enhances the therapeutic efficacy of another therapeutic agent.

[081] In some embodiments, the method provided involves treating a disorder associated with a gain-of-function mutation of KCNT1. In some variations, a “disorder associated with a gain-of- function mutation in KCNT1” refers to a disorder that is associated with, is partially or completely caused by, or has one or more symptoms that are partially or completely caused by, a mutation in KCNT1 that results in a gain-of-function phenotype, i.e., an increase in activity of the potassium channel encoded by KCNT1 resulting in an increase in whole cell current. In some variations, a “gain- of-function mutation of KCNT1” is a mutation in KCNT1 that results in an increase in activity of the potassium channel encoded by KCNT1. Activity can be assessed by, for example, ion flux assay or electrophysiology (e.g., using the whole cell patch clamp technique). Typically, a gain-of-function mutation results in an increase of at least or about 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 125%, 150%, 175%, 200%, 225%, 250%, 275%, 300%, 325%, 350%, 375%, 400%, or more compared to the activity of a potassium channel encoded by a wild-type KCNT1.

IV. Pharmaceutical Compositions and Routes of Administration

[082] Compounds or pharmaceutically acceptable salts thereof provided in accordance with the present disclosure may be administered in the form of pharmaceutical compositions. Therefore, disclosed herein are pharmaceutical compositions that contain, as the active ingredient, one or more of the compounds described, or a pharmaceutically acceptable salt or ester thereof, and one or more of pharmaceutically acceptable excipients, carriers, including inert solid diluents and fillers, diluents, including sterile aqueous solution and various organic solvents, permeation enhancers, solubilizers, and adjuvants. The pharmaceutical compositions may be administered alone or in combination with other therapeutic agents. Such compositions may be prepared in a manner disclosed in the pharmaceutical art, including, for example, in Remington’s Pharmaceutical Sciences, Mace Publishing Co., Philadelphia, Pa. 17th Ed. (1985) and Modern Pharmaceutics, Marcel Dekker, Inc. 3rd Ed. (G. S. Banker & C. T. Rhodes, Eds.).

[083] The pharmaceutical compositions may be administered in either single or multiple doses by any of the accepted modes of administration of agents having similar utilities, for example as described in those patents and patent applications incorporated by reference, including rectal, buccal, intranasal, and transdermal routes, by intra-arterial injection, intravenously, intraperitoneally, parenterally, intramuscularly, subcutaneously, orally, topically, as an inhalant, or via an impregnated or coated device such as a stent, for example, or an artery -inserted cylindrical polymer.

[084] One mode for administration is parenteral, particularly by injection. The forms in which the novel compositions disclosed herein may be incorporated for administration by injection include aqueous or oil suspensions, or emulsions, with sesame oil, com oil, cottonseed oil, or peanut oil, as well as elixirs, mannitol, dextrose, or a sterile aqueous solution, and similar pharmaceutical vehicles. Aqueous solutions in saline are also conventionally used for injection. Ethanol, glycerol, propylene glycol, liquid polyethylene glycol, and the like (and suitable mixtures thereof), cyclodextrin derivatives, and vegetable oils may also be employed. The proper fluidity can be maintained, for example, by the use of a coating, such as lecithin, by the maintenance of the required particle size in the case of dispersions, and by the use of surfactants. The prevention of the action of microorganisms can be brought about by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, sorbic acid, thimerosal, and the like.

[085] Sterile inj ectable solutions are prepared by incorporating a compound or pharmaceutically acceptable salt thereof as disclosed herein in the required amount in the appropriate solvent with various other ingredients as enumerated above, as desired, followed by filtered sterilization. Generally, dispersions are prepared by incorporating the various sterilized active ingredients into a sterile vehicle which contains the basic dispersion medium and the desired other ingredients from those enumerated above. In the case of sterile powders for the preparation of sterile injectable solutions, exemplary methods of preparation include vacuum-drying and freeze-drying techniques which yield a powder of the active ingredient plus any additional desired ingredient from a previously sterile-filtered solution thereof. [086] Oral administration is another route for administration of the compounds or pharmaceutically acceptable salts thereof as disclosed herein. Administration may be via capsule or enteric coated tablets, or the like. In making the pharmaceutical compositions that include at least one compound or pharmaceutically acceptable salt thereof as described herein, the active ingredient may be diluted by an excipient and/or enclosed within such a carrier that can be in the form of a capsule, sachet, paper or other container. When the excipient serves as a diluent, it can be in the form of a solid, semi-solid, or liquid material (as above), which acts as a vehicle, carrier or medium for the active ingredient. Thus, the compositions can be in the form of tablets, pills, powders, lozenges, sachets, cachets, elixirs, suspensions, emulsions, solutions, syrups, aerosols (as a solid or in a liquid medium), ointments containing, for example, up to 10% by weight of the active compound, soft and hard gelatin capsules, sterile injectable solutions, and sterile packaged powders.

[087] Some examples of suitable excipients include lactose, dextrose, sucrose, sorbitol, mannitol, starches, gum acacia, calcium phosphate, alginates, tragacanth, gelatin, calcium silicate, microcrystalline cellulose, polyvinylpyrrolidone, cellulose, sterile water, syrup, and methyl cellulose. In certain embodiments, the compositions disclosed herein can additionally include lubricating agents such as talc, magnesium stearate, and mineral oil; wetting agents; emulsifying and suspending agents; preserving agents such as methyl and propylhydroxy-benzoates; sweetening agents; and flavoring agents.

[088] The compositions disclosed herein can be formulated so as to provide quick, sustained or delayed release of the active ingredient after administration to the patient by employing procedures known in the art. Controlled release drug delivery systems for oral administration include osmotic pump systems and dissolutional systems containing polymer-coated reservoirs or drug-polymer matrix formulations. Examples of controlled release systems are given in U.S. Pat. Nos. 3,845,770; 4,326,525; 4,902,514; and 5,616,345. Another embodiment for use in the methods disclosed herein may employ transdermal delivery devices (“patches”). Such transdermal patches may be used to provide continuous or discontinuous infusion of the compounds or pharmaceutically acceptable salts thereof as disclosed herein in controlled amounts. The construction and use of transdermal patches for the delivery of pharmaceutical agents is described, for example, in U.S. Pat. Nos. 5,023,252, 4,992,445 and 5,001,139. Such patches may be constructed for continuous, pulsatile, or on-demand delivery of pharmaceutical agents.

[089] The compositions disclosed herein may be formulated in a unit dosage form. The term “unit dosage forms” refers to physically discrete units suitable as unitary dosages for human subjects and other mammals, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect, in association with a suitable pharmaceutical excipient (e g., a tablet, capsule, ampoule). The compounds are generally administered in a pharmaceutically effective amount. Preferably, for oral administration, each dosage unit contains from about 1 mg to about 2 g of a compound or pharmaceutically acceptable salt thereof as described herein, and for parenteral administration, preferably from about 0.1 mg to about 700 mg of a compound or pharmaceutically acceptable salt thereof as described herein. It will be understood, however, that the amount of the compound or pharmaceutically acceptable salt thereof actually administered usually will be determined by a physician, in the light of the relevant circumstances, including the condition to be treated, the chosen route of administration, the actual compound or pharmaceutically acceptable salt thereof administered and its relative activity, the age, weight, and response of the individual patient, the severity of the patient’s symptoms, and the like.

[090] For preparing solid compositions such as tablets, the principal active ingredient may be mixed with a pharmaceutical excipient to form a solid preformulation composition containing a homogeneous mixture of a compound or pharmaceutically acceptable salt thereof as disclosed herein. When referring to these preformulation compositions as homogeneous, it is meant that the active ingredient is dispersed evenly throughout the composition so that the composition may be readily subdivided into equally effective unit dosage forms such as tablets, pills, and capsules.

[091] The tablets or pills disclosed herein may be coated or otherwise compounded to provide a dosage form affording the advantage of prolonged action, or to protect from the acid conditions of the stomach. For example, the tablet or pill can comprise an inner dosage and an outer dosage component, the latter being in the form of an envelope over the former. The two components can be separated by an enteric layer that serves to resist disintegration in the stomach and permit the inner component to pass intact into the duodenum or to be delayed in release. A variety of materials can be used for such enteric layers or coatings, such materials including a number of polymeric acids and mixtures of polymeric acids with such materials as shellac, cetyl alcohol, and cellulose acetate.

[092] Compositions for inhalation or insufflation include solutions and suspensions in pharmaceutically acceptable, aqueous or organic solvents, or mixtures thereof, and powders. The liquid or solid compositions may contain suitable pharmaceutically acceptable excipients as described herein. In certain embodiments, the compositions are administered by the oral or nasal respiratory route for local or systemic effect. Compositions in pharmaceutically acceptable solvents may be nebulized by use of inert gases. Nebulized solutions may be inhaled directly from the nebulizing device, or the nebulizing device may be attached to a facemask tent or intermittent positive pressure breathing machine. Solution, suspension, or powder compositions may be administered, such as orally or nasally, from devices that deliver the formulation in an appropriate manner.

[093] In some embodiments, there is provided a pharmaceutical composition comprising a compound, or pharmaceutically acceptable salt thereof, as disclosed herein and at least one pharmaceutically acceptable excipient and/or carrier.

[094] Those skilled in the art will recognize or be able to ascertain using no more than routine experimentation many equivalents to the specific embodiments described herein. The scope of the present embodiments described herein is not intended to be limited to the above Description or the Examples that follow, but rather is as set forth in the appended claims. Those of ordinary skill in the art will appreciate that various changes and modifications to this description may be made without departing from the spirit or scope of the embodiments disclosed herein, as defined in the claims.

EXAMPLES

[095] In order that the embodiments described herein may be more fully understood, the following examples are set forth. The synthetic and biological examples described in this application are offered to illustrate the compounds, pharmaceutical compositions, and methods provided herein and are not to be construed in any way as limiting their scope.

[096] The compounds provided herein can be prepared from readily available starting materials using the following general methods and procedures. It will be appreciated that where typical or preferred process conditions (i.e., reaction temperatures, times, mole ratios of reactants, solvents, pressures, etc.) are given, other process conditions can also be used unless otherwise stated. Optimal reaction conditions may vary with the particular reactants or solvent used, but such conditions can be determined by one skilled in the art by routine optimization.

[097] Additionally, as will be apparent to those skilled in the art, conventional protecting groups may be necessary to prevent certain functional groups from undergoing undesired reactions. The choice of a suitable protecting group for a particular functional group as well as suitable conditions for protection and deprotection are described in the art. For example, numerous protecting groups, and their introduction and removal, are described in T. W. Greene and P. G. M. Wuts, Protecting Groups in Organic Synthesis, Second Edition, Wiley, New York, 1991, and references cited therein. [098] The compounds provided herein may be isolated and purified by known standard procedures. Such procedures include recrystallization, filtration, flash chromatography, trituration, high performance liquid chromatography (HPLC), or supercritical fluid chromatography (SFC). Note that flash chromatography may either be performed manually or via an automated system. The compounds provided herein may be characterized by known standard procedures, such as nuclear magnetic resonance spectroscopy (NMR) or liquid chromatography mass spectrometry (LCMS). NMR chemical shifts are reported in part per million (ppm) and are generated using methods described in the art.

[099] Abbreviations

ACN Acetonitrile

AcOH Acetic acid

DCE Dichloroethane

DCM Dichloromethane

DIPEA N,N-Diisopropylethylamine

DMF Dimethylformamide

DMSO Dimethylsulfoxide

DMSO-d6 Deuterated dimethylsulfoxide-d6

Et3N Triethylamine EtOAc Ethyl acetate

HATU 2-(7-Azabenzotriazol- 1 -yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate

MeOH Methanol

NBS N-bromosuccinimide

TFA Trifluoroacetic acid

THF Tetrahydrofuran.

Example 1: Characterization of Exemplary Compounds

[0100] Compounds were characterized by numerous methods known in the art and as described below.

[0101] KCNT1 - Patch Clamp Assay: Inhibition of KCNT1 (KNal.l, Slack) was evaluated using a tetracycline inducible cell line (HEK-TREX). Currents were recorded using the SyncroPatch 384PE automated, patch clamp system. Pulse generation and data collection were performed with PatchController384 VI.3.0 and DataController384 VI.2.1 (Nanion Technologies). The access resistance and apparent membrane capacitance were estimated using built-in protocols. Current were recorded in perforated patch mode (10 pM escin) from a population of cells. The cells were lifted, triturated, and resuspended at 800,000 cells/ml. The cells were allowed to recover in the cell hotel prior to experimentation. Currents were recorded at room temperature. The external solution contained the following (in mM): NaCl 105, NMDG 40, KC1 4, MgCh 1, CaCh 5, and HEPES 10 (pH = 7.4, Osmolarity -300 mOsm). The extracellular solution was used as the wash, reference, and compound delivery solution. The internal solution contained the following (in mM): NaCl 70, KF 70, KC1 10, EGTA 5, HEPES 5, and Escin 0.01 (pH = 7.2, Osmolarity -295 mOsm). Escin is made at a 5 mM stock in water, aliquoted, and stored at -20 °C. The compound plate was created at 2x concentrated in the extracellular solution. The compound was diluted to 1:2 when added to the recording well. The amount of DMSO in the extracellular solution was held constant at the level used for the highest tested concentration. A holding potential of -80 mV with a 100ms step to OmV was used. Mean current was measured during the step to 0 mV. 100 pM Bepridil was used to completely inhibit KCNT1 current to allow for offline subtraction of non-KCNTl current. The average mean current from 3 sweeps was calculated, and the percent inhibition of each compound was calculated. The percent inhibition as a function of the compound concentration was fit with a Hill equation to derive IC50, slope, minimum parameters, and maximum parameters. If KCNT1 inhibition was less than 50% at the highest tested concentration or if an IC50 could not be calculated, then a percent inhibition was reported in place of the IC50.

[0102] Results from this example are summarized in Table 1. In this table, “A” indicates IC50 of less than or equal to 1 pM; “B” indicates inhibition of between 1 pM to 20 pM; and “C” indicates inhibition of greater than or equal to 20 pM

Table 1.

[0103] Pharmacokinetics: Pharmacokinetic data was obtained for compounds of Formula (I) and

Formula (II) as detailed herein.

[0104] Kinetic Solubility Assay: The Kinetic solubility assay employed the shake flask method followed by HPLC-UV analysis.

[0105] The following step-wise procedure was used:

1) Weigh and dissolve the samples in 100% DMSO as the stock solution of 10 mM. About 10 pL (compound/Media) of stock solution is needed in this assay.

2) Add the test compounds and controls (10 mM in DMSO, 10 pL/vial) into the 50 mM pH 7.4 phosphate buffer (490 pL/well) placed in a Mini-Uniprep filter. 3) Vortex the samples of kinetic solubility for 2 minutes.

4) Incubate and shake the solubility solutions on an orbital shaker with 800 rpm at room temperature for 24 hours.

5) Centrifuge at 4000 rpm, 20°C for 10 minutes.

6) Transfer 400 uL (with or without dilution) of each solubility supernatant into 96-deep well for analysis after the samples will be directly filtered by the syringeless filter device.

7) Determine the test compound concentration of the filtrate using HPLC-UV.

8) Inject at least 5 UV standard solutions into HPLC from low to high concentration subsequently and then test the Kinetic solubility supernatant in duplicate.

9) Use the QC samples to monitor Kinetic solubility determination process.

[0106] Log D The Log D assay is a miniaturized 1-octanol/buffer shake flask method followed by LC/MS/MS analysis. It is typically measured by determining the partition of a compound between an organic solvent (1 -octanol) and an aqueous buffer (0.1 M phosphate buffer, pH 7.4; Varied buffer pH can be set). Since logD is pH dependent, the pH of the aqueous phase is always specified and is commonly measured at pH 7.4, the physiological pH of body fluids. The following Log D method was used to calculate the Log D values in Table 8 below:

1) Dissolve appropriate test compounds in 100% DMSO to 10 mM solutions.

2) Transfer the test compounds (10 mM in DMSO; 2 pL/well) and QC samples (10 mM in DMSO; 2 pL/well) from storage tubes to the 96-well polypropylene cluster tubes.

3) Add Buffer- saturated 1-octanol (149 pL/well) and 1-octanol saturated buffer (149 pL/well) to the well, respectively.

4) Vigorously mix each of the tubes on their sides for 3 minutes and then shake at a speed of 880 rpm at room temperature for 1 hour.

5) Centrifuge the tubes at 4000 rpm for 5 minutes. 6) Dilute the sample of buffer layer by a factor of 20 fold and the sample of 1 -octanol layer by a factor of 200 fold with internal standard (IS) solution. Note: the dilution factor is mainly based on the properties of the compound.

7) Analyze the sample using a triple quadrupole mass spectrometer. Correct the peak areas by dilution factors and embedded internal standard, and the ratio of the corrected peak areas will be used to calculate the results (Log D value).

8) Use the QC samples to monitor the process Log D determination.

9) Data Analysis: The Log D value for each compound is calculated by the following equation:

[0107] Different dilution value in the equation will be performed with different dilution factor for sample handling.

[0108] MW, XLogPand TPSA These data points were all calculated using Dotmatics.

[0109] Liver Microsome Metabolic Stability Assay (NADPH) :

1) Test compounds were incubated at 37°C with liver microsomes (pooled from multiple donors) at 1.0 pM in the presence of NADPH (~1.0 mM) at 0.5 mg/ml microsomal protein.

2) Positive controls include testosterone (3A4 substrate), propafenone (2D6) and diclofenac (2C9). They are also incubated with microsomes in the presence of NADPH.

3) Time samples (0, 5, 15, 30, 45 and 60 minutes) are removed and immediately mixed with cold acetonitrile containing internal standard (IS). Test compound incubated with microsomes without NADPH for 60 min are also included.

4) Duplicate point for each test condition (n=2).

5) Samples are analyzed by LC/MS/MS; disappearance of test compound is assessed base on peak area ratios of analyte/IS (no standard curve). 6) An excel data summary, calculated intrinsic clearance and Tl/2 values are provided.

7) The following equation is used to calculate the microsome clearance:

The mg microsomal protein / g liver weight is 45 for 5 species. The liver weight values will use 40 g/kg, 30 g/kg, 32 g/kg, 20 g/kg and 88 g/kg for rat, monkey, dog, human and mouse, respectively. The liver clearance will be calculated using CLint(mic) with the following equation:

[OHl] Results from this example are summarized in Table 2 below.

Table 2.

Example 2 - Synthesis of (/ -\-(5-chloro-2.3-dihydro-l//-inden-l-yl)-2.3- dihydrobcnzo[d]isothiazole-6-carboxamide 1,1-dioxide (Compound Ill-a) Step 1: Synthesis of 2,3-dihydrobenzo[d]isothiazole-6-carboxylic acid 1,1-dioxide (2)

[0112] To compound 1 (0.5 g, 1.499 mmol) in a sealed tube was added TFA (1.0 mL), and the reaction mixture was stirred at room temperature for 2 hours. After completion of the reaction (monitored by TLC), the reaction mixture was concentrated under reduced pressure. The crude obtained was triturated with pentane. The obtained solid was filtered off, and the solid was dried over vacuo to afford the title compound 2 (0.25 g, crude) as an off-white solid.

[0113] Step 2: Synthesis of (/)-\-(5-chloro-2.3-dihydro-l//-inden-l-yl)-2.3- dihydrobenzo[<Z]isothiazole-6-carboxamide 1,1-dioxide (Compound Ill-a)

[0114] To a stirred solution of compound 2 (0.20 g, 0.938 mmol) in DCM (5 mL) were added

DIPEA (0.4 mL, 2.617 mmol) and HATU (0.49 g, 1.308 mmol) at 0 °C. To this solution, compound 3 (0.29 g, 1.465 mmol) was added, and the reaction mixture was stirred at room temperature for 2 hours. After completion of the reaction (monitored by TLC), the reaction mixture was diluted with water and extracted with EtOAc. The combined organic layers were washed with water followed by brine, dried over anhydrous Na2SC>4, and concentrated under reduced pressure. The crude compound was purified by Combi-Flash chromatography (eluting with 40-50% EtOAc in heptane) to afford the title Compound IILa (32 mg, 0.086 mmol, 9% yield) as an off-white solid.

[0115] Data: HPLC: Rt 6.37 min, 98.56%. Column: X-Select CSH C18 (4.6*150) mm 5u; Mobile Phase: A - 0.1% TFA in water; B - Acetonitrile; Inj Volume; 5.0_L, Flow Rate: 1.2. mL/minute; Gradient program: Time(min)/ B Cone. : 0.01/5, 1.0/5, 5.0/100, 12.0/100, 14.0/5, 18.0/5. Chiral HPLC: Rt 9.77 min, 100. Column: CHIRAL PAK IG (250*4.6mm,5um); Mobile phase: A: 0.1%DEA in n-Hexane; Mobile phase: B: DCM:MEOH(50:50); A:B :80:20; Flow :1.0 ml/min. LCMS : 362.85 (M+H), Rt 1.98 min, 99.17%. Column: X-Select CSH C18 (3.0*50) mm 2.5um Mobile Phase: A: 0.05% Formic acid in water: ACN (95:5) B: 0.05% Formic acid in ACN Inj Volume: 2.0pL, Column oven temperature: 50 C Flow Rate: 1.2. mL/minute Gradient program: 0% B to 98 % B in 2.0 minute, hold till 3.0 min, at 3.2 min B cone is 0 % up to 4.0 min. ¹H NMR (400 MHz, DMSO-rfe) 69.05 (d, J= 8.1 Hz, 1H), 8.33 (s, 1H), 8.20 (dd, J= 1.4, 8.1 Hz, 1H), 7.95 (t, J= 4.7 Hz, 1H), 7.67 (d, .7= 8.1 Hz, 1H), 7.35 (s, 1H), 7.28 (d, J= 8.1 Hz, 1H), 7.26 - 7.21 (m, 1H), 5.52 (q, J= 8.0 Hz, 1H), 4.47 (d, J= 4.6 Hz, 2H), 3.07 - 2.96 (m, 1H), 2.92 - 2.82 (m, 1H), 2.09 - 1.96 (m, 1H), [One proton merged in solvent peak].

Example 3 - Synthesis of V-((/?)-5-chl()io-2.3-dihydro-l//-inden-l-yl)-3-nielhyl-2.3- dihydrobenzo[</]isothiazole-6-carboxamide 1,1-dioxide (Compound Ill-b)

Step 1: Synthesis of 6-bromo-3-methylbenzo[</]isothiazole 1,1-dioxide (2)

[0116] To a stirred solution of compound 1 (2.0 g, 7.631 mmol) in THF (10 mL) was added MeMgCl (3.0 M in THF, 5.0 mL, 15.263 mmol) drop-wise at 0 °C, and the reaction mixture was stirred at room temperature for 16 hours. After completion of the reaction (monitored by TLC), the reaction mixture was concentrated over reduced pressure. The crude compound was diluted with water, acidified with Cone. HC1, and stirred for 10 minutes. The obtained precipitate was filtered off and solid was dried over vacuo to afford the title compound 2 (1.8 g, 4.567 mmol, 59.8% yield) as a pale brown solid.

Step 2: Synthesis of 6-bromo-3-methyl-2,3-dihydrobenzo[<Z]isothiazole 1,1-dioxide (3)

[0117] To a stirred solution of compound 2 (1.8 g, 6.920 mmol) in methanol (20 mL) was added NaBH₄ (0.78 g, 20.76 mmol) at 0 °C. The reaction mixture was stirred at room temperature for 3 hours. After completion of the reaction (monitored by TLC), the reaction mixture was diluted with water and extracted with EtOAc. The combined organic layers were washed with water followed by brine, dried over anhydrous Na2SC>4, and concentrated under reduced pressure. The crude compound was purified by Combi-Flash chromatography (eluting with 30-40% EtOAc in heptane) to afford the title compound 3 (0.4 g, 1.327 mmol, 19.18% yield) as an off-white solid.

Step 3: Synthesis of 6-bromo-2-(4-methoxybeiizyl)-3-methyl-2,3-dihydrobenzo[<Z]isothiazole 1,1-dioxide (4)

[0118] To a stirred solution of compound 3 (0.4 g, 1.526 mmol) in DMF (5 mL), were added CS2CO3 (1.2 g, 3.815 mmol) and para-methoxy benzyl chloride (0.27 mL, 1.983 mmol) at 0 °C. The reaction mixture was stirred at 120 °C for 3 hours. After completion of the reaction (monitored by TLC), the reaction mixture was diluted with water and extracted with EtOAc. The combined organic layers were washed with water followed by brine, dried over anhydrous Na2SO4, and concentrated under reduced pressure. The crude compound was purified by Combi-Flash chromatography (eluting with 30-40% EtOAc in heptane) to afford the title compound 4 (0.4 g, 0.397 mmol, 26% yield) as an off-white solid.

Step 4: Synthesis of ethyl 2-(4-methoxybenzyl)-3-methyl-2,3-dihydrobenzo[<Z|isothiazole-6- carboxylate 1,1-dioxide (5)

[0119] To a stirred solution of compound 4 (0.4 g, 1.046 mmol) in DMF:ethanol (2.5:1 mL) were added Et3N (0.4 mL, 3.139 mmol), palladium acetate (23.48 mg, 0.104 mmol) and followed by (Ph3P)2Propane (86.2 mg, 0.209 mmol). The reaction mixture was purged under nitrogen for 10 minutes and stirred at 80 °C under carbon monoxide gas (100 psi) for 16 hours. After completion of the reaction (monitored by TLC), the reaction mixture was cooled to room temperature, diluted with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure. The crude compound was purified by Combi-Flash chromatography (eluting with 50-60% ethyl acetate in heptane) to afford the title compound 5 (0.15 g, 0.323 mmol, 38.2% yield) as an off-white solid. Step 5: Synthesis of 2-(4-methoxybenzyl)-3-methyl-2,3-dihydrobenzo[</]isothiazole-6- carboxylic acid 1,1-dioxide (6)

[0120] To a stirred solution of compound 5 (0.15 g, 0.399 mmol) in TffivFLO (4: 1 mL) was added LiOH.FEO (0.05 g, 1.198 mmol) at 0 °C, and the reaction mixture was stirred at room temperature for 16 hours. After completion of the reaction (monitored by TLC), the reaction mixture was cooled to room temperature and concentrated under reduced pressure to remove the solvent effluents. The obtained crude compound was diluted with water, acidified with IN HC1, and extracted with DCM. The combined organic layers were washed with brine, dried over anhydrous Na2SC>4, filtered and concentrated under reduced pressure. The crude compound was purified by Combi-Flash chromatography (eluting with 5% MeOH in DCM) to afford the title compound 6 (0.11 g, 0.291 mmol, 72.9% yield) as an off-white solid.

Step 6: Synthesis of 3-methyl-2-(2,2,2-trifluoroacetyl)-2,3-dihydro-214-benzo[<f]isothiazole-6- carboxylic acid 1,1-dioxide (7)

[0121] Compound 6 (0.11 g, 0.316 mmol) in TFA (0.2 mL, 1.583 mmol) was stirred at 130 °C for 2 hours. After completion of the reaction (monitored by TLC), the reaction mixture was cooled to room temperature and concentrated under reduced pressure to afford the title compound 7 (0.08 g, crude) as a pale yellow solid.

Step 7: Synthesis of \-( (/?)-5-chloro-2.3-dihydro-l //-inden- 1 -yl)-3-nielhy 1-2.3- dihydrobenzo[</]isothiazole-6-carboxamide 1,1-dioxide (Compound Ill-b)

[0122] To a stirred solution of compound 7 (0.08 g, 0.234 mmol) in DCM (5 mL) were added DIPEA (0.1 mL, 0.586 mmol) and HATU (0.11 g, 0.304 mmol) at 0 °C. After 10 minutes, compound 8 (0.057 g, 0.281 mmol) was added to the solution, and the reaction mixture was stirred at room temperature for 1 hour. After completion of the reaction (monitored by TLC), the reaction mixture was diluted with water and extracted with DCM. The combined organic layers were washed with water followed by brine, dried over anhydrous Na2SO4, and concentrated under reduced pressure. The crude compound was purified by Combi-Flash chromatography (eluting with 40-45% EtOAc in heptane) to afford the title Compound Ill-b (23 mg, 0.06 mmol, 25.9% yield) as an off-white solid. [0123] Data: HPLC: Rt 8.082 min, 99.6%. Column: X-Bridge C18 (4.6*150) mm 5u Mobile Phase: A - 5mM Ammonium bicarbonate in water B - Acetonitrile Inj Volume; 5.0pL, Flow Rate: 1.0 mL/minute Gradient program: Time(min)/ B Cone. : 0.01/5, 1.0/5, 8.0/100, 12.0/100, 14.0/5, 18.0/5. LCMS : 377.00 (M+H), Rt 1.761 min, 99.89%. Column: X-Bridge CSH (3.0*50) mm 2.5 p Mobile Phase: A: 0.05% Formic acid in water: ACN (95:5) B: 0.05% Formic acid in ACN Inj Volume: 2.0pL Flow Rate : 1.2. mL/minute Column oven temperature: 50 C Gradient program: 0% B to 98 % B in 2.0 min, hold till 3.0 min, at 3.2 min B cone is 0 % up to 4.0 min. ’H NMR (400 MHz, DMSO- d6) 89.04 (d, .7= 7.6 Hz, 1H), 8.30 (d, J= 1.6 Hz 1H), 8.21 (d, J= 8.3 Hz, 1H), 8.06 (br s, 1H), 7.73 (d, J= 8.3 Hz, 1H), 7.35 (s, 1H), 7.30 - 7.21 (m, 2H), 5.52 (q, J= 7.7 Hz, 1H), 4.77 (q, J = 6.8 Hz, 1H), 3.05 - 2.97 (m, 1H), 2.92 - 2.79 (m, 1H), 2.08 - 1.95 (m, 1H), 1.47 (d, J= 6.4 Hz, 3H).

Example 4 - Synthesis of (/?)-\-(5-chloro-2,3-dihydro-l//-inden-l-yl)-5-inethoxy-2,3- dihydrobenzo[</]isothiazole-6-carboxamide 1,1-dioxide (Compound III-c)

Step 1: Synthesis of 5-bromo-4-fluoro-2-methylbenzenesulfonyl chloride (2)

[0124] To compound 1 (4.03 mL, 31.743 mmol) was added chlorosulfonic acid (5.9 mL, 89.08 mmol) drop-wise at 0 °C, and the reaction mixture was stirred at room temperature for 1 hour. After completion of the reaction (monitored by TLC), the reaction mixture was poured into ice cold water and extracted with EtOAc The combined organic layers were washed with water followed by brine, dried over anhydrous Na2SC>4, and concentrated under reduced pressure to afford the title compound 2 (6.0 g, crude) as a grey solid.

Step 2: Synthesis of 5-bronio-\-(tert-biityl)-4-niioro-2-niethylbenzenesuironainide (3)

[0125] To a stirred solution of compound 2 (3 g, 10.434 mmol) in DCM (30 mL) was added t-BuNH2 (3.4 mL, 31.301 mmol). The reaction mixture stirred at room temperature for 16 hours. After completion of the reaction (monitored by TLC), the reaction mixture was concentrated under reduced pressure. The crude compound was triturated with water, the solid was filtered and dried over vacuo to afford the title compound 3 (3.0 g, crude) as an off-white solid.

Step 3: Synthesis of 5-bromo-2-(bromomethyl)-A-(tert-butyl)-4-fluorobenzenesulfonamide (4)

[0126] To a stirred solution of compound 3 (3 g, 9.253 mmol) in CCL (30 mL) were added NBS (1.65 g, 9.253 mmol) and benzoyl peroxide (0.22 g, 0.925 mmol) and degassed with Argon gas for 5 minutes. The reaction mixture was stirred at 80 °C for 16 hours. After completion of the reaction (monitored by TLC), the reaction mixture was cooled to room temperature and concentrated under reduced pressure. The crude compound was purified by Combi-Flash chromatography (eluting with 30-40% EtOAc in heptane) to afford the title compound 4 (2.5 g, 5.705 mmol, 61.6% yield) as an off- white solid.

Step 4: Synthesis of 6-bromo-2-(tert-butyl)-5-fluoro-2,3-dihydrobenzo[d]isothiazole 1,1- dioxide (5)

[0127] To a stirred solution of compound 4 (2.0 g, 4.961 mmol) in DMF (20 mL) was added NaH (0.15 g, 6.449 mmol) at 0 °C. The reaction mixture was stirred at room temperature for 12 hours. After completion of the reaction (monitored by TLC), the reaction was diluted with water and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure. The crude compound was purified by Combi-Flash chromatography (eluting with 40-50% EtOAc in heptane) to afford the title compound 5 (1.0 g, 3.072 mmol, 61.9% yield) as an off-white solid.

Step 5: Synthesis of 6-bromo-2-(tert-butyl)-5-methoxy-2,3-dihydrobenzo[J|isothiazole 1,1- dioxide (6) [0128] To a stirred solution of compound 5 (0.5 g, 1.551 mmol) in methanol (5mL) was added NaOMe (0.25 g, 4.655 mmol) at 0 °C. The reaction mixture was stirred at 80 °C for 12 hours. After completion of the reaction (monitored by TLC), the reaction was cooled to room temperature, diluted with water, and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure. The crude compound was purified by Combi-Flash chromatography (eluting with 30-45% EtOAc in heptane) to afford the title compound 6 (0.5 g, 1.451 mmol, 93.5% yield) as an off-white solid.

Step 6: Synthesis of ethyl 2-(tert-butyl)-5-methoxy-2,3-dihydrobenzo[<Z]isothiazole-6- carboxylate 1,1-dioxide (7)

[0129] To a stirred solution of compound 6 (0.2 g, 0.598 mmol) in DMF:ethanol (2:4 mL) were added Et3N (0.25 mL, 1.795 mmol) and palladium acetate (13.4 mg, 0.059 mmol), followed by (Ph3P)2Propane (49.3 mg, 0.119 mmol). The reaction mixture was purged under nitrogen for 10 minutes and stirred at 80 °C under carbon monoxide gas (100 psi) for 16 hours. After completion of the reaction (monitored by TLC), the reaction mixture was cooled to room temperature, diluted with water, and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure. The crude compound was purified by Combi-Flash chromatography (eluting with 50-60% ethyl acetate in heptane) to afford the title compound 7 (0.05 g, 0.145 mmol, 24.2% yield) as an off-white solid.

[0130] Step-7: Synthesis of 2-(tert-butyl)-5-methoxy-2,3-dihydrobenzo[ ]isothiazole-6- carboxylic acid 1,1-dioxide (6)

[0131] To a stirred solution of compound 7 (0.56 g, 1.710 mmol) in TFEvFEO (4: 1 mL) was added LiOH.FEO (0.21 g, 5.131 mmol) at 0 °C, and the reaction mixture was stirred at room temperature for 12 hours. After completion of the reaction (monitored by TLC), the reaction mixture was concentrated under reduced pressure to remove the solvent effluents. The obtained crude compound was diluted with water, acidified with IN HC1, and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure to afford the title compound 8 (0.4 g, crude) as an off-white solid. [0132] Step 8: Synthesis of (/?)-2-(tert-butyl)-\-(5-chloro-2.3-dihydro-l//-inden-l-yl)-5- methoxy-2,3-dihydrobenzo[d]isothiazole-6-carboxamide 1,1-dioxide (10)

[0133] To a stirred solution of compound 8 (0.11 g, 0.367 mmol) in DCM (10 mL) were added DIPEA (0.19 mL, 1.102 mmol) and HATU (0.2 g, 0.551 mmol) at 0 °C. After 10 minutes, compound 9 (0.082 g, 0.404 mmol) was added to the solution, and the reaction mixture was stirred at room temperature for 1 hour. After completion of the reaction (monitored by TLC), the reaction mixture was diluted with water and extracted with DCM. The combined organic layers were washed with water followed by brine, dried over anhydrous Na2SO4, and concentrated under reduced pressure. The crude compound was purified by Combi-Flash chromatography (eluting with 40-45% EtOAc in heptane) to afford the title compound 10 (0.11 g, 0.225 mmol, 61.3% yield) as an off-white solid.

Step 9: Synthesis of (/?)-V-(5-chloro-2.3-dihydro-l//-inden-l-yl)-5-niethoxy-2.3- dihydrobenzo[<Z]isothiazole-6-carboxamide 1,1-dioxide (Compound III-c)

[0134] Compound 10 (0.1 g, 0.222 mmol) in TFA (1 mL, 7,095 mmol) was stirred at room temperature for 6 hours. After completion of the reaction (monitored by TLC), the reaction mixture was concentrated under reduced pressure. The crude compound was diluted with EtOAc and washed with saturated NaHCOs solution. The combined organic layers were washed with water followed by brine, dried over anhydrous Na2SO4, and concentrated under reduced pressure. The crude compound was purified by Combi-Flash chromatography (eluting with 40-45% EtOAc in heptane) to afford the title Compound III-c (12 mg, 0.030 mmol, 13.6% yield) as an off-white solid.

[0135] Data: HPLC: Rt 6.636 min, 99.541 %. Column: X-Select CSH C18 (4.6* 150) mm 3.5p) Mobile Phase: A - 0.1% Formic acis in water B - Acetonitrile Inj Volume; 5.0pL, Flow Rate: 1.0 mL/minute Gradient program: Time (min)/ B Cone.: 0.01/5, 1.0/5, 8.0/100, 12.0/100, 14.0/5, 18.0/5. LCMS : 392.85 (M+H), Rt 1.699 min, 97.22%. Column: X-Select CSH (3.0*50) mm 2.5u Mobile Phase: A: 0.05% Formic acid in water: ACN (95:5) B: 0.05% Formic acid in ACN Inj Volume: 2.0pL Flow Rate: 1.2 mL/minute Column oven temperature: 50 C Gradient program: 0% B to 98 % B in 2.0 min, hold till 3.0 min, at 3.2 min B cone is 0 % up to 4.0 min. ’H NMR (400 MHz, DMSO- (16) 5 = 8.61 (d, J= 8.3 Hz, 1H), 7.85 (s, 1H), 7.78 (t, J = 4.9 Hz, 1H), 7.32 (d, J = 7.3 Hz, 2H), 7.28 - 7.25 (m, 2H), 5.50 - 5.43 (m, 1H), 4.39 (d, J= 5.4 Hz, 2H), 3.89 (s, 3H), 3.13 - 2.77 (m, 3H), 2.01 - 1.89 (m, 1H).

Claims

CLAIMS What is claimed is:

1. A compound of Formula (III) having a sulfonamide core:

or a pharmaceutically acceptable salt thereof, wherein:

X is chosen from -C- or -N-;

Ri is chosen from -H or an alkyl;

R2 is chosen from -H, an alkyl, an alkoxy, or a halogen;

R3 is chosen from -H, an alkyl, or a halogen; and n is 1 or 2.

2. The compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein X is -C-.

3. The compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein X is -N-.

4. The compound of any one of claims 1-3, or a pharmaceutically acceptable salt thereof, wherein Ri is chosen from -H or -CH3.

5. The compound of any one of claims 1-4, or a pharmaceutically acceptable salt thereof, wherein n is 1.

6. The compound of any one of claims 1-4, or a pharmaceutically acceptable salt thereof, wherein n is 2.

7. The compound of any one of claims 1-6, or a pharmaceutically acceptable salt thereof, wherein R2 is chosen from -H, -OCH3, or -F.

8. The compound of any one of claims 1-7, or a pharmaceutically acceptable salt thereof, wherein R3 is -Cl.

9. The compound of claim 1, wherein the compound is chosen from any of the following compounds or enantiomers thereof, or a pharmaceutically acceptable salt thereof:

A pharmaceutical composition, comprising: a compound of any one of claims 1 to 9, or a pharmaceutically acceptable salt thereof; and at least one pharmaceutically acceptable excipient.

11. A method of treating a neurological disorder, a disorder associated with excessive neuronal excitability, or a disorder associated with a gain-of-function mutation of a gene, wherein the method comprises administering to a subject in need thereof an effective amount of a compound of any one of claims 1 to 9, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition of claim 10.

12. The method of claim 11, which is a method of treating a disorder associated with a gain-of- function mutation of KCNT1.

13. The method of claim 10 or 11, wherein the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is epilepsy, an epilepsy syndrome, or an encephalopathy.

14. The method of claim 10 or 11, wherein the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is a genetic or pediatric epilepsy or a genetic or pediatric epilepsy syndrome.

15. The method of claim 10 or 11, wherein the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is a cardiac dysfunction.

16. The method of claim 10 or 11, wherein the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is chosen from epilepsy and other encephalopathies (e.g., malignant migrating focal seizures of infancy (MMFSI) or epilepsy of infancy with migrating focal seizures (EIMFS), autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), West syndrome, infantile spasms, epileptic encephalopathy, focal epilepsy, Ohtahara syndrome, developmental and epileptic encephalopathy, and Lennox-Gastaut syndrome), seizures (e.g., Generalized tonic clonic seizures, Asymmetric Tonic Seizures), leukodystrophy, leukoencephalopathy, intellectual disability, Multifocal Epilepsy, drug-resistant epilepsy, Temporal lobe epilepsy, or cerebellar ataxia.

17. The method of claim 10 or 11, wherein the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is chosen from cardiac arrhythmia, Brugada syndrome, and myocardial infarction.

18. The method of claim 10 or 11, wherein the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is selected from pain and related conditions (e.g., neuropathic pain, acute/chronic pain, migraine).

19. The method of claim 10 or 11, wherein the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is a muscle disorder (e.g., myotonia, neuromyotonia, cramp muscle spasms, spasticity).

20. The method of claim 10 or 11, wherein the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is chosen from itch and pruritis, ataxia, or cerebellar ataxias.

21. The method of claim 10 or 11, wherein the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is a psychiatric disorder (e.g., major depression, anxiety, bipolar disorder, schizophrenia).

22. The method of claim 10 or 11, wherein the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is chosen from a learning disorder, Fragile X, neuronal plasticity, or an autism spectrum disorder.

23. The method of claim 10 or 11, wherein the neurological disorder, the disorder associated with excessive neuronal excitability, or the disorder associated with a gain-of-function mutation of a gene (e.g., KCNT1) is chosen from epileptic encephalopathy with SCN1A, SCN2A, and/or SCN8A mutations, early infantile epileptic encephalopathy, Dravet syndrome, Dravet syndrome with SCN1A mutation, generalized epilepsy with febrile seizures, intractable childhood epilepsy with generalized tonic-clonic seizures, infantile spasms, benign familial neonatal-infantile seizures, SCN2A epileptic encephalopathy, focal epilepsy with SCN3A mutation, cryptogenic pediatric partial epilepsy with SCN3A mutation, SCN8A epileptic encephalopathy, Rasmussen encephalitis, malignant migrating partial seizures of infancy, autosomal dominant nocturnal frontal lobe epilepsy, KCNQ2 epileptic encephalopathy, or KCNT1 epileptic encephalopathy.