WO2007000392A2

WO2007000392A2 - Chloro-substituted guanidines

Info

Publication number: WO2007000392A2
Application number: PCT/EP2006/063267
Authority: WO
Inventors: Alexander Alanine; Luca Claudio Gobbi; Sabine Kolczewski; Thomas Luebbers; Jens-Uwe Peters; Lucinda Steward
Original assignee: F Hoffmann La Roche AG
Current assignee: F Hoffmann La Roche AG
Priority date: 2005-06-27
Filing date: 2006-06-16
Publication date: 2007-01-04
Anticipated expiration: 2007-12-27
Also published as: KR20080014080A; JP4769866B2; BRPI0614032A2; JP2008543962A; US7790732B2; KR100950630B1; CN101208309B; IL188109A0; EP1899306A2; EP1899306B1; AU2006263924A1; CA2612460A1; ES2314940T3; US20060293349A1; CN101208309A; MX2007015778A; WO2007000392A3; ATE411299T1; DE602006003225D1

Abstract

The present invention relates to compounds of formula wherein R1 is hydrogen or halogen; R2 is lower alkyl; R3 is hydrogen, lower alkyl, -(CH2)n-cycloalkyl, -(CH2)n-phenyl optionally substituted by halogen, or is lower alkyl substituted by halogen, or is -(CH2)n-heterocyclyl, -(CH2)nN-di-lower alkyl, -(CH2)nNHC(O)-lower alkyl, adamantly or -(CH2)n-O-lower alkyl; n is 0, 1, 2 or 3; and pharmaceutically acceptable acid addition salts and tautomers thereof. It has been found that the compounds of formula I have a good activity on the 5-HT5A receptor. Therefore, the invention provides the use of a compound of formula I or a pharmaceutically acceptable salt thereof for the treatment of diseases, related to this 15 receptor.

Description

CHLORO-SUBSTITUTED GUANIDINES

The present invention relates to compounds of formula

wherein R¹ is hydrogen or halogen;

R² is lower alkyl;

R³ is hydrogen, lower alkyl, -(CH₂)_n-cycloalkyl, -(CH₂)_n-phenyl optionally substituted by halogen, or is lower alkyl substituted by halogen, or is -(CH₂)_n-heterocyclyl, -(CH₂)_nN-di-lower alkyl, -(CH₂)_nNHC(O)-lower alkyl, adamantly or -(CH₂)_n-O-lower alkyl; n is O, 1, 2 or 3; and pharmaceutically acceptable acid addition salts and tautomers thereof.

The compounds of formula I may contain some asymmetric carbon atoms. Accordingly, the present invention includes all stereioisomeric forms of the compounds of formula I, including each of the individual enantiomers and mixtures thereof.

It has been found that the compounds of formula I have a good activity on the 5-HT₅A receptor. Therefore, the invention provides the use of a compound of formula I or a pharmaceutically acceptable salt thereof in the manufacture of medicaments for the treatment of depression (which term includes bipolar depression, unipolar depression, single or recurrent major depressive episodes with or without psychotic features, catatonic features, melancholic features, atypical features or postpartum onset, seasonal affective disorders and dysthymia, depressive disorders resulting from a general medical condition including, but not limited to, myocardial infarction, diabetes, miscarriage or abortion), anxiety disorders, (which includes generalized anxiety and social anxiety disorder, schizophrenia, panic disorders, agoraphobia, social phobia, obsessive compulsive disorders, post-traumatic stress disorders, pain (particularly neuropathic pain), memory disorders (including dementia, amnesic disorders and age- associated memory impairment), disorders of eating behaviors (including nervosa and bulimia nervosa), sexual dysfunction, sleep disorders (including disturbances of circadian rhythm, dyssomnia, insomnia, sleep apnea and narcolepsy), withdrawal from abuse of drugs (such as of cocaine, ethanol, nicotine, benzodiazepines, alcohol, caffeine, phencyclidine and phencyclidine-like compounds, opiates such as cannabis, heroin, morphine, sedative hypnotic, amphetamine or amphetamine- related drugs), motor disorders such as Parkinson's disease, dementia in Parkinson's disease, neurolep tic- induced Parkinsonism and tardive dyskinesias, as well as other psychiatric disorders and gastrointestinal disorders such as irritable bowel syndrome (WO 2004/096771).

The neurotransmitter 5-hydroxytryptamine (5-HT, serotonin) modulates a wide range of physiological and pathological processes in the central nervous system and periphery, including anxiety, sleep regulation, aggression, feeding and depression (Hoyer et al, Pharmacol. Rev. 46, 157-204, 1994). Both pharmacological characterization and molecular cloning of several 5-HT receptor genes has revealed that 5-HT mediates its diverse physiological actions through a multiplicity of receptor subtypes. These receptors belong to at least two different protein superfamilies: ligand-gated ion channel receptor (5-HT₃) and the G-protein-coupled 7-transmembrane receptors (thirteen distinct receptors cloned to date). In addition, within the G-protein-coupled receptors, serotonin exerts its actions through a multiplicity of signal transduction mechanisms.

The cloning and characterization of the human 5-HT₅A serotonin receptor has been described in FEBS Letters, 355, 242-246 (1994). The sequence is not closely related to that of any previously known serotonin receptor, with the best homology being 35% to the human 5-HT_1B receptor. It encodes a predicted 357 amino-acid protein, with seven putative transmembrane domains, consistent with that of a G-protein coupled receptor. The sequence is characterized by containing an intron between transmembrane domains V and VI. More recently coupling to Gi/o α mechanisms has been demonstrated with the inhibition of forskolin stimulated cAMP and also evidence for more complicated G- protein mediated coupling mechanisms have been proposed (Francken et al. Eur. J. Pharmacol. 361, 299-309, 1998; Noda et al., J. Neurochem. 84, 222-232, 2003) .

Furthermore, in WO 2004/096771 it is described the use of compounds, which are active on the 5-HT_5A serotonin receptor for the treatment of depression, anxiety disorders, schizophrenia, panic disorders, agoraphobia, social phobia, obsessive compulsive disorders, post-traumatic stress disorders, pain, memory disorders, dementia, disorders of eating behaviors, sexual dysfunction, sleep disorders, withdrawal from abuse of drugs, motor disorders such as Parkinson's disease, psychiatric disorders or gastrointestinal disorders. The Journal of Psychiatric Research, 38, 371-376 (2004) describes evidence for a potential significant role of the 5-HT_5A gene in schizophrenia and more specifically in patients with later age at onset.

The preferred indications with regard to the present invention are the treatment of anxiety, depression, sleep disorders and schizophrenia.

As used herein, the term "lower alkyl" denotes a saturated straight- or branched- chain group containing from 1 to 7 carbon atoms, for example, methyl, ethyl, propyl, isopropyl, n-butyl, i-butyl, 2-butyl, t-butyl and the like. Preferred alkyl groups are groups with 1 - 4 carbon atoms.

The term "cycloalkyl" denotes a saturated ring containing from 3 to 7 carbon atoms, for example cyclopropyl, cyclopentyl, cyclohexyl and the like.

The term "heterocyclyl" denotes a one or two membered cyclic group, containing at least one heteroatom, selected from the group consisting of N, O or S. Preferred groups are 2,3-dihydro-benzo[l,4]dioxin-2-yl, [l,4]dioxan-2-yl, pyridine-3-yl, piperidine-1-yl, l-pyrrolidin-2-one, 2-(lH-imidazol-4-yl, imidazolidin-2-one, and wherein the heterocyclyl group may be further substituted by lower alkyl.

The term "halogen" denotes chlorine, iodine, fluorine and bromine.

The term "lower alkyl substituted by halogen" denotes a lower alkyl group as defined above, wherein one or more hydrogen atoms may be replaced by (a) halogen atom( s) , for example CH₂F, CHF₂, CF₃, CH₂CH₂F, CH₂CHF₂ CH₂CF₃ or the like.

The term "pharmaceutically acceptable acid addition salts" embraces salts with inorganic and organic acids, such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, citric acid, formic acid, fumaric acid, maleic acid, acetic acid, succinic acid, tartaric acid, methane- sulfonic acid, p-toluenesulfonic acid and the like.

Preferred compounds of formula I are those, wherein R¹ is hydrogen and R² is methyl, for example the following compounds:

5-chloro-4-methyl-3,4-dihydro-quinazolin-2-ylamine,

(5-chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-methyl- amine,

(5-chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-cyclobutyl- amine or (5-chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(2,2-difluoro-ethyl)-amine. - A -

Preferred compounds of formula I are those, wherein R¹ is chloro and R² is methyl, for example the following compound: 5,6-dichloro-4-methyl-3,4-dihydro-quinazolin-2-ylamine, (5,6-dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-methyl- amine, (5,6-dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(2,2-difluoro-ethyl)-amine, cyclobutyl-(5,6-dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-amine, N- [ 2- ( 5 ,6- dichlor o -4- methyl- 3 ,4- dihydr o - quin azo lin - 2- ylamin o ) - ethyl] - acetamide, (5,6-dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-pentyl- amine, (5,6-dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(3-methoxy-propyl)-amine, (5,6-dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-[ 1,4] dioxan-2-ylmethyl- amine or 5,8-dichloro-4-methyl-3,4-dihydro-quinazolin-2-ylamine.

The present compounds of formula I and their pharmaceutically acceptable salts can be prepared by methods known in the art, for example by a process described below, which process comprises reacting a compound of formula

with an amine of formula

R³NH₂ III

to a compound of formula

wherein R¹, R² and R³ are as described above and R⁴ is lower alkyl,

and

if desired, converting the compounds obtained into pharmaceutically acceptable acid addition salts. In examples 1 - 43 and in the following scheme 1 the preparation of compounds of formula I is described in more detail. The starting materials are known compounds or may be prepared according to methods known in the art.

Compounds of formula I maybe prepared in accordance with the following scheme 1:

Scheme 1

R -M

R⁴-X

The substituents are as described above, R is lower alkyl and X is halogen.

An l-(2-amino-6-chloro-phenyl)-alkanone VII is reacted with a hydride transfer reagent ("H "), such as sodium borohydride, in a suitable solvent, such as ethanol, to give an intermediate which can be transformed by HSCN (which maybe generated in situ from thiocyanate salt, e.g. KSCN, and an acid, e.g. HCl) to the cyclic thiourea VIII. VIII is reacted with the alkylating agent R⁴- X, such as methyl iodide, in a suitable solvent, such as acetone, to give an 2-alkylsulfanyl-3,4-dihydro-quinazoline II, which can usually be isolated as a hydroiodide salt from the reaction mixture by filtration. II is then heated with the amine R³-NH₂ in a suitable solvent, such as acetonitril, in a microwave oven. 5-Chloro-4-alkyl-3,4-dihydro-quinazolin-2-ylamine I can then be isolated from the reaction mixture by conventional purification. l-(2-amino-6-chloro-phenyl)-alkanones VII can be prepared in several ways. In one method, a substituted 2-amino-6-chloro-benzoic acid is suitably activated, for instance with a coupling reagent such as HBTU, and converted with N,O-dimethylhydroxylamine in a suitable solvent, such as DMF, and optionally in the presence of a base, such as N- methylmorpholine, to a Weinreb amide of formula V. After isolation and purification by conventional means, V is then converted with a metalloorganic reagent R²-M, such as alkyllithium, in a suitable solvent, such as THF, for instance by allowing the reaction mixture to warm from low temperature, e.g. -78 ⁰C, to room temperature. Conventional workup and purification then gives a l-(2-amino-6-chloro-phenyl)-alkanone VII. In another method, l-(2-amino-6-chloro-phenyl)-alkanone VII are prepared by the reaction of a (substituted) 2-amino-6-chlorobenzonitrile IV with a metalloorganic reagent R²-M, such as alkylmagnesium bromide, in a suitable solvent, such as diethyl ether, and subsequent hydrolysis under acidic conditions, for instance by addition of HCl. The following abbreviations have been used:

HBTU = O-Benzotriazol-l-yl-N,N,N',N'-tetramethyluronium hexafluorophosphate DMF = N,N-dimethyrformamide THF = tetrahydrofuran M = metalloorganic group

As mentioned earlier, the compounds of formula I and their pharmaceutically usable addition salts possess valuable pharmaceutical properties. It has been found that the compounds of the present invention are active on the 5-HT_5A receptor and therefore suitable for the treatment of depression, anxiety disorders, schizophrenia, panic disorders, agoraphobia, social phobia, obsessive compulsive disorders, post-traumatic stress disorders, pain, memory disorders, dementia, disorders of eating behaviors, sexual dysfunction, sleep disorders, withdrawal from abuse of drugs, motor disorders such as Parkinson's disease, psychiatric disorders or gastrointestinal disorders.

Test description

A [³H]LSD radioligand binding assay was used to determine the affinity of the compounds for the recombinant human 5-HT₅A receptor, in membranes from transiently (cDNA) expressed 5-HT_5A receptors in Human Embryonic Kidney- EBNA (HEK-EBNA) cells. Assay buffer consisted of Tris (50 mM) buffer containing 1 mM EGTA, 10 mM MgCl₂ (pH 7.4) and 10 μM pargyline. The binding assay was carried out in 96- well-plates in the presence of [³H]LSD (approximately 1 nM), approximately 2 μg/well of membrane protein, and 0.5 mg of Ysi-poly-1- lysine SPAbeads in a final volume of 200 μl of buffer. Non-specific binding was defined using methiothepin 2μM. Compounds were tested at 10 concentrations. All assays were conducted in duplicate and repeated at least two times. Assay plates were incubated for 120 min at room temperature before centrifugation. Bound ligand was determined using a Packard Topcount scintillation counter. IC₅O values were calculated using a non-linear curve fitting program and Ki values calculated using the Cheng- Prussoff equation.

The activity of the present preferred compounds (Ki < 0.02 μM) is described in the table below:

The compounds of formula I and the pharmaceutically acceptable salts of the compounds of formula I can be used as medicaments, e.g. in the form of pharmaceutical preparations. The pharmaceutical preparations can be administered orally, e.g. in the form of tablets, coated tablets, dragees, hard and soft gelatine capsules, solutions, emulsions or suspensions. The administration can, however, also be effected rectally, e.g. in the form of suppositories, parenterally, e.g. in the form of injection solutions.

The compounds of formula I can be processed with pharmaceutically inert, inorganic or organic carriers for the production of pharmaceutical preparations.

Lactose,corn starch or derivatives thereof, talc, stearic acids or its salts and the like can be used, for example, as such carriers for tablets, coated tablets, dragees and hard gelatine capsules. Suitable carriers for soft gelatine capsules are, for example, vegetable oils, waxes, fats, semi- solid and liquid polyols and the like. Depending on the nature of the active substance no carriers are however usually required in the case of soft gelatine capsules. Suitable carriers for the production of solutions and syrups are, for example, water, polyols, glycerol, vegetable oil and the like. Suitable carriers for suppositories are, for example, natural or hardened oils, waxes, fats, semi- liquid or liquid polyols and the like.

The pharmaceutical preparations can, moreover, contain preservatives, solubilizers, stabilizers, wetting agents, emulsifiers, sweeteners, colorants, flavorants, salts for varying the osmotic pressure, buffers, masking agents or antioxidants. They can also contain still other therapeutically valuable substances.

Medicaments containing a compound of formula I or a pharmaceutically acceptable salt thereof and a therapeutically inert carrier are also an object of the present invention, as is a process for their production, which comprises bringing one or more compounds of formula I and/or pharmaceutically acceptable acid addition salts and, if desired, one or more other therapeutically valuable substances into a galenical administration form together with one or more therapeutically inert carriers.

The most preferred indications in accordance with the present invention are those, which include disorders of the central nervous system, for example the treatment of anxiety, depression, sleep disorders and schizophrenia.

The dosage can vary within wide limits and will, of course, have to be adjusted to the individual requirements in each particular case. In the case of oral administration the dosage for adults can vary from about 0.01 mg to about 1000 mg per day of a compound of general formula I or of the corresponding amount of a pharmaceutically acceptable salt thereof. The daily dosage may be administered as single dose or in divided doses and, in addition, the upper limit can also be exceeded when this is found to be indicated.

Tablet Formulation (Wet Granulation)

Item Ingredients mg/tablet

5 mg 25 mg 100 mg 500

1. Compound of formula I 5 25 100 500

2. Lactose Anhydrous DTG 125 105 30 150

3. Sta-Rx 1500 6 6 6 30

4. Microcrystalline Cellulose 30 30 30 150

5. Magnesium Stearate 1 1 1 1

Total 167 167 167 831 Manufacturing Procedure

1. Mix items 1, 2, 3 and 4 and granulate with purified water.

2. Dry the granules at 5O⁰C.

3. Pass the granules through suitable milling equipment. 4. Add item 5 and mix for three minutes; compress on a suitable press.

Capsule Formulation

Item Ingredients mg/capsule

5 mg 25 mg 100 mg 500

1. Compound of formula I 5 25 100 500

2. Hydrous Lactose 159 123 148 ---

3. Corn Starch 25 35 40 70

4. Talc 10 15 10 25

5. Magnesium Stearate 1 2 2 5

Total 200 200 300 600

Manufacturing Procedure

1. Mix items 1, 2 and 3 in a suitable mixer for 30 minutes.

2. Add items 4 and 5 and mix for 3 minutes. 3. Fill into a suitable capsule.

Compounds of formula I maybe prepared as shown in the following description:

Example 1 5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-ylamine

a) l-(2-Amino-6-chloro-phenyl)-ethanone

A suspension of 2-amino-6-chlorobenzonitrile (3.67 g, 24 mmol) in diethyl ether (60 ml) was added slowly to methylmagnesium bromide (56 ml, 3 M in Et₂O, 170 mmol), and the mixture was heated to reflux, until all starting material was consumed (3h, HPLC control). The mixture was then placed in an ice bad, and HCl (6M, 58 ml) was slowly added (vigorous reaction). The mixture was then again heated to reflux, cooled and made alkaline by addition of solid Na₂CO₃. The mixture was extracted several times with ethyl acetate, the combined organic phases were dried (Na₂SO₄), and the solvent was evaporated under reduced pressure. Purification of the residue by column chromatography (silica gel, solvent gradient n-heptan / ethyl acetate = 100 / 0 - 60 / 40) gave the title compound

(2.72g, 67 %). ¹H NMR (CDCl₃): δ 2.65 (3H, s), 4.91 (2H, bs), 6.58 (IH, d), 6.73 (IH, d), 7.07 (IH, t).

b) 5-Chloro-4-methyl-3,4-dihvdro- lH-quinazoh^'ne-2-thione

At a temperature of 65 ⁰C, sodium borohydride was added to a solution of l-(2-amino-6- chloro-phenyl)-ethanone in ethanol, and the mixture was heated overnight (65 ⁰C). Water, KSCN and HCl were then added subsequently, and the mixture was again heated (3 h, 65 ⁰C). The majority of the title compound precipitated upon cooling and could be isolated in sufficiently pure form by filtration. A small additional amount of the desired product was obtained by workup of the mother liquor (evaporation of solvent, column chromatography [silica gel, solvent gradient n-heptan / ethyl acetate = 100 / 0 - 60 / 40]). The title compound was obtained in a combined yield of 1.46 g (43 %).

¹H NMR (d⁶-DMSO): δ 1.26 (3H, d), 4.58 (IH, q), 6.97 (IH, d), 7.09 (IH, d), 7.23 (IH, t), 8.99 (IH, bs), 10.73 (IH, bs).

c) 5-Chloro-4-methyl-2-methylsulfanyl-3,4-dihvdro-quinazoline hydroiodide Methyl iodide (1.16 ml, 19 mmol) was added to a suspension of 5-chloro-4-methyl-3,4- dihydro-lH-quinazoline-2-thione (1.32 g, 6.2 mmol) in aceton (15 ml) and the mixture was stirred at r.t. over the weekend (the reaction is usually complete after 12 h). The precipitated product (2.08 g, 87 %) was sufficiently pure for the next step. ¹H NMR (d⁶-DMSO): δ 1.42 (3H, d), 2.76 (3H, s), 4.97 (IH, q), 7.11-7.14 (IH, m), 7.39-7.43 (2H, m), 10.58 (IH, bs), 12.38 (IH, bs).

d) 5-Chloro-4-methyl-3,4-dihvdro-quinazolin-2-ylamine

5-Chloro-4-methyl-2-methylsulfanyl-3,4-dihydro-quinazoline hydroiodide (100 mg, 0.28 mmol) was suspended in a mixture of ammonium hydroxide (1 ml , 25 % in H₂O) and acetonitrile (ImI), and heated in a microwave oven to 13O⁰C (15min) and subsequently to 17O⁰C (30min). The title compound (35 mg, 62 %) was isolated from the reaction mixture by preparative, reverse-phase HPLC (YMC CombiPrep C18 column 50x20mm, solvent gradient 5-95 % CH₃CN in 0.1 % TFA(aq) over 6.0 min, λ = 230 nm, flow rate 40 ml/min) as a white solid. ¹H NMR (CDCl₃): δ 1.35 (3H, d), 4.83 (IH, q), 6.85 (IH, d), 6.92 (IH, d), 7.06 (3H, t).

Example 2 (5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-methyl-amine

The title compound (MS: m/e = 209.9 [M+H⁺]) was prepared in analogy to example 1 from methylamine.

Example 3

(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-cyclobutyl-amine

The title compound (MS: m/e = 250.1 [M+H⁺]) was prepared in analogy to example 1 from cyclobutylamine.

Example 4 (5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(2,2,2-trifluoro-ethyl)-amine

The title compound (MS: m/e = 278.3 [M+H⁺]) was prepared in analogy to example 1 from 2,2,2-trifluoroethylamine.

Example 5

(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(2,2-difluoro-ethyl)-amine

The title compound (MS: m/e = 260.3 [M+H⁺]) was prepared in analogy to example 1 from 2,2-difluoroethylamine.

Example 6

N'-(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-N,N-diisopropyl-ethane-l,2- diamine

The title compound (MS: m/e = 323.1 [M+H⁺]) was prepared in analogy to example 1 from N,N-diisopropyl-ethane-l,2-diamine.

Example 7

(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(2,3-dihydro-benzo[l,4]dioxin-2- ylmethyl) - amin e

The title compound (MS: m/e = 344.0 [M+H⁺]) was prepared in analogy to example 1 from 2,3-dihydro-benzo[ 1,4] dioxin-2-ylmethyl-amine.

Example 8 5,6-Dichloro-4-methyl-3,4-dihydro-quinazolin-2-ylamine

The title compound (MS: m/e = 230.1 [M+H⁺]) was prepared in analogy to example 1 from 2-amino-5,6-dichlorobenzonitrile. 2-Amino-5,6-dichlorobenzonitrile can be prepared by the method of Trinka, P.; Slegel, P.; Reiter, J. J. Prakt. Chem. 1996, 338(1), 675-678. Example 9 (5,6-Dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-methyl-amine

RThe title compound (MS: m/e = 244.1 [M+H⁺]) was prepared in analogy to example 1 from 2-amino-5,6-dichlorobenzonitrile and methylamine.

Example 10 (5,6-Dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(2,2-difluoro-ethyl)-amine

The title compound (MS: m/e = 293.9 [M+H⁺]) was prepared in analogy to example 1 from 2-amino-5,6-dichlorobenzonitrile and 2,2-difluoroethylamine.

Example 11 5-Chloro-4-ethyl-3,4-dihydro-quinazolin-2-ylamine

The title compound (MS: m/e = 210.1 [M+H⁺]) was prepared in analogy to example 1 from ethylmagnesium bromide.

Example 12 5,6-Dichloro-4-ethyl-3,4-dihydro-quinazolin-2-ylamine

The title compound (MS: m/e = 244.1 [M+H⁺]) was prepared in analogy to example 1 from 2-amino-5,6-dichlorobenzonitrile and ethylmagnesium bromide.

Example 13

(5,6-Dichloro-4-ethyl-3,4-dihydro-quinazolin-2-yl)-methyl-amine

The title compound (MS: m/e = 258.0 [M+H⁺]) was prepared in analogy to example 1 from 2-amino-5,6-dichlorobenzonitrile, ethylmagnesium bromide, and methylamine.

Example 14

(5,6-Dichloro-4-ethyl-3,4-dihydro-quinazolin-2-yl)-(2,2-difluoro-ethyl)-amine

The title compound (MS: m/e = 308.1 [M+H⁺]) was prepared in analogy to example 1 from 2-amino-5,6-dichlorobenzonitrile, ethylmagnesium bromide, and 2,2- difluoroethylamine.

Example 15 Cyclobutyl-(5,6-dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-amine

The title compound was prepared in analogy to example 1 from 2-amino-5,6- dichlorobenzonitrile and cyclobutylamine.

¹H NMR (CDCl₃): δ 1.08 (3H, d), 1.52-1.58 (2H, m), 1.73-1.77 (2H, d), 2.11-2.17 (2H, d), 4.17 (IH, tt), 4.55 (IH, q), 6.27 (IH, bs), 6.37 (IH, bs), 6.57 (IH, d), 7.13 (IH, d).

Example 16

N-[2-(5,6-Dichloro-4-methyl-3,4-dihydro-quinazolin-2-ylamino)-ethyl]-acetamide

The title compound (MS: m/e = 316.9 [M+H⁺]) was prepared in analogy to example 1 from 2-amino-5,6-dichlorobenzonitrile and N- (2- amino- ethyl) -acetamide. Example 17 Adamantan-l-ylmethyl-(5,6-dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-amine

The title compound (MS: m/e = 378.3 [M+H⁺]) was prepared in analogy to example 1 from 2-amino-5,6-dichlorobenzonitrile and adamantan-1-yl-methylamine.

Example 18 (5,6-Dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-pentyl-amine

The title compound (MS: m/e = 300.3 [M+H⁺]) was prepared in analogy to example 1 from 2-amino-5,6-dichlorobenzonitrile and pentylamine.

Example 19 (5,6-Dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(3-methoxy-propyl)-amine

The title compound (MS: m/e = 303.2 [M+H⁺]) was prepared in analogy to example 1 from 2-amino-5,6-dichlorobenzonitrile and 3-methoxy-propylamine.

Example 20 N'-(5,6-Dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-N,N-diisopropyl-ethane-l,2- diamine

The title compound (MS: m/e = 357.3 [M+H⁺]) was prepared in analogy to example 1 from 2-amino-5,6-dichlorobenzonitrile and N, N-diisopropyl-ethane-l,2-diamine. Example 21

(5,6-Dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-[l,4]dioxan-2-ylmethyl-amine

The title compound (MS: m/e = 330.2 [M+H⁺]) was prepared in analogy to example 1 from 2-amino-5,6-dichlorobenzonitrile and [l,4]dioxan-2-yl-methylamine.

Example 22

(5,6-Dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(2,3-dihydro-benzo[l,4]dioxin-2- ylmethyl) - amin e

The title compound (MS: m/e = 378.1 [M+H⁺]) was prepared in analogy to example 1 from 2-amino-5,6-dichlorobenzonitrile and 2,3-dihydrobenzo[l,4]dioxin-2- ylmethylamine.

Example 23 5,8-Dichloro-4-methyl-3,4-dihydro-quinazolin-2-ylamine

a) 2-Amino-3,6-dichloro-N-methoxy-N-methyl-benzamide N,O-dimethlyhydroxylamine hydrochloride (3.28 g, 33 mmol) and 2-amino-3,6- dichlorobenzoic acid (4.76 g, 22 mmol) were dissolved in DMF (110 ml). At r.t. under nitrogen and stirring first N-methyl morpholine (10 g, 99 mmol) and then HBTU

(12.5 g, 33 mmol) were added and the reaction was stirred at r.t. overnight. The reaction was poured onto water and extracted twice with ethyl acetate. The organic layer was dried over sodium sulfate, filtered and the solvent was evaporated. The residue was treated with heptane and little diethyl ether to yield 4 g of the product. The mother liquor was purified by column chromatography (silica gel, solvent gradient n-heptan / ethyl acetate = 3 / 7) to give another batch of the title compound as an off- white solid (5.52 g, 100 %). ¹H NMR (d⁶-DMSO): δ 3.29 (3H, s), 3.50 (3H, s), 5.43 (2H, bs), 6.69 (IH, d), 7.26 (IH, d).

b) l-(2-Amino-3,6-dichloro-phenyl)-ethanone At -78 ⁰C a solution of methyl lithium (1.6M in diethyl ether, 25 ml, 40 mmol) was added dropwise to a solution of 2-amino-3,6-dichloro-N-methoxy-N-methyl-benzamide (2.5 g, 10 mmol) in tetrahydrofurane (100 ml). After complete addition the reaction was warmed to r.t. The dark solution was stirred for 3 hours at room temperature. Under ice cooling 2N aqueous hydrochloride solution (25 ml) was added dropwise and stirred at r.t. for 30 minutes. The reaction was diluted with water, extracted twice with ethyl acetate. The combined organic layers were washed with saturated aqueous sodium chloride solution, dried over sodium sulfate, filtered and the solvent was evaporated. The residue was purified by column chromatography (silica gel, solvent gradient n-heptan / ethyl acetate = 3 / 7) to yield the title compound as an orange oil (0.59 g, 29 %). ¹H NMR (CDCl₃): δ 2.65 (3H, s), 5.32 (2H, bs), 6.69 (IH, d), 7.21 (IH, d).

c) 5,8-Dichloro-4-methyl-3,4-dihvdro- lH-quinazoline-2-thione

At a temperature of 65 ⁰C, sodium borohydride (0.13 g, 3.4 mmol) was added to a solution of l-(2-amino-3,6-dichloro-phenyl)-ethanone (1.16 g, 5.7 mmol) in ethanol (12 ml), and the mixture was heated overnight (65 ⁰C). Water (14.4 ml), KSCN (0.61 g, 6.3 mmol) and concentrated aqueous hydrogen chloride solution (3.6 ml) were then added subsequently, and the mixture was again heated (3 h, 65 ⁰C). The majority of the title compound precipitated upon cooling and could be isolated in pure form by filtration and washing with water and ethanol to yield a light yellow solid (0.96 g, 69 %).

¹H NMR (CDCl₃): δ 1.56 (3H, d), 4.85 (IH, mq), 7.02 (IH, bs), 7.05 (IH, d), 7.25 (IH, d), 8.22 (lH, bs).

MS (EI): m/e = 245.8/248.0 [M⁺]

d) 5,8-Dichloro-4-methyl-2-methylsulfanyl-3,4-dihvdro-quinazoline hydro iodide

Methyl iodide (0.73 ml, 11.7 mmol) was added to a suspension of 5,8-dichloro-4-methyl- 3,4-dihydro-lH-quinazoline-2-thione (0.96 g, 3.9 mmol) in aceton (12 ml) and the mixture was stirred at room temperature overnight. The reaction was diluted with diethyl ether and the precipitated product (1.31 g, 86 %) was isolated by filtration as a white solid. ¹H NMR (d⁶-DMSO): δ 1.29 (3H, d), 2.63 (3H, s), 4.81 (IH, q), 7.25 (IH, d), 7.46 (IH, d).

MS: m/e = 261.0/263.0 [M+H⁺].

e) 5,8-Dichloro-4-methyl-3,4-dihvdro-quinazolin-2-ylamine

5,8-Dichloro-4-methyl-2-methylsulfanyl-3,4-dihydro-quinazoline hydroiodide (116 mg, 0.30 mmol) was suspended in a mixture of ammonium hydroxide (0.22 ml , 25 % in H₂O, 3 mmol) and acetonitrile (0.9 ml), and heated in a microwave oven to 170 ⁰C (30 min). The reaction was cooled in an ice bath and treated with IN aqueous sodium hydroxide solution (0.9 ml) and 5-6 drops of concentrated solution of aqueous hydrogene peroxide. A little water was added and the title compound (36 mg, 52 %) was filtered off as a white solid.

¹H NMR (d⁶-DMSO): δ 1.07 (3H, d), 4.54 (IH, mq), 5.96 (2H, bs), 6.57 (IH, bs), 6.67 (IH, d), 7.07 (IH, d). MS: m/e = 230.1/232.0 [M+H⁺] .

Example 24 Cyclobutyl-(5,8-dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-amine

The title compound (MS: m/e = 284.1/286.1 [M+H⁺] ) was prepared in analogy to example 23 from cyclobutyl amine.

Example 25 (5,8-Dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(2,2-difluoro-ethyl)-amine

The title compound (MS: m/e = 294.1/296.2 [M+H⁺]) was prepared in analogy to example 23 from 2,2-difluoroethyl amine.

Example 26 (5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-phenethyl-amine

The title compound (MS: m/e = 300.2 [M+H⁺]) was prepared in analogy to example 1 from phenethylamine. Example 27

(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(3-phenyl-propyl)-amine

The title compound (MS: m/e = 314.1 [M+H⁺]) was prepared in analogy to example 1 from 3-phenyl-propylamine.

Example 28

(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(2-methoxy-ethyl)-amine

The title compound (MS: m/e = 254.2 [M+H⁺]) was prepared in analogy to example 1 from 2-methoxy-ethylamine.

Example 29

(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-pyridin-3-ylmethyl-amine

The title compound (MS: m/e = 287.2 [M+H⁺]) was prepared in analogy to example 1 from C-pyridin-3-yl-methylamine. Example 30

(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-ethyl-amine

The title compound (MS: m/e = 224.2 [M+H⁺] ) was prepared in analogy to example 1 from ethylamine.

Example 31

(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-cyclopropylmethyl-amine

The title compound (MS: m/e = 250.2 [M+H⁺]) was prepared in analogy to example 1 from C-cyclopropyl-methylamine.

Example 32

N-[2-(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-ylamino)-ethyl]-acetamide

The title compound (MS: m/e = 281.2 [M+H⁺]) was prepared in analogy to example 1 from N- (2- amino- ethyl) -acetamide.

Example 33

Butyl-(5-chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-amine

The title compound (MS: m/e = 252.2 [M+H⁺]) was prepared in analogy to example 1 from butylamine. Example 34

(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-[2-(4-fluoro-phenyl)-ethyl] -amine

The title compound (MS: m/e = 318.0 [M+H⁺]) was prepared in analogy to example 1 from 2-(4-fluoro-phenyl)-ethylamine.

Example 35

(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(2-piperidin-l-yl-ethyl)-amine

The title compound (MS: m/e = 307.3 [M+H⁺]) was prepared in analogy to example 1 from 2-piperidin-l-yl-ethylamine.

Example 36

(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(3-methoxy-propyl)-amine

The title compound (MS: m/e = 268.2 [M+H⁺]) was prepared in analogy to example 1 from 3-methoxy-propylamine.

Example 37

(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-isobutyl-amine

The title compound (MS: m/e = 252.2 [M+H⁺]) was prepared in analogy to example 1 from isobutylamine.

Example 38

l-[3-(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-ylamino)-propyl]-pyrrolidin-2-one

The title compound (MS: m/e = 321.1 [M+H⁺]) was prepared in analogy to example 1 from l-(3-amino-propyl)-pyrrolidin-2-one.

Example 39

(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-[2-( IH- imidazo 1-4- yl)-ethyl] -amine

The title compound (MS: m/e = 290.1 [M+Η⁺]) was prepared in analogy to example 1 from histamine.

Example 40

l-[2-(5-Chloro-4-methyl-3,4-dihydro-quinazo lin -2- ylamino)-ethyl] -imidazo lidin-2-one

The title compound (MS: m/e = 308.2 [M+H⁺]) was prepared in analogy to example 1 from 1- (2- amino-ethyl) -imidazo lidin-2-one.

Example 41

(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-[2-(l-methyl-pyrrolidin-2-yl)-ethyl]- amine

The title compound (MS: m/e = 307.3 [M+H⁺]) was prepared in analogy to example 1 from 2-( l-Methyl-pyrrolidin-2-yl)-ethylamine.

Example 42

(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(l-ethyl-pyrrolidin-2-ylmethyl)- amine

The title compound (MS: m/e = 307.3 [M+H⁺]) was prepared in analogy to example 1 from C-( l-Ethyl-pyrrolidin-2-yl)-methylamine.

Example 43

(5-Chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-[l,4]dioxan-2-ylmethyl-amine

The title compound (MS: m/e = 296.2 [M+H⁺]) was prepared in analogy to example 1 from C-[l,4]dioxan-2-yl-methylamine.

Claims

1. Compounds of general formula

wherein R¹ is hydrogen or halogen;

R² is lower alkyl;

2. Compounds of formula I according to claim 1, wherein R¹ is hydrogen and R is methyl.

3. Compounds of formula I according to claim 2, which compounds are 5-chloro-4-methyl-3,4-dihydro-quinazolin-2-ylamine, (5-chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-methyl- amine, (5-chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-cyclobutyl- amine or

(5-chloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(2,2-difluoro-ethyl)-amine.

4. Compounds of formula I according to claim 1, wherein R¹ is chloro and R² is methyl. 5. Compounds of formula I according to claim 4, which compounds are

5,6-dichloro-4-methyl-3,4-dihydro-quinazolin-2-ylamine, (5,6-dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-methyl- amine, (5,6-dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(2,2-difluoro-ethyl)-amine, cyclobutyl-(5,6-dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-amine, N-[2-(5,6-dichloro-4-methyl-3,4-dihydro-quinazolin-2-ylamino)-ethyl]-acetamide, (5,6-dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-pentyl-amine, (5,6-dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-(3-methoxy-propyl)-amine, (5,6-dichloro-4-methyl-3,4-dihydro-quinazolin-2-yl)-[ 1,4] dioxan-2-ylmethyl- amine or 5,8-dichloro-4-methyl-3,4-dihydro-quinazolin-2-ylamine. R¹ is hydrogen and R² is lower alkyl.

6. A process for preparing a compound of formula I as defined in claim 1, which process comprises

reacting a compound of formula

with an amine of formula

R³NH₂ III

to a compound of formula

wherein R¹, R² and R³ are as described above and R⁴ is lower alkyl,

and

if desired, converting the compounds obtained into pharmaceutically acceptable acid addition salts.

7. A medicament containing one or more compounds as claimed in formula I in accordance with claim 1 and pharmaceutically acceptable excipients for the treatment of depression, anxiety disorders, schizophrenia, panic disorders, agoraphobia, social phobia, obsessive compulsive disorders, post-traumatic stress disorders, pain, memory disorders, dementia, disorders of eating behaviors, sexual dysfunction, sleep disorders, withdrawal from abuse of drugs, motor disorders such as Parkinson's disease, psychiatric disorders or gastrointestinal disorders.

8. Compounds of formula I according to claim 1 and pharmaceutically acceptable excipients for the treatment of depression, anxiety disorders, schizophrenia, panic disorders, agoraphobia, social phobia, obsessive compulsive disorders, post-traumatic stress disorders, pain, memory disorders, dementia, disorders of eating behaviors, sexual dysfunction, sleep disorders, withdrawal from abuse of drugs, motor disorders such as Parkinson's disease, psychiatric disorders or gastrointestinal disorders.

9. The use of compounds of formula I for the manufacture of medicaments for the treatment of depression, anxiety disorders, schizophrenia, panic disorders, agoraphobia, social phobia, obsessive compulsive disorders, post-traumatic stress disorders, pain, memory disorders, dementia, disorders of eating behaviors, sexual dysfunction, sleep disorders, withdrawal from abuse of drugs, motor disorders such as Parkinson's disease, psychiatric disorders or gastrointestinal disorders.

10. The invention as hereinbefore described.

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