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  • C07K5/00—Peptides containing up to four amino acids in a fully defined sequence; Derivatives thereof
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  • C07K5/08—Tripeptides
  • C07K5/0802—Tripeptides with the first amino acid being neutral
  • C07K5/0804—Tripeptides with the first amino acid being neutral and aliphatic
  • C07K5/0808—Tripeptides with the first amino acid being neutral and aliphatic the side chain containing 2 to 4 carbon atoms, e.g. Val, Ile, Leu
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  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K45/00—Medicinal preparations containing active ingredients not provided for in groups A61K31/00 - A61K41/00
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• • A—HUMAN NECESSITIES
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  • A61P25/00—Drugs for disorders of the nervous system
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• • A—HUMAN NECESSITIES
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  • A61P25/00—Drugs for disorders of the nervous system
  • A61P25/28—Drugs for disorders of the nervous system for treating neurodegenerative disorders of the central nervous system, e.g. nootropic agents, cognition enhancers, drugs for treating Alzheimer's disease or other forms of dementia
• • A—HUMAN NECESSITIES
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  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
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• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P9/00—Drugs for disorders of the cardiovascular system
  • A61P9/10—Drugs for disorders of the cardiovascular system for treating ischaemic or atherosclerotic diseases, e.g. antianginal drugs, coronary vasodilators, drugs for myocardial infarction, retinopathy, cerebrovascula insufficiency, renal arteriosclerosis
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K5/00—Peptides containing up to four amino acids in a fully defined sequence; Derivatives thereof
  • C07K5/04—Peptides containing up to four amino acids in a fully defined sequence; Derivatives thereof containing only normal peptide links
  • C07K5/08—Tripeptides
  • C07K5/0802—Tripeptides with the first amino acid being neutral
  • C07K5/0804—Tripeptides with the first amino acid being neutral and aliphatic
  • C07K5/0806—Tripeptides with the first amino acid being neutral and aliphatic the side chain containing 0 or 1 carbon atoms, i.e. Gly, Ala

Definitions

• the present invention relates to novel analogs of Glycyl-Prolyl-Glutamate (GPE) and methods of their use. Additionally, this invention relates to the use of these compounds and pharmaceutical compositions thereof in the treatment of diseases and conditions characterised by neuronal degeneration and/or death.
• GPE Glycyl-Prolyl-Glutamate
• Gly-Pro-Glu The tripeptide Glycyl-L-Prolyl-L-Glutamate (Gly-Pro-Glu or GPE) is a naturally occurring peptide, which is proteolytically cleaved from insulin-like growth factor- 1 (IGF-I).
• IGF-I insulin-like growth factor- 1
• GPE has been postulated that some of the neuroprotective actions of IGF-I are mediated by GPE although the precise mechanism of action remains unclear.
• GPE has a different mode of action to IGF-I as GPE does not bind to the IGF-I receptor.
• GPE has been shown to bind with low affinity to the N-methyl-D-aspartate ( ⁇ MDA) receptor and also elicit a biological response via other mechanisms.
• ⁇ MDA N-methyl-D-aspartate
• GPE facilitates the release of dopamine through interaction with the ⁇ MDA receptor but GPE stimulated acetylcholine release is via an unknown, non- ⁇ MDA pathway.
• GPE can act as a neuronal rescue agent following brain injury or disease, including hypoxic-ischemic brain injury, ⁇ MDA challenge, chemical toxins and in animal models of Parkinson's and Alzheimer's disease. Analogs of GPE are thus of interest in the development of novel pharmaceutical agents for the treatment of central nervous system (C ⁇ S) injuries and neurodegenerative disorders among others.
• C ⁇ S central nervous system
• GPE analogs and compositions for treatment of disorders of the nervous system, including disorders involving neurodegeneration and neural cell death, as well as agents for treating other types of disorders.
• this invention provides novel GPE analogs.
• the proline residue is modified.
• Some embodiments of the invention provide molecules having the structural formula and substituents described below:
• Certain embodiments of this invention include compounds of Formula 1 or a pharmaceutically acceptable salt or hydrate thereof, wherein: the bond between X 1 and X 2 may be saturated or unsaturated;
• X 1 is selected from the group consisting of CH 2 , S, C(OH)H and in the case where the bond between X 1 and X 2 is unsaturated, CH;
• X 2 is selected from the group consisting of CH 2 , CH 2 CH 2 and in the case where the bond between
• X 1 and X 2 is unsaturated, CH;
• R 1 is selected from the group consisting of H, alkyl, alkenyl, aryl, arylalkyl, substituted alkyl, substituted alkenyl, substituted aryl or substituted arylalkyl;
• R 2 is CH 3 or COOH
• R 3 is selected from the group consisting of H, alkyl or NR 3 R 3 taken together is pyrrolidino or piperidino;
• R * is selected from the group consisting of H, alkyl, alkenyl, aryl, arylalkyl, substituted alkyl, substituted alkenyl, substituted aryl or substituted arylalkyl;
• R 5 is selected from the group consisting of H, alkyl, alkenyl, aryl, arylalkyl, substituted alkyl, substituted alkenyl, substituted aryl or substituted arylalkyl; n is an integer from 0 to 2.
• Additional embodiments include compounds of Formula 3 or a pharmaceutically acceptable salt or hydrate thereof, wherein or a pharmaceutically acceptable salt or hydrate thereof, wherein:
• R 1 is selected from the group consisting of H, alkyl, alkenyl, aryl, arylalkyl, substituted alkyl, substituted alkenyl, substituted aryl or substituted arylalkyl;
• R 2 is CH 3 or COOH
• R 3 is selected from the group consisting of H, alkyl or NR 3 R 3 taken together is pyrrolidino or piperidino;
• R 4 is selected from the group consisting of H, alkyl, alkenyl, aryl, arylalkyl, substituted alkyl, substituted alkenyl, substituted aryl or substituted arylalkyl; n is an integer from O to 2.
• FIG. 4 Further embodiments include a compound of Formula 4 or a pharmaceutically acceptable salt or hydrate thereof, wherein R 1 is selected from the group consisting of H, alkyl, alkenyl, aryl, arylalkyl, substituted alkyl, substituted alkenyl, substituted aryl or substituted arylalkyl.
• this invention provides pharmaceutical compositions comprising a pharmaceutically acceptable excipient and a therapeutically effective amount of at least one compound of this invention. These compositions find use as anti-apoptotic and anti-necrotic agents and for other conditions involving neural degeneration or injury.
• this invention provides a method of treating an animal having a disease or injury capable of treatment by administration of a suitable compound, comprising administration to that animal of at least one compound of this invention, optionally in conjunction with at least one other conventional therapeutic agent for the disease being treated.
• the animal to be treated is a human.
• this invention provides methods of preparing the compounds of Formulas 1-4 of this invention.
• this invention provides methods of synthesising, formulating and preparing pharmaceutical preparations comprising compounds of Formulas 1-4 of this invention.
• Figure 1 is a graph showing effects of analog 49 (Glycyl-L-thia-5,5-dimethylprolyl-L- glutamic acid) on neuronal survival following administration of apoptosis-inducing toxin (10OnM okadaic acid) on cortical cell culture.
• analog 49 Glycyl-L-thia-5,5-dimethylprolyl-L- glutamic acid
• Figure 2 is a graph showing effects of analog 50 (Glycyl-(D,L)-5,5-dimethylprolyl-L- glutamic acid) on neuronal survival following excitotoxic oxidative stress in cortical cell culture induced by 100//M H 2 O 2 .
• analog 50 Glycyl-(D,L)-5,5-dimethylprolyl-L- glutamic acid
• Figure 3 is a graph showing effects of analog 60 (Glycyl-trans-4-hydroxy-L-prolyl-L- glutamic acid) on neuronal survival following administration of apoptosis-inducing toxin (3OnM okadaic acid) in striatal cell culture.
• analog 60 Glycyl-trans-4-hydroxy-L-prolyl-L- glutamic acid
• Figure 4 is a graph showing effects of analog 64 (Aminoisobutryl-L-prolyl-L-glutamic acid) on neuronal survival following administration of apoptosis-inducing toxin (3OnM okadaic acid) in striatal cell culture.
• analog 64 Aminoisobutryl-L-prolyl-L-glutamic acid
• Figure 5 is a graph showing effects of analog 65 (Glycyl-L-prolyl-L-Norvaline) on neuronal survival following administration of apoptosis-inducing toxin (10OnM okadaic acid) in cortical cell culture.
• Figure 6 is a graph showing effects of analog 66 (Glycyl-D,L-pipecolinyl-L-glutamic acid) on neuronal survival following administration of apoptosis-inducing toxin (okadaic acid) in striatal cell culture.
• Figure 7 is a graph showing effects of analog 67 (Pyrrolidinoglycyl-L-2-Methyl-proline-L- Glutamic Acid) on neuronal survival following excitotoxic/oxidative stress (induced by 0.5mM 3- NP glutamate) in cerebellar cell culture.
• analog 67 Pyrrolidinoglycyl-L-2-Methyl-proline-L- Glutamic Acid
• alkenyl refers to an unsaturated branched, straight chain or cyclic hydrocarbon radical having at least one carbon-carbon double bond.
• the radical can be in either the cis or tram conformation about the double bond(s).
• Exemplary alkenyl groups include allyl, ethenyl, propenyl, isopropenyl, butenyl, isobutenyl, cyclopentenyl and the like. In some embodiments the alkenyl groups are (C 2 -C 5 ) alkenyl and in other embodiments allyl can be particularly useful.
• Alkyl refers to a saturated branched, straight chain or cyclic hydrocarbon radical.
• alkyl groups include methyl, ethyl, isopropyl, cyclopropyl, tert-buty ⁇ , cyclopropylmethyl, hexyl and the like. In some embodiments the alkyl groups are (C]-C 6 ) alkyl.
• Alkynyl refers to an unsaturated branched, straight chain or cyclic hydrocarbon radical having at least one carbon-carbon triple bond.
• exemplary alkynyl groups include ethynyl, propynyl, butynyl, isobutynyl and the like.
• the alkynyl group is (C 2 -C 6 ) alkynyl.
• Aryl refers to an unsaturated cyclic hydrocarbon radical with a conjugated T ⁇ electron system.
• exemplary aryl groups include phenyl, naphthyl and the like. In some embodiments the aryl group is (C 5 -C 2 o) aryl.
• Arylalkyl refers to a straight chain alkyl, alkenyl or alkynyl group wherein one of the hydrogen atoms bonded to the terminal carbon is replaced with an aryl group.
• exemplary arylalkyl groups include benzyl, naphthylmethyl, benzylidene and the like.
• Glycyl-Prolyl-Glutamate or "Gly-Pro-Glu” or “GPE” refers to a tripeptide containing the named amino acids. It should be understood that the above named compounds also include the C-terminal acid form of the peptide, also called “Glycyl-Prolyl-Glutamic Acid.”
• a “growth factor” refers to an extracellular polypeptide-signalling molecule that stimulates a cell to grow or proliferate.
• Heteroalkyl refers to an alkyl moiety wherein one or more carbon atoms are replaced with another atom such as N, P, O, S etc.
• exemplary heteroalkyl groups include pyrrolidine, morpholine, piperidine, piperazine, imidazolidine, pyrazolidine, terahydrofuran, (C 1 -Ci 0 ) substituted amines, (C 2 -C 6 ) thioethers and the like.
• Heteroaryl refers to an aryl moiety wherein one or more carbon atoms are replaced with another atom such as N, P, O, S etc.
• exemplary heteroaryl groups include carbazole, furan, imidazole, indazole, indole, isoquinoline, purine, pyrazine, pyrazole, pyridazine, pyridine, pyrrole, thiazole, thiophene, triazole and the like.
• “Injury” includes any acute or chronic damage of an animal that results in degeneration or death of cells in the nervous system. Such cells include neuronal cells and non-neuronal cells.
• Injury includes stroke, non-hemorrhagic stroke, traumatic brain injury, perinatal asphyxia associated with fetal distress such as following abruption, cord occlusion or associated with intrauterine growth retardation, perinatal asphyxia associated with failure of adequate resuscitation or respiration, severe CNS insults associated with near miss drowning, near miss cot death, carbon monoxide inhalation, ammonia or other gaseous intoxication, cardiac arrest, coma, meningitis, hypoglycemia and status epiiepticus, episodes of cerebral asphyxia associated with coronary bypass surgery, hypotensive episodes and hypertensive crises, and cerebral trauma. It is to be undestood that the above examples are by way of illustration only, and are not intended to be a complete listing of injuries capable of being treated by the compounds and methods of this invention
• a “pharmaceutically acceptable excipient” refers to an excipient that is useful in preparing a pharmaceutical composition that is generally safe, non-toxic, and desirable, and includes excipients that are acceptable for veterinary use as well as for human pharmaceutical use. Such excipients can be solid, liquid, semisolid, or, in the case of an aerosol composition, gaseous.
• a “pharmaceutically acceptable salt” refers to a salt that is pharmaceutically acceptable and has the desired pharmacological properties. Such salts include salts that can be formed where acidic protons present in the compounds are capable of reacting with inorganic or organic bases. Suitable inorganic salts include those formed with the alkali metals, e.g. sodium and potassium, magnesium, calcium, and aluminium.
• Suitable organic salts include those formed with organic bases such as the amine bases e.g. ethanolamine, diethanolamine, triethanolamine, tromethamine, N-methylglucamine, and the like. Such salts also include acid addition salts formed with inorganic acids (e.g. hydrochloric and hydrobromic acids) and organic acids (e.g. acetic acid, citric acid, maleic acid, and the alkane- and arene-sulfonic acids such as methanesulfonic acid and benzenesulfonic acid). When there are two acidic groups present, a pharmaceutically acceptable salt can be a mono-acid mono-salt or a di-salt; and similarly where there are more than two acidic groups present, some or all of such groups can be salified.
• organic bases such as the amine bases e.g. ethanolamine, diethanolamine, triethanolamine, tromethamine, N-methylglucamine, and the like.
• Such salts also include acid addition salts formed
• a "protecting group” has the meaning conventionally associated with it in organic synthesis, i.e. a group that selectively blocks one or more reactive sites in a multifunctional compound such that a chemical reaction can be carried out selectively on another unprotected reactive site and such that the group can readily be removed after the selective reaction is complete.
• Substituted refers to where one or more of the hydrogen atoms on an alkyl, heteroalkyl, alkenyl, alkynyl, aryl, heteroaryl or arylalkyl radical are independently replaced with another substituent.
• substituents include -R', -OR 1 , -SR 1 , -NR 1 R 1 , -NO 2 , -CN, -C(O)R 1 , - C(O)OR 1 , -C(O)NR 1 R', -C(NR')NR'R', -NR-C(NR)-OR', -NR'-C(NR')-SR', NR'-C(NR')-NR'R', trihalomethyl and halogen where each R' is independently -H, alkyl, heteroalkyl, alkenyl, alkynyl, aryl, arylalkyl, heteroaryl or heteroarylalkyl.
• a “therapeutically effective amount” means the amount that, when administered to an animal for treating a disease, is sufficient to effect treatment for that disease; that is, an amount that decreases adverse symptoms or findings, promotes desirable symptoms or findings, and/or treats an underlying disorder, and/or is curative.
• Treating" or “treatment” of a disease includes preventing the disease from occurring in an animal that may be predisposed to the disease but does not yet experience or exhibit symptoms of the disease (prophylactic treatment), inhibiting the disease (slowing or arresting its development), providing relief from the symptoms or side-effects of the disease (including palliative treatment), and relieving the disease (causing regression of the disease).
• Implicit hydrogen atoms (such as the hydrogens on the pyrrole ring, etc.) are omitted from the formulae for clarity, but should be understood to be present.
• One aspect of the invention includes molecules having the structural formulae and substituents described below:
• Some embodiments of the invention comprise a compound of Formula 1 or a pharmaceutically acceptable salt or hydrate thereof, wherein: the bond between X 1 and X 2 may be saturated or unsaturated;
• X 1 is selected from the group consisting of CH 2 , S, C(OH)H and in the case where the bond between X 1 and X 2 is unsaturated, CH;
• X 2 is selected from the group consisting of CH 2 , CH 2 CH 2 and in the case where the bond between
• X 1 and X 2 is unsaturated, CH;
• R 1 is selected from the group consisting of H, alkyl, alkenyl, aryl, arylalkyl, substituted alkyl, substituted alkenyl, substituted aryl or substituted arylalkyl;
• R 2 is CH 3 or COOH;
• R 3 is selected from the group consisting of H, alkyl or NR 3 R 3 taken together is pyrrolidino or piperidino;
• R 4 is selected from the group consisting of H, alkyl, alkenyl, aryl, arylalkyl, substituted alkyl, substituted alkenyl, substituted aryl or substituted arylalkyl
• R 5 is selected from the group consisting of H, alkyl, alkenyl, aryl, arylalkyl, substituted alkyl, substituted alkenyl, substituted aryl or substituted arylalkyl
• n is an integer from 0 to 2.
• the compounds are compounds of Formula 1 wherein X 1 is CH 2 ; X 2 is CH 2 ; R 1 is CH 2 -CH 3 ; R 2 is COOH; R 3 is H; R 4 is H; R 5 is H; n is O (analog 2: Glycyl-L-2-ethylprolyl-L-glutamic acid (“G-2EthylPE”)).
• the compounds are compounds of of Formula 1 where X 1 is CH 2 ; X 2 is CH 2 ; R 1 is CH 2 -CH 2 -CH 3 ; R 2 is COOH; R 3 is H; R 4 is H; R s is H; n is O (analog 3: Glycyl-L-2-propylprolyl-L-glutamic acid (“G-2PropylPE”)).
• the compounds are compounds of Formula 1 where X 1 is CH 2 ; X 2 is CH 2 ; R 1 is benzyl; R 2 is COOH; R 3 is H; R 4 is H; R 5 is H; n is O (5: Glycyl-L-2- benzylprolyl-L-glutamic acid trifluoroacetate (“G-2BenzylPE”)).
• the compounds are compounds of Formula 1 where X 1 is S; X 2 is CH 2 ; R 1 is H; R 2 is COOH; R 3 is H; R 4 is H; R 5 is H; n is O (analog 48: Glycyl- L-4-thiaprolyl-L-glutamic acid trifluoroacetate).
• the compounds are compounds of Formula 1 where X 1 is S; X 2 is CH 2 ; R 1 is H; R 2 is COOH; R 3 is H; R 4 is CH 3 ; R 5 is H; n is O (analog 49: Glycyl-L-thia-5,5-dimethylprolyl-L-glutamic acid (“G-thiadiMePE”)).
• the compounds are compounds of Formula 1 wherein X 1 is CH 2 ; X 2 is CH 2 ; R 1 is H; R 2 is COOH; R 3 is H; R 4 is CH 3 ; R 5 is H; n is O (analog 50: Glycyl- ⁇ DjL ⁇ SjS-dimethylprolyl-L-glutamic acid).
• the compounds are compounds of Formula 1 wherein X 1 is C(OH)H; X 2 is CH 2 ; R 1 is H; R 2 is COOH; R 3 is H; R 4 is H; R 5 is H; n is O (analog 60: Glycyl-trans-4-hydroxy-L-prolyl-L-glutamic acid (“GHypE”))-
• the compounds are compounds of Formula 1 wherein X 1 is CH 2 ; X 2 is CH 2 ; R 1 is H; R 2 is COOH; R 3 is H; R 4 is H; R 5 is H; n is 1 (analog 62: Glycyl-L-homoprolyl-L-Glutamic Acid (“GHomoPE”)).
• GHomoPE Glycyl-L-homoprolyl-L-Glutamic Acid
• the compounds are compounds of Formula 1 wherein the bond between X 1 and X 2 is unsaturated; X 1 is CH; X 2 is CH; R 1 is H; R 2 is COOH; R 3 is H; R 4 is H; R 5 is H; n is O (analog 63: Glycyl-L-3,4-dehydroprolyl-L-glutamic acid trifluoroacetate (“G-3,4-dehydroPB-TFA”)).
• the compounds are compounds of Formula 1 wherein: Xl is CH2; X2 is CH2; Rl is H; R2 is COOH; R3 is H; R4 is H; R5 is CH3; n is O (analog 64: Aminoisobutryl-L-prolyl-L-glutamic acid (“AibPE”)).
• the compounds are compounds of Formula 1 wherein X 1 is CH 2 ; X 2 is CH 2 ; R 1 is H; R 2 is CH 3 ; R 3 is H; R 4 is H; R 5 is H; n is 0 (analog 65: Glycyl-L-prolyl-L-Norvaline ("GP Norvaline”)).
• the compounds are compounds of Formula 1 wherein X 1 is CH 2 ; X 2 is CH 2 CH 2 ; R 1 is H; R 2 is COOH; R 3 is H; R 4 is H; R 5 is H; n is O (analog 66: Glycyl-D,L-pipecolinyl-L-glutamic Acid ("G(D,L)PipE”)).
• the compounds are compounds of Formula 1 wherein X 1 is CH 2 ; X 2 is CH 2 ; R 1 is CH 3 ; R 2 is COOH; NR 3 R 3 taken together is pyrrolidine; R 4 is H; R 5 is H; n is O (analog 67: Pyrrolidinoglycyl-L ⁇ -Methyl-proline-L-Glutamic Acid (“PyrrolidinoG-2MePE”)).
• the invention comprises compounds of Formula 2 or a pharmaceutically acceptable salt or hydrate thereof, wherein R is H or OH.
• the compounds are compounds of Formula 2 where R is H (analog 35: (25 r ,5'R)-[r-(2"-Amino-acetyl)-6'-oxo-l',7'-diazaspiro[4.4]non-7 l -yl]-l,5-pentanedioic acid ("GP-5,5-spirolactamE”)).
• the compounds are compounds of Formula 2 where R is OH (analog 36: (2£,57?,8'R)- and (2S,5 1 R,8'S)-[r-(2"-Amino-acetyl)-8 l -hydroxy-6'-oxo- l',7'-diazaspiro[4.4]non-7'-yl]-l,5-pentanedioic acid ("GP-5,5-hydroxyspirolactamE”)).
• compounds of Formula 3 or a pharmaceutically acceptable salt or hydrate thereof wherein R 1 is selected from the group consisting of H, alkyl, alkenyl, aryl, arylalkyl, substituted alkyl, substituted alkenyl, substituted aryl or substituted arylalkyl; R 2 is CH 3 or COOH;
• R 3 is selected from the group consisting of H, alkyl or NR 3 R 3 taken together is pyrrolidino or piperidino;
• R 4 is selected from the group consisting of H, alkyl, alkenyl, aryl, arylalkyl, substituted alkyl, substituted alkenyl, substituted aryl or substituted arylalkyl;
• n is an integer from O to 2
• the compounds are compounds of Formula 3 where R 1 is H; R 2 is COOH; R 3 is H; R 4 is H; n is O (analog 61: Glycyl-L-2-Pyroglutamyl-L- Glutamic Acid Hydrochloride ("GpyroE.HCl”)).
• the invention comprises compounds of Formula 4 or a pharmaceutically acceptable salt or hydrate thereof, wherein R 1 is selected from the group consisting of H, alkyl, alkenyl, aryl, arylalkyl, substituted alkyl, substituted alkenyl, substituted aryl or substituted arylalkyl.
• R 1 is CH 3 (analog 68: Glycyl-L-2-Methylproline("G-2MeP")).
• the invention comprises a compound of Formula 4, or a pharmaceutically acceptable salt or hydrate thereof, wherein R is methyl.
• Other aspects of the invention provide pharmaceutically acceptable salts of the compounds described in Formulas 1-4.
• this invention provides pharmaceutical compositions comprising a pharmaceutically acceptable excipient and a therapeutically effective amount of at least one compound of this invention. These compositions find use as anti-apoptotic and anti-necrotic agents and for other conditions involving neural degeneration or injury.
• this invention provides methods of treating an animal having a disease or injury capable of treatment by administration of a suitable compound of Formulas 1-4, comprising administration to that animal of at least one compound of this invention, optionally in conjunction with at least one other conventional therapeutic agent for the disease being treated.
• the animal to be treated is a human.
• this invention provides methods of synthesizing, formulating and preparing pharmaceutical preparations comprising compounds of Formulas l-4of this invention.
• compositions of the invention include the use of compounds of the invention in treatment or prevention of cell damage, degeneration and/or death in mammals in response to injury or disease. Some embodiments comprise delivering a composition containing a compound of the invention to an animal suffering from neural degeneration, and in some cases, conditions involving apoptotic and necrotic cell death. In some embodiments, compositions are desirable to treat an injury or disease of the CNS affecting or liable to affect brain cells. Compositions are provided that can also include one or more other agents that promote neural regeneration, decrease cell degeneration or death, or are neuroprotective.
• Such other agents can be selected from the group consisting of for example, growth factors and associated derivatives, e.g., insulin-like growth factor-I (IGF-I), insulin-like growth factor-II (IGF-II), the tripeptide GPE, transforming growth factor- ⁇ l, activin, growth hormone, nerve growth factor, growth hormone binding protein, and/or IGF-binding proteins.
• growth factors and associated derivatives e.g., insulin-like growth factor-I (IGF-I), insulin-like growth factor-II (IGF-II), the tripeptide GPE, transforming growth factor- ⁇ l, activin, growth hormone, nerve growth factor, growth hormone binding protein, and/or IGF-binding proteins.
• Other aspects of the invention include compositions and methods of promoting fasiculation of axons. By promoting formation of nerve bundles, compounds of the invention can be useful in treating conditions in which nerve processes (axons and/or dendrites) have become severed, such as in sharp force injuries,
• compositions and methods to treat or prevent cell damage and death in response to injury and disease comprise administration of a therapeutic amount of a compound of the invention alone or in combination with other agents, after the insult.
• a therapeutic amount of a compound of the invention alone or in combination with other agents, after the insult.
• compounds of the invention can be used either alone or in combination with other agents to prevent adverse effects of planned brain injury.
• Such conditions include CABG or other planned surgeries such as brain surgery, vascular surgery or other interventions that can lead to decreased perfusion of the nervous system.
• adverse neurological effects may be ameliorated.
• the present invention is broadly based upon the applicant's finding that compounds of the invention can protect cells, particularly nerve cells, against damage, loss of neurites, and/or apoptotic or necrotic cell death. It is herein demonstrated that compounds of the invention exhibit neuroprotection in cell culture models of neurodegenerative disease and can therefore be an effective addition or alternative to conventional therapies for neural degeneration.
• compounds of the invention can be used as an effective therapy for a variety of neurological diseases, including hypoxia, ischemia and neurotoxin-induced nerve damage.
• compounds of the invention can be used in the absence of any particular neurological deficit to promote neurite outgrowth and fasiculation of nerves.
• administration of compounds of the invention may be an effective way of promoting neurite regeneration.
• compositions and methods of the invention find use in the treatment of animals, such as human patients, suffering from neural injury or disease. Still more generally, the compositions and methods of the invention find use in the treatment of mammals, such as human patients, suffering from nerve damage or potential apoptotic and/or necrotic cell death, due to injuries and diseases.
• G-2MethylPE, G-2AllylPE, diketopiperazine derivatives of GPE, macrocyclic analogs of GPE and L-AIa-PE In studies of GPE and the other GPE analogs G-2MethylPE, G-2AllylPE, diketopiperazine derivatives of GPE, macrocyclic analogs of GPE and L-AIa-PE, a general observation has been made.
• the existence of neuroprotection is independent of the type of insult applied.
• neurodegenerative effects of hypoxia/ischemia and toxic injury can be mitigated or prevented by GPE and GPE analogs previously disclosed.
• parallel neuroprotective effects of the above previously disclosed GPE analogs are also found in in vivo systems.
• Specific conditions and diseases characterised by neuronal degeneration, apoptosis and/or necrosis include but are not limited to Alzheimer's disease, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis, spinal muscular atrophy, peripheral neuropathy, Creutzfeldt-Jakob disease, AIDS dementia, progressive supranuclear palsy, myelinopathia centralis diffusa (vanishing white matter disease), chronic neurodegenerative disease, Huntington's disease, stroke, ischemic injury, hypoxic injury, reperfusion injury, head injury, penetrating brain injury, CNS trauma, epilepsy, cerebral ischemia, glaucoma, retinal disorders, optic neuropathy, optic neuritis, Down's syndrome, encephalomyelitis, meningitis, panencephalitis, neuroblastoma, schizophrenia and depression.
• Each of the above conditions exhibits pathophysiological findings and symptoms that are mimicked by neurotoxicity associated with glutamate toxicity for which GPE and GPE analogs
• compounds of the invention can have application in the induction of nerve bundle formation following insult in the form of trauma, toxin exposure, asphyxia or hypoxia- ischemia. Additionally, compounds of the invention can have application in the treatment or prevention of apoptosis or other forms of neurodegeneration, necrosis or damage in response to injury or disease in the form of cancers, viral infections, autoimmune diseases, neurological diseases and injuries and cardiovascular diseases.
• Treatment can be given before an injury, for example, before elective surgery.
• relevant elective procedures include neural surgery, in which retraction of lobes of the brain can lead to cerebral oedema, or heart operations, such as valve replacement, in which inevitable small emboli are said to lead to detectable impairment of brain function in some 75% of cases.
• the neureoprotective activity of compounds of the invention can be measured by in vivo using cell counts by methods known to those skilled in the art including the methods of Klempt et al (Klempt et al, 1992, Molecular" Brain Research: 13: 93-101), microscopic examinations of morphology, cell counts of surviving and dead neurons stained with thionin/fuchsin and the like.
• Effects of compounds of the invention can also be measured in vitro using an assay for neurite outgrowth, mass spectroscopy, immunological, or chromatographic methods known in the art. These methods have been well characterized and validated in numerous experimental systems and therefore are predictive of neuroprotective effects in human cells and in animal systems including human beings.
• CNS damage can for example be measured clinically by the degree of permanent neurological deficit cognitive function, and/or propensity to seizure disorders.
• histological techniques suitable for measuring effects in vivo Some methods suitable for in vivo assessment can be found in US Patent No. 7,041,314, PCT International Patent Application No: PCT/US02/16361 filed 24 May 2002, US Application No: 11/314,424 filed 20 December 2005, US Application No: 11/315,784 filed 21 December 2005, US Patent Application No: 11/398,032 filed 4 April 2006 and US Provisional Patent Application No: 60/782,148 filed 14 March 2006.
• the therapeutic ratio of a compound is understood to be the ratio of (1) the mean dose that causes adverse side effect over (2) the mean dose that causes a desirable therapeutic effect. Thus, for compounds for which have therapeutic effects at relatively low doses and undesirable side effects at high doses, the therapeutic ratio is >1.
• Therapeutic ratio can be determined, for example, by comparing the dose that produces significant weight loss (or other observable side-effect) divided by the dose that produces anti-apoptotic and anti-necrotic activity in a suitable in vivo animal species such as the rat or mouse. Suitable models include a hypoxic-ischemic injury (Sirimanne et al, 1994 Journal of Neuroscience Methods: 55: 7-14) and experimental immune encephalomyelitis (Mendel et al, 1995 Eur. J. Immunol: 25: 1951-1959).
• Compounds of the invention can be administered as part of a medicament or pharmaceutical preparation. This can involve combining a compound of the invention with any pharmaceutically appropriate carrier, adjuvant or excipient. The selection of the carrier, adjuvant or excipient will of course usually be dependent upon the route of administration to be employed. In general, compounds of this invention will be administered in therapeutically effective amounts by any of the usual modes known in the art, either singly or in combination with other conventional therapeutic agents for the disease being treated. A therapeutically effective amount can vary widely depending on the disease or injury, its severity, the age and relative health of the animal being treated, the potency of the compound(s), and other factors.
• therapeutically effective amounts of compounds of this invention can range from 0.001 to 100 milligrams per kilogram mass of the animal, with lower doses such as 0.001 to 0.1 mg/kg being appropriate for administration through the cerebrospinal fluid, such as by intracerebroventricular administration, and higher doses such as 1 to 100 mg/kg being appropriate for administration by methods such as oral, systemic (e.g. transdermal), or parenteral (e.g. intravenous) administration.
• a person of ordinary skill in the art will be able without undue experimentation, having regard to that skill and this disclosure, to determine a therapeutically effective amount of a compound of this invention for a given disease or injury.
• Compounds of the invention can be administered peripherally via any peripheral route known in the art. These can include parenteral routes for example injection into the peripheral circulation, subcutaneous, intraorbital, ophthalmic, intraspinal, intracisternal, topical, infusion (using e.g. slow release devices or minipumps such as osmotic pumps or skin patches), implant, aerosol, mnaiauon, scari ⁇ cauon, intraperitoneal, intracapsular, intramuscular, intranasal, oral, buccal, transdermal, pulmonary, rectal or vaginal.
• the compositions can be formulated for parenteral administration to humans or other mammals in therapeutically effective amounts (e.g. amounts which eliminate or reduce the patient's pathological condition) to provide therapy for the neurological diseases described above.
• compounds of this invention when administered as anti-apoptotic and anti-necrotic agents, compounds of this invention will be administered orally.
• the amount of a compound of this invention in the composition can vary widely depending on the type of composition, size of a unit dosage, kind of excipients, and other factors well known to those of ordinary skill in the art.
• the final composition can comprise from 0.0001 percent by weight (% w) to 10% w of the compound of this invention, preferably 0.001% w to 1% w, with the remainder being the excipient or excipients.
• Other convenient administration routes include subcutaneous injection (e.g. dissolved in a physiologically compatible carrier such as 0.9% sodium chloride) or direct administration to the CNS.
• a compound can be injected directly into a site of neural damage.
• routes of administration can be especially desired in situations in which perfusion of that location is compromised either by decreased vascular perfusion or by decreased cerebral spinal fluid (CSF) flow to that area. Examples include administration by lateral cerebroventricular injection or through a surgically inserted shunt into the lateral cerebro ventricle of the brain of the patient, intraveneously, direct injection into the desired location or other routes.
• the effective amount of compound in the CNS can be increased by administration of a prodrug form of a compound, which comprises a compound of the invention and a carrier, where the carrier is joined to a compound of the invention by a linkage which is susceptible to cleavage or digestion within the patient. Any suitable linkage can be employed which will be cleaved or digested following administration.
• inhibiting neurodegeneration and/or restoring nerve function in an animal can comprise administering a therapeutic amount of a compound of the invention in combination with another neuroprotective agent, selected from, for example, GPE, analogs of GPE described in US Patent No. 7,041,314, PCT International Patent Application No:
• Additional members of the FGF family include, for example, int-2, fibroblast growth factor homologous factor-1 (FHF-I), FHF-2, FHF-3 and FHF-4, karatinocyte growth factor 2, glial-activating factor, FGF-IO and FGF-16, ciliary neurotrophic factor, brain derived growth factor, neurotrophin 3, neurotrophin 4, bone morphogenetic protein 2 (BMP-2), glial-cell line derived neurotrophic factor, activity-dependant neurotrophic factor, cytokine leukaemia inhibiting factor, oncostatin M, interleukm), ⁇ -, /3-, ⁇ -, or consensus interferon, and TNF- ⁇ .
• FHF-I fibroblast growth factor homologous factor-1
• FHF-2 fibroblast growth factor homologous factor-1
• FHF-2 fibroblast growth factor homologous factor-1
• FHF-2 fibroblast growth factor homologous factor-1
• FHF-2 fibroblast growth factor homologous factor-1
• FHF-2
• neuroprotective therapeutic agents include, for example, clomethiazole; kynurenic acid, Semax, tacrolimus, L-threo-l-phenyl-2-decanoylamino- 3-morpholino-l-propanol, andrenocorticotropin-(4-9) analog [ORG 2766] and dizolcipine (MK- 801), selegiline; glutamate antagonists such as, NPS1506, GV1505260, MK-801, GV150526; AMPA antagonists such as 2,3-dihydroxy-6-nitro-7-sulfamoylbenzo(f)quinoxaline (NBQX), LY303070 and LY300164; anti-inflammatory agents directed against the addressin MAdCAM-I and/or its integrin ⁇ 4 receptors ( ⁇ 4 ⁇ l and ⁇ 4 ⁇ 7), such as anti-MAdCAM-lmAb MECA-367 (ATCC accession no. HB-9478).
• sustained-release compositions include semi-permeable polymer matrices in the form of shaped articles, e.g., films, or microcapsules.
• Sustained-release matrices include polylactides (U.S. Pat. No. 3,773,919; EP 58,481), copolymers of L-glutamic acid and gamma-ethyl -L-glutamate (Sidman et al., 1983, Biopolymers: 22: 547-56), poly(2-hydroxyethyl methacrylate) (Langer et al, 1981, J. Biomed. Mater.
• Sustained-release compositions also include a liposomally entrapped compound. Liposomes containing the compound are prepared by methods known per se: DE 3,218,121, EP 52,322, EP 36,676, EP 88,046, EP 143,949, EP 142,641, Japanese Pat. Appln. 83-118008, U.S. Pat. Nos. 4,485,045 and 4,544,545, and EP 102,324.
• the liposomes are of the small (from or about 200 to 800 Angstroms) unilamellar type in which the lipid content is greater than about 30 mol percent cholesterol, the selected proportion being adjusted for the most efficacious therapy.
• the compound is formulated generally by mixing each at the desired degree of purity, in a unit dosage injectable form (solution, suspension, or emulsion), with a pharmaceutically, or parenterally, acceptable carrier, i.e., one that is non-toxic to recipients at the dosages and concentrations employed and is compatible with other ingredients of the formulation.
• the formulations are prepared by contacting the compound uniformly and intimately with liquid carriers or finely divided solid carriers or both. Then, if necessary, the product is shaped into the desired formulation.
• the carrier is a parenteral carrier, more preferably a solution that is isotonic with the blood of the recipient.
• carrier vehicles include water, saline, Ringer's solution, a buffered solution, and dextrose solution.
• Nonaqueous vehicles such as fixed oils and ethyl oleate are also useful herein.
• a carrier suitably contains minor amounts of additives such as substances that enhance isotonicity and chemical stability.
• Such materials are non-toxic to recipients at the dosages and concentrations employed, and include buffers such as phosphate, citrate, succinate, acetic acid, and other organic acids or their salts; antioxidants such as ascorbic acid; low molecular weight (less than about ten residues) polypeptides, e.g., polyarginine or tripeptides; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; glycine; amino acids such as glutamic acid, aspartic acid, histidine, or arginine; monosaccharides, disaccharides, and other carbohydrates including cellulose or its derivatives, glucose, mannose, trehalose, or dextrins; chelating agents such as EDTA; sugar alcohols such as mannitol or sorbitol; counter-ions such as sodium;
• a compound is typically formulated in such vehicles at a pH of from or about 4.5 to 8. It will be understood that use of certain of the foregoing excipients, carriers, or stabilizers will result in the formation of salts of the compound.
• the final preparation can be a stable liquid or lyophilized solid.
• Formulations of the compound in pharmaceutical compositions can also include adjuvants.
• Typical adjuvants which can be incorporated into tablets, capsules, and the like are a binder such as acacia, corn starch, or gelatin; an excipient such as microcrystalline cellulose; a disintegrating agent like corn starch or alginic acid; a lubricant such as magnesium stearate; a sweetening agent such as sucrose or lactose; a flavouring agent such as peppermint, wintergreen, or cherry.
• a binder such as acacia, corn starch, or gelatin
• an excipient such as microcrystalline cellulose
• a disintegrating agent like corn starch or alginic acid
• a lubricant such as magnesium stearate
• a sweetening agent such as sucrose or lactose
• a flavouring agent such as peppermint, wintergreen, or cherry.
• the dosage form is a capsule, in addition to the above materials, it can also contain
• a syrup or elixir can contain the active compound, a sweetener such as sucrose, preservatives like propyl paraben, a colouring agent, and a flavouring agent such as cherry.
• Sterile compositions for injection can be formulated according to conventional pharmaceutical practice. For example, dissolution or suspension of the active compound in a vehicle such as water or naturally occurring vegetable oil like sesame, peanut, or cottonseed oil or a synthetic fatty vehicle like ethyl oleate or the like may be desired. Buffers, preservatives, antioxidants, and the like can be incorporated according to accepted pharmaceutical practice.
• the compounds used For injection, intraventricular administration, and other invasive routes of administration, the compounds used must be sterile.
• Sterility can be accomplished by any method known in the art, for example filtration through sterile filtration membranes (e.g., 0.2 micron membranes).
• Therapeutic compositions generally are placed into a container having a sterile access port, for example, an intravenous solution bag or vial having a stopper able to be pierced by a hypodermic injection needle.
• a pharmaceutical formulation ordinarily will be stored in unit or multi-dose containers, for example, in sealed ampoules or vials, as an aqueous solution or as a lyophilized formulation for reconstitution.
• a lyophilized formulation 10 mL vials are filled with 5 mL of sterile-filtered 1% (w/v) aqueous solution of compound, and the resulting mixture is lyophilized.
• the infusion solution is prepared by reconstituting the lyophilized compound using bacteriostatic Water-for-Injection. It can be readily appreciated that other dosage forms and types of preparations can be used, and all are considered to be part of this invention.
• tripeptides 4 and 5 incorporating a 2-allylproline and a 2- benzylproline unit respectively, Boc and f-butyl protecting groups were used.
• coupling of acids 26 and 27 with di-/ert-butyl glutamate 29 gave tripeptides 33 and 34 affording tripeptides 4 and 5 as trifluoroacetate salts after deprotection with TFA.
• R 1 CH 2 CH 2 CH 3
• Another method of conformationally constraining a peptide is to synthesize a peptidomimetic containing a spirolactam ring system. It has been suggested that a spirolactam ring system may lock a compound into predominantly one conformation and different ring systems have been shown to mimic both b- and g-turns (Hinds et al J. Med. Chem. 1991, 43, 1777; Fernandez et al. J. Org. Chem. 2002, 67, 7587; Kang J. Phys. Chem. 2002, 106, 2074). A spirocyclic g-lactam bridge can be formed between the 2-position of the proline residue and the nitrogen of the glutamate residue in GPE thus, presenting an opportunity to investigate the effect of such conformational restriction in GPE analogs.
• the pyrrolidine ring of proline is capable of adopting two distinct conformations. These down- and up-puckered conformations are defined as occurring when C g and the carbonyl group of proline lie on the same and opposite sides respectively, of the plane defined by C d , N and C a .
• the presence of a sulfur atom in the proline ring can affect the bond angles and bond lengths, in some cases altering the proline ring conformation.
• Kang found that replacement of the proline residue in AcProNHMe with 4-thiaproline 40 [(/?)-thiozolidine-4-carboxylic acid (Thz)] resulted in a more puckered conformation (Kang 2002).
• Boc-protected methyl D,L-5,5-dimethylprolinate 43 was prepared from nitrile 44 (Scheme
• Nitrile 44 was prepared as described in the literature (Ono et al. J. Org, Chem., 1985, 50 3692) however, subsequent hydrolysis of the nitrile moiety and hydrogenation of the intermediate N- oxide as described (Magaard et al. Tetrahedron Lett. 1993, 34, 381) was concomitant with acid catalysed methyl migration yielding a mixture of 45 and 46. (6:4 ratio, 1 H ⁇ MR). Extensive modification of the hydrolysis reaction could not overcome the formation of N-methyl compound 45. It is interesting that this unwanted reaction has not been reported during the synthesis of 5,5- dimethylproline that has been described by several research groups (An et al. J. Am. Chem Soc.
• the tripeptides 48-50 were synthesized in a similar fashion to the 2-alkylproline analogs (Scheme 6). Coupling of the 4-thia- ⁇ roline building block 40 to Boc-glycine 17 was carried out using a mixed anhydride activation procedure whereas the more hindered 5,5-dimethyl-4-thia- proline ti required use ⁇ i me more reactive acid fluoride 51 to afford 53. In the case of the 5,5- dimethylproline 43 the Boc group was removed with trifluoroacetic acid before BoPCl coupling with Boc-glycine 17 to afford 54. Hydrolysis of the methyl ester then afforded acid 55 in preparation for the second peptide coupling.
• tripeptide 48 was removed using trifluoroacetic acid to give tripeptide 48 as the trifluoroacetate salt whereas for the deprotection of 58, treatment with trifluoroacetic acid followed by hydrogenolysis afforded tripeptide 50.
• 57, 58 BoPCl, /-Pr 2 EtN, CH 2 Cl 2 , 28, rt, 7h, 57, 68%, 58, 24h, 67%; (vi) CF 3 CO 2 H, Et 3 SiH, CH 2 Cl 2 , rt, 4h,
• NMR Nuclear Magnetic Resonance
• Optical rotations were measured at 20 0 C on a Perkin Elmer 341 polarimeter using 10 cm path length cells and are given in units of 10 "1 degcm 2 g "1 . Samples were prepared in the solvent indicated at the concentration specified (measured in g/100 cm 3 ).
• Bis(2-oxo-3-oxazolidinyl)phosphinic chloride (0.20 g, 0.80 mmol) was added and the solution stirred for 19.5 h, then washed successively with 10% aqueous hydrochloric acid (35 cm 3 ) and saturated aqueous sodium hydrogen carbonate (35 cm 3 ), dried (MgSO 4 ), filtered and evaporated to dryness in vacuo.
• Bis(2-oxo-3-oxazolidinyl)phosphinic chloride (0.42 g, 1.66 mmol) was added and the solution stirred for 18.5 h, then washed successively with 10% aqueous hydrochloric acid (70 cm 3 ) and saturated aqueous sodium hydrogen carbonate (70 cm 3 ), dried (MgSO 4 ), filtered and evaporated to dryness in vacuo.
• ester 22 (0.11 g, 22%) as a pale yellow oil: [ ⁇ ] D +105.3 (c 0.99 in CH 2 Cl 2 ); V ⁇ x (filmycrn 1 3419, 3061, 3028, 2977, 2873, 1799, 1739, 1715, 1655, 1582, 1497, 1454, 1432, 1392, 1366, 1330, 1250, 1167, 1121, 1093, 1049, 1026, 948, 915, 865, 819, 765, 736, 706 and 653; ⁇ 5k (3OO MHz; CDCl 3 ) 1.08-1.12 (IH, m, PrOy-H 4 H 13 ), 1.47 [9H, s, C(CH 3 ) 3 ], 1.67-1.72 (IH, m, Pro ⁇ -H A H B ), 2.01-2.17 (2 ⁇ , m,
• ester 20 (0.12 g, 0.34 mmol) in dioxane (7 cm 3 ) was added dropwise 1 M aqueous NaOH (2.06 cm 3 , 2.06 mmol) and the mixture stirred for 20 h at room temperature.
• Dichloromethane 25 cm 3 was then added and the organic layer extracted with saturated aqueous sodium bicarbonate (3 x 25 cm 3 ).
• ester 21 (0.039 g, 0.12 mmol) in dioxane (2.4 cm 3 ) was added dropwise 1 M aqueous NaOH (0.72 cm 3 , 0.72 mmol) and the mixture was stirred for 16 h at room temperature.
• Triethylamine (0.50 cm 3 , 3.59 mmol) was added dropwise to a solution of dipeptide 23 (0.36 g, 1.12 mmol) and L-glutamic acid dibenzyl ester p-toluenesulphonate 28 (0.73 g, 1.46 mmol) in dichloromethane (60 cm 3 ) under nitrogen at room temperature, and the reaction mixture stirred for 10 min.
• Bis(2-oxo-3-oxazolidinyl)phosphinic chloride (0.37 g, 1.41 mmol) was added and the colourless solution stirred for 17h.
• Tripeptide 30 was shown to adopt exclusively the trans conformer by NMR: R f 0.55 (EtOAc); [ ⁇ ] D -41.9 (c 0.29 in CH 2 Cl 2 ); V 1113x (filmycrn 1 3583, 3353 br, 2950, 1734, 1660, 1521, 1499, 1454, 1429, 1257, 1214, 1188, 1166, 1051, 911, 737 and 697; o ⁇ (400 MHz; CDCl 3 ; Me 4 Si) 1.64 (3H, s, Pro ⁇ -CH 3 ), 1.72 (IH, dt, J 12.8, 7.6 and 7.6, Pro ⁇ -H 4 H B ), 1.92 (2H, 5 lines, J 6.7, Pro ⁇ -H 2 ), 2.04 (IH, 6 lines, J 7.3 Glu ⁇ - H A ⁇ .
• Bis(2-oxo-3-oxazolidinyl)phosphinic chloride (0.29 g, 1.14 mmol) was added and the solution stirred for 2 h, warmed to room temperature and further stirred for 17.5h. The solution was washed successively with 0.5 M aqueous hydrochloric acid (10 cm 3 ) and saturated aqueous sodium hydrogen carbonate (10 cm 3 ), dried (MgSO 4 ), filtered and evaporated in vacuo to form a light orange gum.
• Bis(2-oxo-3-oxazolidinyl)phosphinic chloride (0.08 g, 0.30 mmol) was added and the solution stirred for 17h, then washed successively with 10% aqueous hydrochloric acid (12 cm 3 ) and saturated aqueous sodium hydrogen carbonate (12 cm 3 ), dried (MgSO 4 ), filtered and evaporated to dryness in vacuo.
• Tripeptide 1 was shown to adopt the trans conformation by NMR analysis: mp 144 °; [ ⁇ ] D -52.4 (c 0.19 in H 2 O); S n (400 MHz; D 2 O) 1.62 (3H, s, Pro ⁇ -CH 3 ), 1.97-2.25 (6H, m, Pro ⁇ -H 2 , Pro ⁇ -H 2 and Glu ⁇ -H 2 ), 2.45 (2H, t, J 7.3, Glu ⁇ -H 2 ), 3.62-3.70 (2H, m, Pro ⁇ -H 2 ), 3.96 (IH, d, J 16.5, Gly ⁇ - H 4 Hs), 4.02 (IH, d, J 16.4, Gly ⁇ -H A H B ) and 4.28 (1 ⁇ , dd, J 8.4 and 4.7, Glu ⁇ - ⁇ ); ⁇ c (100 MHz; D 2 O) 19.9 (CH 3 , Pro ⁇ -CH 3 ), 23.0 (CH 2 , Pro ⁇ -C), 26.9 (CH 2 , Glu ⁇
• Tripeptide 2 was shown to be exclusively the trans conformer by x H and 13 C NMR analysis: mp 82-85 0 C; [ ⁇ ] D -43.8 (c 0.1 in MeOH); ⁇ H (400 MHz; D 2 O) 0.86 (3 H, t, J 7.4, CH 3 ), 1.94-2.40 (8 H, m, CH 2 CH 3 , Glu ⁇ -H 2 , Pro ⁇ -H 2 and Pro- ⁇ H 2 ), 2.52-2.56 (2H, m, Glu ⁇ -H 2 ), 3.55-3.61 (1 H, td, / 6.9 and 9.7, Pro ⁇ -H A H B ), 3-75-3.80 (1 H, m, Pro ⁇ -H A H B ), 4.08 (2H, q, J 16.6, Gly ⁇ -H 2 ) and 4.44 (1 H,
• Tripeptide 3 was shown to be exclusively the trans conformer by NMR analysis: mp 278-280 0 C (dec); [ ⁇ ] D -16.7 (c 0.18 in H 2 O); ⁇ a (300 MHz; D 2 O) 0.98 (3H, t, CH 2 CH 3 ), 1.09 (1 ⁇ , m, CH 4 ⁇ B C ⁇ 3 ), 1.44 (IH, m, CH ⁇ H B CH 3 ), 1.82-2.31 (8H, m, Pro ⁇ -H 2 , Pro ⁇ -H 2 , Glu ⁇ -H 2 and CH 2 CH 2 CH 3 ), 2.40 (IH, m, Glu ⁇ -H 2 ), 3.55-3.63 (IH, m, Pn ⁇ -H 4 Hu), 3.80 (IH, m, Pro ⁇ -H A Hs), 4.03 (1 ⁇ , d, J 16.6, Gly ⁇ -Ms), 4.15 (IH, d, J 16.6, Gly ⁇ -H A H ⁇ ) and 4.27 (1 ⁇ , dd,
• Tripeptide 5 was shown to be a 90:10 trans :cis mixture of conformers by 1 H NMR analysis (the ratio was estimated from the relative intensities of the double doublets and multiplet at ⁇ 4.51 and 4.33, assigned to the Glu ⁇ -H protons of the major and minor conformers, respectively): mp 73-82 0 C; [ ⁇ ] D +41.0 (c 1.61 in MeOH); S n (300 MHz; D 2 O) 1.27-1.39 (IH, m, PrOy-H 4 H] 3 ), 1.68-1.83 (IH, m, Pro ⁇ -H A H S ), 2.07-2.42 (4 ⁇ , m, Pro ⁇ -H 2 and Glu ⁇ -H 2 ), 2.57 (2H, t, / 7.1, Glu ⁇ -H 2 ), 2.82-2.92 (IH, m, Pro ⁇ -H ⁇ H B ), 3.24 (IH, d, J 13.3, PhCH 4 H B ), 3.50-3.59 (IH,
• Hydroxyspirolactam 38 was shown to be a 7:3 mixture of diastereomers by 1 H NMR analysis. The ratio was estimated from the relative intensities of the multiplet at ⁇ 4.76-4.79 and the doublet of doublets at ⁇ 5.00, assigned to the 2-H protons of the minor and major isomers, respectively) with the isomers being inseparable: [ ⁇ ] D -44.4 (c 0.90 in MeOH); v max (filmycm '1 3410, 3064, 3034, 2953, 2881, 2083, 1718, 1649, 1498, 1454, 1332, 1267, 1215, 1170, 1121, 1082, 1048, 1028, 1003, 984, 909, 776, 736 and 698; S n (400 MHz; CDCl 3 ) 1.74-1.77 * (0.3H, m, 9'- HM B ), 1.93-2.04 (1.3H, m, 9'-E A H B and 3'-H/H B
• Spirolactam 36 was shown to be a 7:3 mixture of two diastereomers by 1 H NMR analysis (the ratio was estimated from the relative intensities of the doublet of doublets at ⁇ 4.47 and 4.53, assigned to 2-H of the minor and major isomers, respectively): mp 216-218 0 C (dec); [ ⁇ ] D +0.86 [c 0.35 in MeOH-H 2 O (1:1)]; ⁇ (400 MHz; D 2 O) 2.10-2.46 (9H, m, 9'-H A H B , 4'-H 2 , 3'- H 2 , 3-H 2 and 4-H 2 ), 2.65* (0.3H, dd, J 13.8 and 7.0, 9'-HAH 5 ), 2.75 (0.7 ⁇ , dd, J 13.6 and 6.2, 9'- H A H B ), 3.55-3.61 (1 ⁇ , m, 2'-H A E.
• Nitrile 44 (Magaard et al. Tetrahedron Lett. 1993, 34, 381) (2 g, 14.3 mmol) was dissolved in 32% hydrochloric acid (6 cm 3 ) and heated to 50 0 C for 5h. Evaporation of the solvent afforded a residue that was dissolved in methanol:water (1:1, 30 cm 3 ) and hydrogenated over 10% palladium on activated carbon (0.3 g) under 44 p.s.i of hydrogen for 2Oh.
• N-Methylmorpholine (1.56 cm 3 , 14.2 mmol) and di-te/Y-butyldicarbonate (3.1 g, 14.2 mmol) were added and the reaction was heated at reflux under nitrogen for 48 h. After cooling to room temperature the reaction mixture was washed with water, 1 M aqueous hydrochloric acid (2 x 30 cm 3 ), brine and dried (MgSO 4 ). The aqueous layer was concentrated in vacuo to give methyl N- methyl-5-methylprolinate 47 (1.093 g, 42%, 4 steps) as its hydrochloride salt.
• Ethyl chlorofomate (0.048 g, 0.445 mmol) was added dropwise to a solution of acid 52 (0.129 g, 0.445 mmol) and triethylamine (0.050 g, 0.49 mmol) in dichloromethane (3 cm 3 ) at 0 0 C.
• the solution was stirred for 35 mins at 0 0 C then a solution of glutamic acid ⁇ i-tert-butyl ester hydrochloride 29 (0.132 g, 0.445 mmol) and triethylamine (0.050 g, 0.49 mmol) in dichloromethane (3 cm 3 ) was added.
• Trifluoroacetic acid (1 cm 3 ) was added to a stirred solution of protected tripeptide 56 (0.128 g, 0.241) and triethylsilane (0.084 g, 0.723 mmol) in dichloromethane (3 cm 3 ). The resultant solution was stirred for 4 h at room temperature and the volatiles removed in vacuo. Purification of the residue by chromatography (reverse phase Q 8 , water, 10-20% acetonitrile:water) and lyophilisation gave 48 (0.066 g, 61%) as a hygroscopic off white solid.
• Tripeptide 49 was shown to be a 85:15 cis: trans mixture of conformers by 1 H NMR analysis (the ratio was estimated from the integration of the doublets at ⁇ 4.95 and 5.02 and assigned to the Pa-H protons of the major and minor conformers respectively): mp 145-150 0 C; [a]o -75 (c 0.064 in water); 4 ⁇ (300 MHz; D 2 O) 1.84 (2.55H, s, P ⁇ -CH 3 ).
• Trifluoroacetic acid (1 cm 3 ) was added to a stirred solution of carbamate 43 (0.584 g, 2.27 mmol) in dichloromethane (6 cm 3 ). The solution was stirred for 2h after which time the volatiles were removed in vacuo and traces of trifluoroacetic acid were removed by placing the sample on an oil pump for 2h.
• Dipeptide 54 was shown to be 80:20 cis:trans mixture of conformers by 1 H NMR analysis (the ratio was estimated from the integration of the chemical shifts at ⁇ 4.28 and 4.46 assigned to the Pro ⁇ -H protons of the major and minor conformers respectively): S n (300 MHz; CDCl 3 ) 1.26 (2.4H, s, Pro ⁇ -CH 3 ), 1.28 [9H, s, C(CH 3 ) 3 ], 1.31 * (0.6H, s, Pro ⁇ -CH 3 ), 1.44 * (0.6H, s, Pro ⁇ -CH 3 ), 1.46 (2.4H, s, Pro ⁇ -CH 3 ), 1.59-2.15 (4H, m, Pro ⁇ -H 2 , Pro ⁇ -H 2 ), 3.37 (0.8H, dd, J 16.7 and 3.3, GIyCt-H 4 H 13 ), 3.57 * (0.6H, s, Pr 0 Ct-CO 2 CH 3 ), 3.61 (2.4H, s, Pro ⁇ -CO 2
• Acid 55 was shown to be an 80:20 cisitrans mixture of conformers by 1 H NMR analysis (the ratio was estimated from the integration of the broad singlets at ⁇ 5.81 and 5.66 assigned to the GIyN-H protons of the major and minor conformers respectively): b ⁇ (300 MHz; CDCl 3 ) 1.40 (2.4H, s, Pro ⁇ -CH 3 ), 1.43 [7.2H, s, C(CHs) 3 ], 1-44 * [1.8H, s, C(CH 3 ) 3 ], 1.47 * (0.6H, s, Pro ⁇ -CH 3 ), 1.58 * (0.6H, s, Pro ⁇ -CH 3 ), 1.61 (2.4H 5 s, Pro ⁇ -CH 3 ), 1.74-2.33 (4H, m, Pro ⁇ -H 2 , Pro ⁇ -H 2 ), 3.37 (0.8H, dd, J 16.7 and 3.3, Gly ⁇ - H A R B ), 3.65 (0.8H, dd, J 16.8 and 3.6, G
• Tripeptide 58 was shown to be 85:15 cisitrans mixture of conformers by 1 H NMR analysis (the ratio was estimated from the integration of the chemical shifts at ⁇ 5.31-5.38 and 5.48 assigned to the GIy-NH protons of the major and minor conformers respectively): b ⁇ (300 MHz; CDCl 3 ) 1.41 [9H, s, C(CH 3 )J, 1.44 (2.55H, s, Pro ⁇ -CH 3 ), 1.52 * (0.45H, s, Pro ⁇ -CH 3 ), 1.54 * (0.45H, s, Pro ⁇ -CH 3 ), 1.64 (2.55H, s, Pro ⁇ -CH 3 ), 1.67 (2.55H, s, Pro ⁇ -CH 3 ), 1.70-2.24 (6H, m, Pro ⁇ -H 2 , Pro ⁇ -H 2 , Glu ⁇ -H 2 ), 2.35-2.45 (2H, m, GlUy-H 2 ), 3.58-3.69 (0.85H, m
• Tripeptide 50 was shown to be a 72:28 cis:trans mixture of conformers by 1 H NMR analysis (the ratio was estimated from the integration of the chemical shifts at ⁇ 3.57 and 4.15-4.16 assigned to the Gly ⁇ -H protons of the major and minor conformers respectively).
• Optical rotations were measured at 20 0 C on a Perkin Elmer 341 polarimeter using 10 cm path length cells and are given in units of 10 'I degcm 2 g '1 . Samples were prepared in the solvent indicated at the concentration specified (measured in g/100 cm 3 ). NMR spectra were recorded on a Bruker AVANCE DRX400 ( 1 H, 400 MHz; 13 C, 100 MHz) or a
• Bruker AVANCE 300 ( 1 H, 300 MHz; 13 C, 75 MHz) spectrometer at ambient temperatures.
• 13 C NMR data chemical shifts are described in parts per million relative to CDCl 3 and are reported consecutively as position ( ⁇ c ), degree of hybridization as determined by DEPT experiments, and assignment.
• Acid 3 was shown to be an 77:23 trans:cis mixture of conformers by 1 H NMR analysis (the ratio was estimated from the integration of the signals at ⁇ 4.33-4.38 and 4.52-4.54, assigned to the Pro ⁇ -H of the major and minor conformers respectively): [ ⁇ ] D - 75.5 ( c 0.08 in MeOH); ⁇ H (300 MHz; CD 3 OD) 1.89-1.94 (0.77H, m, Pro ⁇ -H A H B ), 2.08-2.14 (IH, m, Pro ⁇ -H A H ⁇ ), 2.14-2.16 * (0.23 ⁇ , m, Pro ⁇ -H A H B ), 3.17- 3.20 (IH, m, Pro ⁇ -H A H B ), 3.53-3.57 (IH, m, Pro ⁇ -H A H*), 3.73-3.78 (IH 5 d, J 17.1, Gly ⁇ -H A H B ), 3.87-3.93 (IH, d, J 17.1, Gly ⁇ -H A H B
• Acid 3 (0.70 g, 2.18 mmol), L-glutamic acid dibenzyl ester />-toluenesulphonate 4 (1.19 g, 2.40 mmol), 1-hydroxybenzotriazole hydrate (0.37 g, 2.40 mmol) and l-ethyl-3-(3- dimethylaminopropyl)carbodiimide hydrochloride (0.46 g, 2.40 mmol) were dissolved in dichloromethane (60 cm 3 ) under nitrogen and cooled to 0 °C. Triethylamine (0.60 cm 3 , 4.30 mmol) was added dropwise over a period of 5 min.
• Tripeptide 5 was shown to be an 91:9 trans :cis mixture of conformers by 1 H NMR analysis (the ratio was estimated from the integration of the broad signals at ⁇ 5.89 and 6.51, assigned to the GIy-NH of the major and minor conformers respectively): m.p.
• GHypE (0.20 g, 80 %) as a white solid.
• GHypE was shown to be an 80:20 transicis mixture of conformers by 13 C NMR analysis (the ratio was estimated from the integration of the signals at ⁇ 70.2 and 68.5, assigned to the Pro ⁇ -C of the major and minor conformers respectively): mp 158-160 0 C.
• L-Pyroglutamic acid was purchased from Acros Organics.
• L-Glutamic acid dibenzyl ester />-toluenesulphonate was purchased from Bachem.
• Tert- ⁇ uty ⁇ acetate was purchased from Lancaster Chemical Co.
• Bis(2- oxo-3 -oxazolidinyl)phosphinic chloride (97%) was purchased from Fluka.
• 10% Palladium on activated carbon was purchased from Aldrich Chemical Company.
• Ester 2 (0.61 g 3 3.30 mmol) was dissolved in tetrahydrofuran (20 cm 3 ) under nitrogen and cooled to -78°C . Lithium hexamethyldisilazide (1.06 M, 3.30 cm 3 , 3.50 mmol) was added dropwise over a period of 5 min. The solution was stirred for 15 min, then N-benzyloxycarbonyl- glycyl- ⁇ -hydroxysuccinimide 4 3 (DC89.52)(1.23 g, 4.01 mmol) in tetrahydrofuran (30 cm 3 ) was added and the solution stirred for 45 min. Water (50cm 3 ) was added and the reaction allowed to warm to room temperature.
• GPyroE.HC ⁇ was shown to be exclusively the trans conformer by l H and 13 C NMR analysis 5 : mp 42-44 0 C; [ ⁇ ] D - 57.3 ( c 0.09 in MeOH); ⁇ H (400 MHz; D 2 O) 2.07-2.14 (IH, m, Glu ⁇ -H A H B ), 2.20-2.25 (IH, m, Glu ⁇ -H A H B ), 2.30-2.34 (1 ⁇ , m, Pyro ⁇ -H A ⁇ B ), 2.60-2.65 (3H, m, Pyro ⁇ -H A H B and Glu ⁇ - ⁇ 2 ), 2.74-2.89 (2H, m, Pyro ⁇ -H 2 ), 4.48-4.59 (3H, Gly ⁇ -H 2 and Glu ⁇ -H) and 4.93-4.95 (IH, m, Pyro ⁇ -H); ⁇ c (75 MHz, D 2 O) 22.5 (CH 2 , Pyro ⁇ -C), 2
• Ester 4 was shown to be an 85:15 trans :cis mixture of conformers by 1 H ⁇ MR analysis (the ratio was estimated from the integration of the signals at ⁇ 4.21-4.30 and 4.37-4.47, assigned to the Pro ⁇ -H of the minor and major conformers respectively: [ ⁇ ] D -36.0 (c 0.13 in MeOH ); ⁇ H (300 MHz; CDCl 3 ) 1.81-2.07 (4 H, m, Pro ⁇ -H 2 and Pro ⁇ -H 2 ), 2.36 (0.85 H, dd, J 9.2 and 15.5, CH 4 Hi 3 CO 2 ), 2.47* (0.15 H, d, J 10.1, CH ⁇ H B CO 2 ), 2.60* (0.15 H, d, J 10.1, CH A H 5 CO 2 ), 2.92 (0.85 ⁇ , dd, J 9.2 and 15.5, C ⁇ A H S CO 2 ), 3.43-3.44 (2 ⁇ , m, Pro ⁇ - ⁇ 2 ), 3.66 (2.55 H, s, OCH 3
• Acid 5 was shown to be an 76:24 trans:cis mixture of conformers by 1 H NMR analysis (the ratio was estimated from the integration of the broad signals at ⁇ 5.97 and 6.10, assigned to the GIy-NH of the major and minor conformers respectively): [ ⁇ ] D -33.3 (c 0.03 in MeOH); ⁇ H (300 MHz; CDCl 3 ) 1.81-2.04 (4 H, m, Pro ⁇ -H 2 and Pro ⁇ -H 2 ), 2.38 (0.76 H, dd, J 8.9, 15.7, CH 4 H B CO 2 ), 2.45* (0.24 H, d, J 10.6, CH A R B CO 2 ), 2.58* (0.24 H, d, J 10.6, CH A H S CO 2 ), 2.92 (0.76 ⁇ , dd, J 3.8 and 15.7, C ⁇ A H B CO 2 ), 3.36-3.47 (2 ⁇ , m, Pro ⁇ - ⁇ 2 ), 3.92 (1.52 H, m, GIyO-H 2 ), 3.
• Glycyl-L-Homoproyl-L-glutamic Acid fGHomoPE 62 A mixture of protected tripeptide 7 (0.39 g, 0.61 mmol) and 10 wt. % palladium on activated carbon (0.007 g, 0.07 mmol) in 10 % water/methanol (40 cm 3 ) was stirred under an atmosphere of hydrogen at room temperature for 20 h. The solution was filtered through a CeliteTM pad, washed with methanol ( 2 x 30 cm 3 ) and the filtrate evaporated to dryness to give a clear gum.
• GHomoPE (0.19 g, 93%) as a white solid.
• GHomoPE was shown to be an 80:20 trans:cis mixture of conformers by 1 H NMR analysis (the ratio was estimated from the integration of the signals at b 4.08 and 4.11, assigned to the Glu ⁇ -H of the major and minor conformers respectively: mp 48-50 0 C; [ce] D -36.6 (c 0.06 in H 2 O); ⁇ H (400 MHz; D 2 O) 1.84-2.22 (6 H, m, Glu ⁇ -H 2 , Pro ⁇ -H 2 and Pro- ⁇ H 2 ), 2.41-2.62 (3.2 H, m, Glu ⁇ -H 2 , CH 4 Hi 3 CO 2 and 2 x *CH 2 CO 2 ), 2.77 (0.8 ⁇ , dd, J 5.4 and 13.9, C ⁇ A H S CO 2 ), 3.45-3.55 (1 ⁇ , m, Pro
• L-3,4-Dehydroproline 1 was purchased from Fluka.
• L-Glutamic acid di-ter/-butyl ester hydrochloride 4 was purchased from Bachem.
• 3,4-Dehydroproline 1 (0.011 g, 0.097 mmol) and sodium hydrogen carbonate (0.0082 g, 0.097 mmol) were dissolved in water (1 cm 3 ).
• the reaction mixture was diluted with water, acidified with solid citric acid and extracted with dichloromethane (3 x).
• the combined organic layers were dried (MgSC ⁇ ), filtered and the solvent removed to afford crude acid 3 (0.0242 g, ca. 100%) that was used without further purification.
• Acid 3 was shown to be a 75:25 trans :cis mixture of conformers by 1 H NMR analysis (the ratio was estimated from the integration of the Pro ⁇ protons at ⁇ 5.21 and 5.13 of the major and minor conformers respectively): ⁇ n (300 MHz; CDCl 3 ; Me 4 Si) 1.41 1 [2.25H, s, C(CHs) 3 ], 1.42 [6.75H, s, C(CHa) 3 ], 3.83-4.08 (2 ⁇ , m, GIyO-H 2 ), 4.25-4.45 (2H, m, Pro ⁇ -H 2 ), 5.13 * (0.25H, br d, J 2.8, Pro ⁇ -H), 5.21 (0.75H, br d, /3.1, Pro ⁇ -H), 5.55-5.80 (2H, br m, 0-H and N-H) and 5.86-6.02 (2H, m, Pro ⁇ -H and Pro ⁇ -H).
• Triethylamine (0.041 cm 3 , 0.291 mmol) was added to a solution of acid 3 (0.0242 g, ca. 0.097 mmol), L-glutamic acid di-tert-butyl ester hydrochloride 4 (0.029 g, 0.097 mmol) and benzotriazol-l-yloxytris(dimethylamino)phos ⁇ honium hexafluorophosphate (BoP) (0.043 g, 0.097 mmol) in dichloromethane (3 cm 3 ).
• G- dehydroPE was shown to be a 84:16 trans:cis mixture of conformers by 1 H NMR analysis (the ratio was estimated from the integration of the Gly ⁇ protons at ⁇ 4.07 and 3.78 of the major and minor conformers respectively): no mp due to hygroscopic sample; [ ⁇ ]o -139.5 (c 0.2 in MeOH); 4 (300 MHz; D 2 O) 2.02-2.14 (IH, m, Glu ⁇ -H ⁇ H B ), 2.25-2.61 (IH 5 m, Glu ⁇ -H A H B ), 2.53-2.61 (2 ⁇ , m, Glu ⁇ -H 2 ), 3.78 * (0.16H, d, / 16.2 Gly ⁇ -H), 4.03 * (0.16H, d, / 16.5 Gly ⁇ -H), 4.07 (1.68H, s, Gly ⁇ -H 2 ), 4.38-4.45 (IH, m, Glu ⁇ -H), 4.53 (IH , dd, / 9.
• Example 6 Synthesis of analog 64 (Aminoisobutryl-L-prolyl-L-glutamic acid (AibPE)) General experimental details were as described in Example 2 above.
• N-Benzyloxycarbonyl aminoisobutyric Acid 1>2 1 Aminoisobutyric acid (2.00 g, 19.40 mmol) and sodium carbonate (6.16 g, 58.12 mmol) were dissolved in water (70 cm 3 ) and the solution cooled to 0 0 C. Benzylchloroformate (3.05 cm 3 , 21.4 mmol) in dioxane (20 cm 3 ) was added dropwise over a period of 15 min. The solution was stirred at 0 0 C for 1.5 h and warmed to room temperature.
• Amine 3 2 (DC64.10) (1.00 g, 2.36 mmol), acid 1 (0.56 g, 2.36 mmol) and 1- hydroxybenzotriazole hydrate (0.36 g, 2.26 mmol) were dissolved in tetrahydrofuran (10 cm 3 ) at room temperature. l-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (0.45 g, 2.36 mmol) was added and the solution stirred for 3 days.
• AibPE (0.14 g, 63%) as a light yellow solid.
• AibPE was shown to be an 65:35 trans: cis mixture of conformers by 1 H NMR analysis: mp 190-192 0 C : [ ⁇ fo -35.5 (c 0.06 in MeOH ): ⁇ H ( 200 MHz; D 2 O) 1.47* ( 1.05H, s, CH 3 ), 1.49* ( 1.05H, s, CH 3 ), 1.73 ( 1.95H, s, CH 3 ), 1.76 ( 1.95H, s, CH 3 ), 1.96-2.34 (6H, m, Pro/3-H 2 , Pro ⁇ -H 2 and GIu 1 S-H 2 ), 2.54-2.60 ( 1.3H, m, GIu 1 S-H 2 ) 2.60-2.64* ( 0.7H, m, GlUjS-H
• L-Norvaline 1 was purchased from Sigma.
• N-Benzyloxycarhonyl-gfycyl-L-prolyl-L-norvaline benzyl ester 4 To a stirred solution of ben2yl N-benzyloxycarbonyl-glycyl-L-proline 3 (0.4 g, 1.3 mmol) under nitrogen in dry dichloromethane (20 cm 3 ) was added diisopropylethylamine (0.31 cm 3 , 1.76 mmol). The suspension was stirred for 5 min (a solution was obtained), cooled to 0 0 C and ethyl chloroformate (0.166 cm 3 , 1.73 mol) was added.
• Tripeptide 4 was shown to be a 84:16 trans :cis mixture of conformers by 13 C ⁇ MR analysis (the ratio was estimated from the integration of the ⁇ E ⁇ -C carbons at ⁇ 34.0 and 33.6 and the E ⁇ -C carbons at ⁇ 18.5 and 18.8 of the major and minor conformers respectively): [ ⁇ ] D -70.3 (c 0.8 in dichloromethane); 4 (300 MHz; CDCl 3 ; Me 4 Si) 0.87 (3H, d, J 6.0, Ey-CH 3 ), 1.26-1.33 (2H, m, Ey-H 2 ), 1.58-1.68 (IH, m, Ep-H ⁇ H B ), 1.70-2.26 (5H, m, E ⁇ -H A H B , Pro ⁇ - ⁇ 2 , and Pro ⁇ -H 2 ), 3.38 (0.84H, d, J 7.6, Pro ⁇ -H ⁇ H B ), 3.51-3.56 (0.84H 5 m 5 Pro ⁇ -H A Hs) ; 3.
• Tripeptide 4 (0.308 g, 0.62 mmol) was dissolved in methanol (30 cm 3 ). The reaction flask was flushed with nitrogen and 10 wt. % palladium on activated carbon (66 mg, 0.062 mmol) was added and the mixture was hydrogenated at 1 atmosphere of hydrogen. After 30 min a white solid precipitated. Water (15 cm 3 ) was added to dissolve the solid and the reaction was stirred for 18 h. The reaction was filtered through Celite,TM washed with methanol/water and the solvent removed to yield an oil which was contaminated with palladium. The filtration was repeated again and the solvent removed to yield a white sold which was suspended in methanol and placed in a freezer overnight.
• GPNorval was shown to be a 78:22 transrcis mixture of conformers by 13 C NMR analysis (the ratio was estimated from the integration of the Pro ⁇ -C carbons at ⁇ 29.4 and 31.6 and the Pro ⁇ -C carbons at ⁇ 24.1 and 21.9 of the major and minor conformers respectively): [ ⁇ ] D -79 (c 0.1 in water); ⁇ H (300 MHz; D 2 O) 0.85 (3H, d, J 7.4, Ey- CH 3 ), 1.29 (2H, sextet, J 7.0, Ey-H 2 ), 1.53-1.75 (2H, m, E ⁇ -H 2 ) 1.88-2.05 (3H, m, Pro ⁇ -H A H B , Pro ⁇ -H 2 ) 2.09-2.27 (IH, m, Pro ⁇ -H A H B ) 5 3.51-3.82
• Example 8 Synthesis of analog 66 (Glycyl-D ⁇ L-pipecoiinyl-L-glutamic Acid (G(D 5 L)PIpE)) General experimental details were as described in Example 1 above. N-
• Benzyloxycarbonyl-glycine 1 N-hydroxysuccinimide 2 (97%) ( ⁇ HS), D,L-pi ⁇ ecolinic acid 4 (98%) and 10% palladium on activated carbon were purchased from Aldrich Chemical Company.
• N,N'-Dicyclohexylcarbodimide (DCC) was purchased from Riedel-de-Haen.
• L-glutamic acid dibenzyl ester p-toluenesulphonate 6 was purchased from Bachem.
• Bis(2-oxo-3- oxazolidinyl)phosphinic chloride (97%) (BoPCl) was purchased from Fluka.
• N-Benzyloxycarbonyl-glycine 1 7.50 g, 35.9 mmol
• N-hydroxysuccinimide 2 4.13 g, 35.9 mmol
• 1,2-dimethoxyethane 60 cm 3
• N,N'-Dicyclohexylcarbodimide 8.14 g, 39.5 mmol
• the solution was filtered and evaporated under reduced pressure to form a yellow oil.
• D,L-Pipecolinic acid 4 (0.20 g, 1.55 mmol) and N -benzyloxycarbonyl-glycyl ⁇ - hydroxysuccinimide 3 (0.47 g, 1.5 mmol) were added to dimethylformamide (2 cm 3 ) at room temperature under nitrogen. Triethylamine (0.22 cm 3 , 1.58 mmol) was then added dropwise over a period of 5 min. The solution was heated at 80 °C for 4 h and then cooled to room temperature and stirred for 2 days.
• Acid 5 was shown to be an 75:25 trans: cis mixture of conformers by 1 H ⁇ MR analysis (the ratio was estimated from the integration of the doublets at ⁇ 3.76 and 3.81, assigned to the Gly ⁇ -H A H ⁇ of the minor and major conformers respectively): b H (300 MHz; CD 3 OD) 1.05- 1.76 (5H, m, pi ⁇ -H, pip ⁇ -H 2 and pip ⁇ -H 2 ), 2.19 (0.75H, t, J 12.6, pip ⁇ -H), 2.62 * (0.25H, t, J 15.4, pip ⁇ -H), 3.14-3.25 (IH, m, pip ⁇ -H A H B ), 3.65-3.70 (IH, pip ⁇ -H A H B ), 3.76 * (0.25 ⁇ , d, J 16.7, Gly ⁇ - H A H B ), 3.81 (0.75H 5 d, J 16.9, Gly ⁇ -H A H B) ), 4.06 * (0.25H, d,
• Tripeptide 7 was shown to be an 87:13 trans: cis mixture of conformers of the two equimolar diasteoisomers by 1 H NMR analysis (the ratio was estimated from the integration of the signals at ⁇ 4.05-4.11 and 4.20-4.30, assigned to the Gly ⁇ -H 2 protons of the major and minor conformers respectively) : [ ⁇ ] D - 9.2 ( c 0.07 in MeOH) ; b H (300 MHz; CDCl 3 ; Me 4 Si ) 1.11-2.22 (8H, m, pip ⁇ -H 2 , pip ⁇ -H 2 pip ⁇ -H 2 and Glu ⁇ -H 2 ), 2.30-2.41 (2H, m, GlUy-H 2 ), 3.00-3.20 (1 H, m, pip ⁇ -H), 3.48 (1 H, t, J 10.6, pip ⁇ -H), 4.05-4.11 (1.74 H, m, Gly ⁇ -H 2 ), 4.20-4.30 * (0.26 H,
• G(D,L)PipE (0.34 g, 95%) as a white solid.
• G(D,L)PipE was shown to be an 80 : 20 trans:cis mixture of conformers of the two equimolar diastereomers by 1 H NMR analysis (the ratio was estimated from the integration of the triplets at ⁇ 2.91 and 3.34, assigned to the pip ⁇ -H A H B of the minor and major conformers respectively): mp 67-69 0 C.
• DC68 (Pyrrolidino GPE), respectively.
• Glutamic acid dibenzyl ester /»-toluenesulphonate (5) and bis(2-oxo-3-oxazolidinyl)phosphinic chloride (BoPCl, 97%) were purchased from Bachem and
• Glu ⁇ -C 53.9 (CH 2 , Pyr ⁇ -C), 57.9 (CH 2 , NCH 2 CO), 65.9 (CH 2 , OCH 2 Ph), 66.6 (CH 2 , OCH 2 Ph),
• Example 10 In Vitro Activity Studies of GPE Analogs The synthesized analogs of GPE were subjected to in vitro evaluation of their efficacy in prevention of neuronal cell death.
• Tissue underwent 15 trituration steps using a PlOOO pipettor to obtain dissociated cells, which were centrifuged for 5min at 250 G (4 0 C) and the supernatant was discarded.
• Cells were re-suspended into ImL DMEM/F-12 medium and were kept on ice.
• Cell suspension (400,000cells/cm2) was applied to O.lmg/mL poly-L-lysine pre-coated 96-well plates ( 3 h at 37 0 C) and the volume was increased up to lOO ⁇ L with DMEM/F-12 + 5% FBS.
• Cells were cultivated at 37 0 C in 100% humidity in a 5% CO2 atmosphere. After 24h the medium was changed to serum-free Neurobasal/B27. Cell medium was changed every 3 days and maintained until 8 days in vitro
• the injury paradigm involved 3OnM okadaic acid treatment with simultaneous administration of a GPE analog of this invention for 24h. i ⁇ L of 3 ⁇ M okadaic acid stock solution together with l ⁇ L of GPE analog dissolved in PBS (vehicle received 2 ⁇ L of PBS) were incubated for 24h with the striatal cells. Subsequently, 20 ⁇ L MTT (5mg/mL in PBS) was added for 4h. The reaction was terminated by addition of lOO ⁇ L 4% sodium dodecyl sulfate (SDS) solution. After 16-24h incubation time, photometric extinction values are read at 595nm. The difference between the vehicle and the okadaic acid injury condition was calculated. This value was set as the theoretical 100% recovery value. Measured values for the tested compounds were expressed in percentage of the 100% value. The unpaired Student's t-test was used for statistical analysis.
• the second centrifugation step was done with ImI of START V medium.
• the microexplants were reconstituted into 500 ⁇ l of START V medium and put on ice.
• Embryonic E 18/ 19 wistar rats were used for the generation of dissociated cortical cell cultures.
• the rear portion (occipital cortex - area 17/18 of the visual cortex) of the cortical plate is used for the generation of the cultures.
• Cells were grown for 3-1 ODIV in one part of serum-free medium and one part of rat cortex-derived cultivated astrocytic-conditioned medium (ACM).
• 96-well tissue culture plates were coated with 0.2mg/ml poly-L-lysine followed by 2 ⁇ g/ml laminin. Subsequently 60 ⁇ l of ACM were added per well and plate was stored at 37 0 C until plating of cortical cells.
• DMEM fetal calf serum
• the cell solution was extended with DMEM to 50ml of volume. The solution was then centrifuged for 5mins at 35Og at RT. The cells were resuspended in 40ml of DMEM + 10% FBS. The cells were tehn reconstituted into a 75cm 2 cell flask and incubated at 37°C/10% CO 2 /100% humidity in the presence of 5nM okadaic acid. This toxin killed neurons to enrich the astrocytic entity in the culture. The medium was replaced after 1 day with fresh DMEM + 10% FBS. The cell growth was monitored and media + FBS replaced twice weekly until the cells were confluent ( ⁇ 10-14 days).
• the cells were washed once with 20ml sterile PBS. Cells were incubated for 3 days in 30ml Neurobasal medium + B27 supplement to maintain cells under serum-free conditions. Cell supernatant was then filter through a 0.22 ⁇ m sterile filter and frozen in aliquots at -8O 0 C.
• the pellet was collected, washed (centrifugation) twice in NB/B27 medium (Invitrogen) and resuspended in 1 ml NB/B27 medium.
• Tissue was transferred into a petri dish and triturated twice with a glass pasteur pipette attached to a pipette to break up large pieces of tissue.
• the tissue was then triturated twice using a ImI syringe and 22gauge needl and passed through a lOO ⁇ m cell strainer to remove remaining large tissue pieces.
• the cells were washed with ImI NB/B27.
• the number of viable neurons was counted and the percentage of cell viability determined. We diluted the cell solution to the extent that the final cell count is 50,000 cells per 60 ⁇ l (833,333 cells/ml).
• the cortical cells were incubated at 37°C/10% CO 2 /100% humidity.
• phosphatase 1/2A antagonist okadaic acid is added for 24hrs. Simultaneously, an analog of GPE of this invention was administered. After 24hrs metabolic acitivity was measured by addition of MTT for 2-4hrs followed by addition of SDS- solution and photometric end point measurement at 595nm.
• Student's unpaired t-test is used for testing for statistical significance when comparing uninjured controls with the injured neuronal rescue agent containing conditions.
• Figure 1 also shows that GPE treatment (hatched bars) reversed the okadaic acid induced loss of cell viability.
• analog 49 Glycyl-L-thia-S.S-dimethylprolyl-L-glutamic acid
• Analog 49 protected the cells from okadaic acid-induced loss of cell viability in a concentration-dependent fashion. In the concentration range from 1OnM to lO ⁇ M, treatment with analog 49 produced 100% protection against loss of neural cell viability casued by okadaic acid.
• Figure 2 shows that as with analog 49, analog 50 (Glycyl-(D,L)-5,5-dimethylprolyl-L- glutamic acid) is also neuroprotective ( Figure 2).
• concentration range from 1OnM to 10OnM treatment with analog 50 produced 100% protection from loss of neural cell viability caused by okadaic acid.
• FIG. 3 shows that treatment with analog 60 (Glycyl-trans-4-hydroxy-L-prolyl-L-glutamic acid) is also neuroprorotective, with the statistically significant effects observed at concentrations of 10OnM and lOO ⁇ M and ImM.
• Figure 4 shows that analog 64 (Aminoisobutryl-L-prolyl-L-glutamic acid) AibPe is neuroprotective. In a concentration range from lOOuM to ImM, analog 64 was more effective than GPE. At a concentration of ImM, treatment with analog 64 produced complete protection from the loss of neural cell viability indued by okadaic acid.
• Figure 5 shows that analog 65 (Glycyl-L-prolyl-L-Norvaline) is neuroprotective over a broad range of concentrations, from 10 nM to 1 mM. At nearly every concentration tested, the cells treated with analog 65 showed 100% protection against loss of cell viability induced by okadaic acid.
• analog 65 Glycyl-L-prolyl-L-Norvaline
• Figure 6 shows that analog 66 (Glycyl-D ⁇ -pipecolinyl-L-glutamic Acid) is neuroprotective, with statistically significant effects observed at concentrations of 100 nM, 100 mM and 1 mM.
• Figure 7 shows that analog 67 (Pyrrolidinoglycyl-L-2-Methyl- ⁇ roline-L-Glutamic Acid) protected cerebellar cells from loss of neurites caused by okadaic acid. Statistically significant effects were observed at concentrations of 10 pM - 10 nM.
• okadaic acid toxicity produces histological changes similar to those produced by other causes of neural injury, including hypoxia/ischemia, stroke, Parkinson's disease and the like.
• this sytem for studying neural cell protection is predictive of effects that will be observed using other types of neurodegenerative stimuli.
• the neuroprotective effects observed in these studies are therefore highly likely to correlate with other systems for studying neuroprotection, including in vivo studies in experimental animals such as rats.
• compounds related to GPE have been show to protect animals in vivo against loss of neurons and functional neurological deficits associated by a variety of different conditions, we conclude from these studies, that GPE analogs of this invention can be useful in treating a variety of conditions associated with neurological deficits and neurological diseases.

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