AU1907292A

AU1907292A - Alpha-substituted polypeptides having therapeutic activity

Info

Publication number: AU1907292A
Application number: AU19072/92A
Authority: AU
Inventors: David Christopher Horwell; William Howson; John Hughes; Reginald Stewart Richardson
Original assignee: Warner Lambert Co LLC
Current assignee: Warner Lambert Co LLC
Priority date: 1991-04-24
Filing date: 1992-04-15
Publication date: 1992-12-21
Also published as: EP0668770A4; IE921321A1; PT100422A; EP0668770A1; CA2106764A1; WO1992019254A1; NZ242441A; JPH06507402A

Description

α-SUBSTITUTED POLYPEPTIDES

HAVING THERAPEUTIC ACTIVITY

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part application of United States Serial Number

07/690,755, filed April 24, 1991.

BACKGROUND OF THE INVENTION

Peptides form the main messenger systems within and between cells and they number more than a

thousand. Over a hundred peptides are known to act as hormone, neurohormones, or neurotransmitters, and this number is growing rapidly. The potential for drug development is therefore vast. However, the great majority of peptide messengers are not suitable for use as pharmaceuticals in their natural state.

The problems of natural peptides as drugs are lack of oral activity, failure to penetrate the blood-brain barrier, rapidly metabolized, no

selectivity for receptor subclasses, antigenic properties, and expensive to make.

The vast majority of small peptide messengers are not suitable as drugs, particularly where an orally administered and possibly centrally active drug is required. In this situation the development of modified peptides offer significant opportunities. The α,α-disubstituted amino acids are non-genetically coded synthetic analogues of natural mammalian α-amino acids and are incorporated at least once into the neuropeptides of this patent. Some examples of therapeutic applications of these modified peptides (peptoids) are given in Table I below.

TABLE I

Endogenous Peptide Peptoid

Type* Therapy

Angiotensin ANT Hypertension

Heart Failure

Atrial Natriuretic Factor AG Heart Failure

Thyrotropin Releasing AG Stroke

Factor Cognition

Spasticity Depression

Neuropeptide-Y ANT Hypertension

Depression

Obesity

Glucagon ANT Diabetes

Insulin AG Diabetes

Gastrin ANT Gastric Ulcer

Cancer

Bombesin ANT Cancer

Tachykinins ANT Antipsychotic SP, NKA, NKB Analgesic

Antiinflammatory Antiasthmatic

* ANT = Antagonist; AG = Agonist

These offer completely novel approaches to drug treatment. For example, all of the major

tranquilizers block central dopaminergic function indiscriminately. An antipsychotic modified peptide designed to act through the mesolimbic

CCK-neuropeptide/Dopamine system may be considerably more selective. An improvement in quality through the ability to modify drug resistant characteristics is also expected. In psychosis the blunting of affect leading to general impoverishment of social interactions with schizophrenics is expected to be susceptible to alternate modified peptide therapies. The highly selective behavioral responses elicited by individual neuropeptides is shown in the Table II below.

TABLE II

Behavioral Responses to Peptides

Peptide Behavior

Angiotensin-II Dipsogenesis

Cholecystokinin Cessation of

Feeding

Drowsiness

Enhanced Memory

Adrenocorticotrophic Hormone Enhanced Alertness

Enhanced Cognition ß-Endorphin Decreased Awareness

Amnesia

Reward

Analgesia

Dynorphin Decreased Reward

Drowsiness

Analgesia

Luteinizing Hormone Releasing Increased Sexual Factor Receptivity

Corticotrophin Releasing Anxiety

Factor Enhanced Vigilance

Thyrotropin Releasing Factor Increased Activity

Enhanced Awareness

SP or NKA A dopamine

behavioral

syndrome, i.e., increased

locomotion, rearing

SP Antidipsogenic

activity SUMMARY OF THE INVENTION

The invention relates to novel compounds of formula

and the pharmaceutically acceptable salts thereof wherein R ¹, R², R³, and R⁴ are as defined

hereinbelow.

In commonly assigned copending application

07/609,754, filed on April 24, 1991, by Horwell, et al, the disclosure of which is incorporated by reference, CCK analogues containing α,α-disubstituted amino acids are disclosed.

The invention also relates to a pharmaceutical composition containing an effective amount of a compound according to formula I in combination with a pharmaceutically acceptable carrier in unit dosage form for appetite suppression. The invention also relates to a method for suppressing appetite in a mammal.

The compounds of the invention are also useful for blocking the reaction caused by withdrawal from drug or alcohol use. The compounds of the invention are also useful in reducing gastric acid secretion, in treating gastrointestinal ulcers, in treating pain, treating and/or preventing stroke, treating inflammation, and in treating anxiety.

The compounds of the invention are also useful in treating cognitive deficits, small cell lung cancer, colonic cancer, peptic ulcers, and are useful in contraception. The invention also relates to a pharmaceutical composition for reducing gastric acid secretion containing an effective amount of a compound of formula I in combination with a pharmaceutically acceptable carrier in unit dosage form effective for reducing gastric acid secretion.

The invention also relates to a method for reducing gastric acid secretion in mammals which comprises administering an amount effective for gastric acid secretion reduction of the composition described above to a mammal in need of such

treatment.

The invention also relates to a pharmaceutical composition containing an effective amount of a compound of formula I in combination with a

pharmaceutically acceptable carrier in unit dosage form effective for reducing anxiety.

The invention also relates to a method for reducing anxiety in mammals which comprises

administering an amount effective for anxiety reduction of the composition described above to a mammal in need of such treatment.

pharmaceutically acceptable carrier in unit dosage form effective for treating gastrointestinal ulcers.

The invention further relates to a method for treating gastrointestinal ulcers in mammals which comprises administering an amount effective for gastrointestinal ulcer treatment of the composition as described above to a mammal in need of such treatment.

pharmaceutically acceptable carrier in unit dosage form effective for treating inflammation.

The invention further relates to a method for treating inflammation in mammals which comprises administering an amount effective of a composition as described above to a mammal in need of such

treatment.

The invention also relates to a pharmaceutical composition for preventing the withdrawal response produced by chronic treatment or abuse of drugs or alcohol.

The invention further relates to a method for treating the withdrawal response produced by

withdrawal from chronic treatment or withdrawal from abuse of drugs or alcohol. Such drugs include benzodiazepines, especially diazepam, cocaine, caffeine, opioids, alcohol, and nicotine. Withdrawal symptoms are treated by administration of an

effective withdrawal treating amount of a compound of the instant invention.

This invention also relates to a pharmaceutical composition containing a therapeutically effective amount of a compound according to formula I in combination with a pharmaceutically acceptable carrier in unit dosage form for treating psychosis.

The invention also relates to a method for treating psychosis in mammals which comprises

administering an amount effective for treatment of the composition described above to a mammal in need of such treatment.

This invention also relates to a pharmaceutical composition containing a therapeutically effective amount of a compound according to formula I in combination with a pharmaceutically acceptable carrier in unit dosage form for treating asthma.

The invention also relates to a method for treating asthma in mammals which comprises

This invention also relates to a pharmaceutical composition containing a therapeutically effective amount of a compound according to formula I in combination with a pharmaceutically acceptable carrier in unit dosage form for treating bladder dysfunction.

The invention also relates to a method for treating bladder dysfunction in mammals which

comprises administering an amount effective for treatment of the composition described above to a mammal in need of such treatment.

This invention also relates to a pharmaceutical composition containing a therapeutically effective amount of a compound according to formula I in combination with a pharmaceutically acceptable carrier in unit dosage form for treating arthritis and/or inflammatory pain.

The invention also relates to a method for treating arthritis and/or inflammatory pain in mammals which comprises administering an amount effective for treatment of the composition described above to a mammal in need of such treatment.

The invention further relates to methods of treating hypertension, heart failure, stroke,

cognition, memory enhancement, spasticity,

depression, and diabetes.

The invention further provides processes for the preparation of compounds of formula I. The invention further provides novel

intermediates useful in the preparation of compounds of formula I and also provides processes for the preparation of the intermediates.

The invention also relates to a pharmaceutical composition for treating pain and to a method of using a compound of formula I for treating pain.

The invention also relates to a pharmaceutical composition for treating and/or preventing stroke and to a method of using a compound of formula I for treating and/or preventing stroke.

DETAILED DESCRIPTION The following provides a dictionary of the terms used in the description of the invention.

The term "N-terminal protecting" as used herein refers to those groups known to the art intended to protect the N-terminus of an amino acid or peptide or to protect an amino group against undesirable

reactions during a synthetic procedure or to prevent the attack of exopeptidases on the compounds or to increase the solubility of the compounds and

includes, but is not limited to, sulfonyl, acetyl, pivaloyl, t-butyloxycarbonyl (Boc), benzyloxycarbonyl (Cbz), benzoyl, or an L- or D-aminoacyl residue, which may itself be N-protected similarly.

The term "C-terminal protecting group" as used herein refers to those groups known to the art intended to protect the C-terminus of an amino acid or peptide, these include but are not limited to an amide, methyl ester, benzyl ester/ether, tert-butyl ester/ether. Other examples of side chains and protecting groups are those known in the art. Any of those could be used.

The compounds of the invention are represented by formula

and the pharmaceutically acceptable salts thereof, wherein

R ¹ is an N-terminal blocking group or from 0 to 4 amino acid residues or hydrogen;

R ² is a si.dechai.n of a genetically coded amino acid except glycine;

R ³ is a C-terminal blocking group or from 0 to

4 amino acid residues, or -OH, or ORⁿ where Rⁿ is straight or branched alkyl or

cycloalkyl of 1 to 6 carbon atoms;

R ⁴ is a sidecham of a genetically coded amino acid, except glycine, or

-HC=CH₂,

-C≡CH,

-CH₂-CH=CH₂,

-CH₂C≡CH,

-CH₂Ar,

-CH₂OR,

-CH₂OAr,

-(CH₂)_nCO₂R,

- (CH₂) _nNR⁵R⁶ wherein n is an integer of from

0 to 3, R is hydrogen or lower alkyl,

Ar is a mono- or polycyclic

unsubstituted or substituted carbo- or heterocyclic aromatic or hydroaromatic moiety;

neither R² nor R⁴ can be hydrogen;

R¹ plus R³ cannot be greater than 4 amino acid residues in total. Preferred compounds of the invention are those rmula I selected from:

Formyl-MeMet-Leu-Phe-Obzl,

Formyl-Met-MeLeu-Phe-OBzl,

Formyl-Met-Leu-MePhe-OBzl,

Ac-MeLeu-Leu-Arginal,

Ac-Leu-MeLeu-Arginal,

MeTyr-Arg,

Tyr-MeArg,

MeTyr-Pro-Phe-Pro-NH₂,

Tyr-MePro-Phe-Pro-NH₂,

Tyr-Pro-MePhe-Pro-NH₂,

Tyr-Pro-Phe-MePro-NH₂,

Me-Arg-Lys-Asp-Val-Tyr,

Arg-MeLys-Asp-Val-Tyr,

Arg-Lys-MeAsp-Val-Tyr,

Arg-Lys-Asp-MeVal-Tyr,

Arg-Lys-Asp-Val-MeTyr,

MeArg-Lys-Glu-Val-Tyr,

Arg-MeLys-Glu-Val-Tyr,

Arg-Lys-MeGlu-Val-Tyr,

Arg-Lys-Glu-MeVal-Tyr,

Arg-Lys-Glu-Val-MeTyr,

MeAsp-Leu-Asp-Pro-Arg,

Asp-MeLeu-Asp-Pro-Arg,

Asp-Leu-MeAsp-Pro-Arg,

Asp-Leu-Asp-MePro-Arg,

Asp-Leu-Asp-Pro-MeArg,

MeLys-Trp-Lys,

Lys-MeTrp-Lys,

Lys-Trp-MeLys,

MePhe-Met-Arg-Phe-NH₂,

Phe-MeMet-Arg-Phe-NH₂,

Phe-Met-MeArg-Phe-NH₂,

Phe-Met-Arg-MePhe-NH₂, MeGlp-His-Pro,

Glp-MeHis-Pro,

Glp-His-MePro,

MeArg-Tyr-Leu-Pro-Thr,

Arg-MeTyr-Leu-Pro-Thr,

Arg-Tyr-MeLeu-ProThr,

Arg-Tyr-Leu-MePro-Thr,

Arg-Tyr-Leu-Pro-MeThr,

MeThr-Lys-Pro-Arg,

Thr-MeLys-Pro-Arg,

Thr-Lys-MePro-Arg,

Thr-Lys-Pro-MeArg,

MeThr-Pro-Arg-Lys,

Thr-MePro-Arg-Lys,

Thr-Pro-MeArg-Lys,

Thr-Pro-Arg-MeLys,

MeThr-Val-Leu,

Thr-MeVal-Leu, and

Thr-Val-MeLeu.

More preferred compounds of the invention are those of formula I selected from:

Me-Tyr-Gly-Gly-Phe-Met,

MeTyr-Gly-Gly-Phe-Met-NH₂,

MeTyr-Gly-Gly-Phe-Leu-NH₂,

Tyr-Gly-Gly-MePhe-Met,

Tyr-Gly-Gly-MePhe-Met-NH₂,

Tyr-Gly-Gly-MePhe-Leu-NH₂,

Tyr-Gly-Gly-Phe-MeMet,

Tyr-Gly-Gly-Phe-MeMet-NH₂,

Tyr-Gly-Gly-Phe-MeLeu-NH₂,

Z-DMePhe-Phe-Gly,

Z-DPhe-MePhe-Gly,

MeArg-Pro-Tyr-Ile-Leu,

Arg-MePro-Tyr-Ile-Leu,

Arg-Pro-MeTyr-Ile-Leu, Arg-Pro-Tyr-Melle-Leu,

Arg-Pro-Tyr-Ile-MeLeu,

MeLeu-Asp-Ile-Ile-Trp,

Leu-MeAsp-Ile-Ile-Trp,

Leu-Asp-Melle-Ile-Trp,

Leu-Asp-Ile-Melle-Trp,

Leu-Asp-Ile-Ile-MeTrp,

MeGlu-Cys-Tyr-Phe,

Glu-MeCys-Val-Tyr-Phe,

Glu-Cys-MeVal-Tyr-Phe,

Glu-Cys-Val-MeTyr-Phe, and

Glu-Cys-Val-Tyr-MePhe.

Most preferred compounds of the invention are those of formula I selected from:

MeLys-Trp-Asp-Asn-Gln,

Lys-MeTrp-Asp-Asn-Gln,

Lys-Trp-MeAsp-Asn-Gln,

Lys-Trp-Asp-MeAsn-Gln,

Lys-Trp-Asp-Asn-MeGln,

MeVal-Gly-His-Leu-Met-NH₂,

Val-Gly-MeHis-Leu-Met-NH₂,

Val-Gly-His-MeLeu-Met-NH₂,

Val-Gly-His-Leu-MeMet-NH₂,

MeGlp-His-Trp-Ser-Tyr,

Glp-MeHis-Trp-Ser-Tyr,

Glp-His-MeTrp-Ser-Tyr,

Glp-His-Trp-MeSer-Tyr,

Glp-His-Trp-Ser-MeTyr,

Gly-MeLeu-Arg-Pro-Gly-NH₂,

Gly-Leu-MeArg-Pro-Gly-NH₂,

Gly-Leu-Arg-MePro-Gly-NH₂,

MeTyr-Pro-Ser-Lys-Pro,

Tyr-MePro-Ser-Lys-Pro,

Tyr-Pro-MeSer-Lys-Pro,

Tyr-Pro-Ser-MeLys-Pro, Tyr-Pro-Ser-Lys-MePro,

MeThr-Arg-Gln-Arg-Tyr-NH₂,

Thr-MeArg-Gln-Arg-Tyr-NH₂,

Thr-Arg-MeGln-Arg-Tyr-NH₂,

Thr-Arg-Gln-MeArg-Tyr-NH₂,

Thr-Arg-Gln-Arg-MeTyr-NH₂,

Gly-MeTrp-Thr-Leu-Asn,

Gly-Trp-MeThr-Leu-Asn,

Gly-Trp-Thr-MeLeu-Asn,

Gly-Trp-Thr-Leu-MeAsn,

MeLeu-Tyr-Gly-Leu-Ala-NH₂,

Leu-MeTyr-Gly-Leu-Ala-NH₂,

Leu-Tyr-Gly-MeLeu-Ala-NH₂,

Leu-Tyr-Gly-Leu-Aib-NH₂,

MePhe-Phe-Trp-Lys-Thr,

Phe-MePhe-Trp-Lys-Thr,

Phe-Phe-MeTrp-Lys-Thr,

Phe-Phe-Trp-MeLys-Thr,

Phe-Phe-Trp-Lys-MeThr,

MePhe-Phe-Gly-Leu-Met-NH₂,

Phe-MePhe-Gly-Leu-Met-NH₂,

Phe-Phe-Gly-MeLeu-Met-NH₂,

Phe-Phe-Gly-Leu-MeMet-NH₂,

and the N^α-4-hydroxyphenylacetyl derivatives and the NH₂-CO-(CH₂)₄-CO- derivatives of the above four compounds,

N-[[(4-Chlorophenyl)methoxy]carbonyl]-L-tryptophyl-α-methyl-DL-phenylalaninamide,

N-[[[4-(Trifluoromethyl)phenyl]methoxy]-carbonyl]-L-tryptophyl-α-methyl-DL-phenylalaninamide, N-[([1,1'-Biphenyl]-4-ylmethoxy)carbonyl]-L-trvptophyl-α-methyl-DL-phenylalaninamide,

N-[(9-Anthracenylmethoxy)carbonyl]-L-tryptophyl-α-methyl-DL-phenylalaninamide, N-[(1-Naphthalenylmethoxy)carbonyl]-L-tryptophyl-α-methyl-DL-phenylalaninamide,

N-[(1-Naphthalenylmethoxy)carbonyl]-L-tryptophyl-α-methyl-L-phenylalaninamide,

N-[(1-Naphthalenylmethoxy)carbonyl]-L-tryptophyl-α-methyl-D-phenylalaninamide,

N-[[[4-(Propoxycarbonyl)phenyl]-methoxy]carbonyl]-L-tryptophyl-α-methyl-DL- phenylalaninamide,

N-[(Phenylmethoxy)carbonyl]-L-tryptophyl-α-methyl-DL-phenylalanylglycinamide,

N-[(1-Naphthalenylmethoxy)carbonyl]-L-tryptophyl-α-methyl-DL-phenylalanylglycinamide,

N-[(1-Naphthalenylmethoxy)carbonyl]-L-tryptophyl-α-methyl-L-phenylalanylglycinamide, and

N-[[(2,3-Dimethoxyphenyl)methoxy]carbonyl]-L-tryptophyl-α-methyl-DL-phenylalaninamide.

The compounds include solvates, hydrates, and pharmaceutically acceptable salts of the compounds of formula I above.

The compounds of the present invention may exist as diastereomers, mixtures of diastereomers, or as the mixed or the individual optical enantiomers. The present invention contemplates all such forms of the compounds. The mixtures of diastereomers are

typically obtained as a result of the reactions described more fully below. Individual diastereomers may be separated from mixtures of the diastereomers by conventional techniques such as column

chromatography or repetitive recrystallizations.

Individual enantiomers may be separated by

conventional methods well known in the art such as conversion to a salt with an optically active

compound, followed by separation by chromatography or recrystallization and reconversion to the nonsalt form.

The compounds of the present invention may be formed by coupling individual substituted α-amino acids by methods well known in the art. (See, for example, standard synthetic methods discussed in the multi-volume treatise The Peptides, Analysis,

Synthesis, Biology, by Gross and Meienhofer, Academic Press, New York). If known, the individual

substituted alpha amino acid starting materials are synthesized by methods within the skill of the art. (Synthesized racemic [DL]-α-methyl tryptophan methyl ester - see Brana, M. F., et al, J. Heteroσyclic Chem., 1980.

In Scheme I below, the α-MePhe was N-terminally protected with (BOC)₂O to afford BOC α-MePhe. (1) Compound 1 was then activated with DCCI and HOBt and reacted with NH₃ (g) to give the amide. (2) Removal of the BOC group with TFA gave the amine (3), which was reacted with FMOC-L-TrpOPfp to afford the

dipeptide. (4) A further deprotection with piperidine in DMF gave the amine (5), which was reacted with the appropriate chloroformate to give the Examples 7 through 14. (6-13)

)

In Scheme 2 below, Compound 1 was activated with DCCI and HODhbt to give 14, which was reacted with CTlyNH₂ in EtOAc to afford the N-protected

dipeptide. (15) Removal of the BOC group with TFA gave the amine (16), which was reacted with ROCO(L) Trp activated with HBTU to give the Examples 18 and 19. (17,18)

2

(Examples 18 and 19)

For preparing pharmaceutical compositions from the compounds of this invention, inert,

pharmaceutically acceptable carriers can be either solid or liquid. Solid form preparations include powders, tablets, dispersible granules, capsules, cachets, and suppositories.

A solid carrier can be one or more substances which may also act as diluents, flavoring agents, solubilizers, lubricants, suspending agents, binders, or tablet disintegrating agents; it can also be an encapsulating material.

In powders, the carrier is a finely divided solid which is in a mixture with the finely divided active component. In tablets, the active component is mixed with the carrier having the necessary binding properties in suitable proportions and compacted in the shape and size desired.

For preparing suppository preparations, a low-melting wax such as a mixture of fatty acid glycerides and cocoa butter is first melted and the active ingredient is dispersed therein by, for example, stirring. The molten homogeneous mixture is then poured into convenient sized molds and allowed to cool and solidify.

The powders and tablets preferably contain 5% to about 70% of the active component. Suitable carriers are magnesium carbonate, magnesium stearate, talc, lactose, sugar, pectin, dextrin, starch, tragacanth, methyl cellulose, sodium carboxymethyl cellulose, a low-melting wax, cocoa butter, and the like.

The term "preparation" is intended to include the formulation of the active component with

encapsulating material as a carrier providing a capsule in which the active component (with or without other carriers) is surrounded by a carrier which is thus in association with it. Similarly, cachets are included.

Tablets, powders, cachets, and capsules can be used as solid dosage forms suitable for oral

administration.

Liquid form preparations include solutions, suspensions, and emulsions. Sterile water or

water-propylene glycol solutions of the active compounds may be mentioned as an example of liquid preparations suitable for parenteral administration. Liquid preparations can also be formulated in

solution in aqueous polyethylene glycol solution.

Aqueous solutions for oral administration can be prepared by dissolving the active component in water and adding suitable colorants, flavoring agents, stabilizers, and thickening agents as desired.

Aqueous suspensions for oral use can be made by dispersing the finely divided active component in water together with a viscous material such as natural synthetic gums, resins, methyl cellulose, sodium carboxymethyl cellulose, and other suspending agents known to the pharmaceutical formulation art.

Preferably the pharmaceutical preparation is in unit dosage form. In such form, the preparation is in unit dosage form. In such form, the preparation is divided into unit doses containing appropriate quantities of the active component. The unit dosage form can be a packaged preparation, the package containing discrete quantities of the preparation, for example, packeted tablets, capsules, and powders in vials or ampoules. The unit dosage form can also be a capsules, cachet, or tablet itself, or it can be the appropriate number of any of these packaged forms. Some of the peptides of the invention were constructed on solid-phase resins designed to produce C-terminal amides either by treatment of the resin with ammonia in methanol or by direct cleavage of an appropriately substituted resin using trifluoroacetic acid, with the required scavengers, giving the amides directly. The latter protocol was used with DuPont RapidAmide^® or Nova Biochem Ultrasyn C^® resins either in a simple bubbler apparatus (DuPont resin) or automated synthesizer (Nova Biochem resin).

Using a Pharmacia 4170 automated peptide

synthesizer and Bioplus^® software the peptides were constructed from the C-terminus using Fmoc amino acid pentafluorophenyl or DHBt esters and HOBt catalysis. Each residue was present in a fivefold excess to ensure rapid and complete acylation. On a 0.095 mmol scale the peptide was isolated following TFA cleavage (94% TFA, 5% anisole, 1% ethanedithiol) from the resin (2 hours, room temperature).

The two isomers were separated by RP-HPLC

(250 × 25 mm column, gradient elution, Solvent A 0.1% aqueous TFA, Solvent B 0.1% FFA in MeCN, gradient 20% to 80% B over 20 minutes. The peptides of the invention can be made by the above method. Although any compatible resin may be used or, alternatively, solution phase synthesis may be used.

Such peptides include but are not limited to the short chemotactic peptides, for example,

formyl-Met-Leu-Phe-OBz, Met-enkephalin,

enkephalinamides, leupeptin (Ac-Leu-Leu-Arginol), Kyotorphin (Tyr-Arg), Morphiceptin

(Tyr-Pro-Phe-Pro-NH₂), Thymopoetin II

(Arg-Lys-Asp-Val-Tyr) , Splenopentin

(Arg-Lys-Glu-Val-Tyr), Hamburger pentapeptide

(Asp-Leu-Asp-Pro-Arg), virus replication inhibiting peptide (Z-DPhe-Phe-Gly), DNA binding peptide

(Lys-Trp-Lys), Molluscan cardioexcitatory peptide (Phe-Met-Arg-Phe-NH₂ and all FMRF-amide analogues), TRH (pGlu-His-Pro), Proctolin (Arg-Tyr-Leu-Pro-Thr), Tuftsin, (Thr-Lys-Pro-Arg), Kentsin

(Thr-Pro-Arg-Lys), schizophrenia-related peptide (Tnr-Val-Leu) and short polypeptides or 5-residues or less which are fragments of longer peptides.

Preferred compounds are:

LTyr-Gly-Gly-a-MePhe-LLeu (isomer 1) and

LTyr-Gly-Gly-α-MePhe-LLeu (isomer 2) whose full chemical names are N-[α-methyl-N-[N-(N-L-tyrosylglycyl)glycyl]-L-phenylalanyl]-L-leucinetrifluoroacetate (1:1 salt) and N-[α-methyl-N-[N-(N-L-tyrosylglycyl)glycyl]-D-phenylalanyl]-L-leucine trifluoroacetate (1:1 salt).

Some of the compounds were evaluated in three tachykinin binding assays:

For the NK₁ receptor - measurement of the binding of [¹²⁵I]-Bolton Hunter labeled substance P

(0.1 nM) to guinea pig cerebral cortex membranes, and for the NK₃ receptor - measurement of the binding of [³H]-senktide (2 nM) to guinea pig cerebral cortex membranes. See Lee, C. M., et al, Eur. J. Pharmacol. 130:209 (1986), and Guard, S., et al, Brit. J.

Pharmacol. 99:767 (1990).

For the NK₂ receptor - measurement of the binding of [¹²⁵I]-iodohistidyl neurokinin A (0.1 nM) to hamster urinary bladder membranes. See Buck and Shatzer, Life Sci. 42:2701 (1988). The data in Table III show that the compounds are selective NK2 receptor ligands. The compounds of Examples 18 and 19 illustrate NK₂ receptor

antagonism. See Table IV. Therefore, they are expected to be useful in treating disorders mediated by tachykinins, e.g., respiratory disorders,

inflammation, gastrointestinal disorders, ophthalmic diseases, allergies, pain, circulatory insufficiency, diseases of the central nervous system, and migraine.

NK₂ Functional Data Summary

Tissue Agonist Antagonist Conc. Dose\

Ratio pKa

Rat Colon Eledoisin Example 18 1 μM 3.1 6.5

Example 19 1 μM 7.7 6.8

1.659,874 10 μM 10.3 7.0

Hamster Bladder

Urinary NKA Example 18 3 μM 30 7.0

Example 19 3 μM 29 6.9

L659,874 3 μM 29 6.9

Hamster Trachea NKA Example 18 1 μM 11 6.9

Example 18 3 μM 46 7.2

Example 19 3 μM 31 6.9

Example 19 10 μM 472 7.2

L659,874 1 μM 11 7.0

L659,874 3 μM 41 7.1 ^a L659, 874 is a standard NK₂ antagonist . Its

chemical name is Glycinamide, N-acetyl-L-leucyl- L-methionyl-L-glutaminyl-L-tryptophyl- L-phenylalanyl-Ac-LLeu-LMet-LGln-LTrp-LPhe-Gly-NH₂

For the hamster trachea, see Maggi , C. A. ,

Patacchini, R. , Rovero, P . , and Meri, A. Eur . J .

Pharmacol . , 1989; 166 : 435-440.

For the hamster urinary bladder, see

Mizrahi, J. , Dion, S . , D' Orleans-Juste, P . ,

Escher, B . , Drapeau, G. , and Regoli, D . , Eur. J.

Pharmacol . , 1985; 118 : 25-36. For the rat colon, see Bailey, S. J. and

Jordan, C. C., Br. J. Pharmacol., 1984;82:441-451.

The following examples illustrate the instant invention but are not intended to limit it in any way.

EXAMPLE 1

Tyr-Gly-Gly-αMePhe-Leu

The peptide was prepared and separated as described above, using solid-phase methodology.

Isomer 1 (L,D,L or L,L,L), LTyr-Gly-Gly-αMePhe-LLeu NMR (D₂O) δ 0.89 (6H, br d), 1.41 (3H, s), 1.57 (3H, brm), 3.18 (2H, 2bq), 3.12 (2H, d), 3.92 (4H, m), 4.25 (2H, m), 6.88 (2H, d), 7.18 (4H, d), 7.46 (3H, m). FAB-MS 57C (M+H)⁺, 592 (M+Na)⁺, 608 (M+K)⁺.

Isomer 2 (L,L,L or L,D,L) LTyr-Gly-Gly-αMePhe-LLeu NMR (D₂O) δ 0.88 (6H, dd), 1.43 (3H, s), 1.57 (3H, br m), 3.20 (4H, m), 3.91 (4H, m), 4.23 (2H, m), 6.88 (2H, d), 7.16 (4H, d), 7.33 (3H, m). FAB-MS 570 (M+H)⁺, 592 (M+Na)⁺, 608 (M+K)⁺.

EXAMPLE 2

N-(t-Butyloxycarbonyl)-DL-α-methylphenylalanine (1) DL-α-Methylphenylalanine (5.0 g, 28 mmol) was dissolved in warm 10% Na₂CO₃ solution (60 mL) and then cooled to 0°C. t-Butyloxycarbonyl anhydride (6.39 g, 29.3 mmol) in dioxan (50 mL) was added dropwise and the mixture stirred at 0°C for 1 hour. The mixture was then allowed to warm to room

temperature and stirred for a further 24 hours. The solvents were then distilled off in vacuo and the residue taken up in H₂O. This was then washed with CH₂Cl₂ (3x), acidified with citric acid, and extracted with CH₂Cl₂ (3x). The organic extracts were combined, dried (MgSO₄), and the solvent

distilled off in vacuo to give 1 as a white solid (6.2 g, 25.1 mmol, 90%): ¹H NMR (DMSO-d₆) δ 1.18 (3H, s), 1.41 (9H, s), 2.91 (1H, d, J 13 Hz), 3.31 (1H, d, J 13 Hz), 6.71 (1H, bs), 7.09 (2H, d), 7.25 (3H m), 12.50 (1H, bs).

EXAMPLE 3

N-(t-Butyloxycarbonyl)-PL-α-methylphenylalaninamide ill

1 (6.7 g, 22 mmol) was dissolved in CH₂Cl₂

(80 mL) and 1,3-dicyclohexylcarbodiimide (4.9 g, 24 mmol) followed by 1-hydroxybenzotriazole

monohydrate (3.9 g, 28.8 mmol) added and the mixture stirred for 0.5 hour at room temperature. DMF

(15 mL) was then added, the solution cooled to -10°C and a slow stream of NH₃ (g) bubbled through. The mixture thickened almost immediately so a further amount of DMF (50 mL) was added. After 0.5 hour, the addition of NH₃ (g) was stopped and the white

precipitate removed by filtration and washed with EtOAc. The washings were combined with the filtrate and the solvent distilled off in vacuo. The residue was partitioned between H₂O (500 mL) and CH₂Cl₂. The aqueous layer was washed with CHCl₂ (3x), the organic extracts combined, washed with a saturated NaHCO₃ solution, dried (MgSO₄), and the solvent distilled off in vacuo. The white solid obtained was further purified by flash column chromatography on silica, eluting with a mixture of CHCl₃:MeOH (95:5) to give 2 as a white solid (4.4 g, 15.8 mmol, 66%): ¹H NMR (DMSO-d₆) δ 1.33 (3H, s), 1.41 (9H, s), 3.31 (2H, bs), 6.25 (1H, bs), 7.15 (6H, m), 7.41 (1H, bs). EXAMPLE 4

DL-α-Methylphenylalaninamide (3)

2 (4.4 g, 15 mmol) was stirred in TFA (15 mL) at room temperature for 15 minutes. The TFA was

distilled off in vacuo and the residue taken up in EtOAc. The organic solution was carefully washed with saturated NaHCO₃ solution, dried (MgSO₄), and the solvent removed in vacuo to give 3 as a white solid (1.9 g, 12.1 mmol, 70%) ¹H NMR (MeOH-d₄) δ 1.40 (3H, s), 2.77 (1H, d, J 13 Hz), 3.21 (1H, d,

J 13 Hz), 7.30 (5H, m).

EXAMPLE 5

N- (9H-Fluoren-9-ylmethoxy)carbonyl]-L-tryptophyl-DL-α-methylphenylalaninamide (4)

3 (1.8 g, 10.1 mmol) and N-[(9H-fluoren-9-ylmethoxy)carbonyl]-L-tryptophan pentafluorophenyl ester (6.0 g, 10.1 mmol) were stirred together in DMF

(50 mL) at room temperature for 18 hours. The solution was concentrated in vacuo and H₂O (400 mL) added. The aqueous suspension was extracted with EtOAc (3x) and the organic extracts combined, dried (MgSO₄) and the solvent removed in vacuo to give crude 4.

EXAMPLE 6

L-Tryptophyl-DL-α-methylphenylalaninamide (5)

4 (3.65 g, 6.2 mmol) was dissolved in a 20% solution of piperidine in DMF (20 mL) and stirred at room temperature for 20 minutes. The mixture was then concentrated in vacuo and H₂O (400 mL) added; the white precipitate formed was then removed by filtration. Citric acid was added to the filtrate to pH 3 and washed with EtOAc (3x). The aqueous layer was made alkaline (pH 9) with solid Na₂CO₃ and extracted with EtOAc (3x). The organic extracts were combined, dried (MgSO₄) and the solvent removed in vacuo to give 5 as a pale yellow solid (2.2 g). Purification by flash column chromatography on silica, eluting with CH₂Cl₂:MeOH (10:1) gave the product 5 as a white foam (1.8 g, 4.93 mmol, 80%): ¹H NMR (DMSO-d₆) δ 1.45 (0.5 × 3H, s), 1.51 (0.5 × 3H, s), 1.81 (2H, bs), 2.59 (0.5 × H, dd,

J 10.14 Hz), 2.76 (0.5 × H, dd, 9, 14 Hz), 3.15 (2H, m), 3.45 (2H, m) , 6.95-7.60 (12H, m), 8.16 (0.5 × H, s), 8.28 (0.5 × H, s), 10.85 (1H, s).

EXAMPLE 7

N-[[(4-Chlorophenyl)methoxy]carbonyl]-L-tryptophyl-α-methyl-DL-phenylalaninamide (6)

Pyridine (0.11 mL, 1.4 mmol) was added dropwise to a stirred solution of 4-chlorobenzyl alcohol

(0.20 g, 1.4 mmol) and triphosgene (0.15 g,

0.51 mmol) in CH₂Cl₂ (5 mL) at 0°C and stirred for 5 minutes. The solvent was removed in vacuo and the resulting oil triturated with Et₂O and filtered. The filtrate was added to a solution of 5 (0.26 g,

0.71 mmol) and triethylamine (0.10 mL, 0.71 mmol) in THF (25 mL) and stirred overnight. The solvent was removed in vacuo to give a white solid which was partitioned between EtOAc and 10% citric acid

solution. The organic layer was washed with

saturated NaHCO₃ solution and H₂O and dried (MgSO₄) . Further purification by flash column chromatography on silica eluting with a mixture of CH₂Cl₂:MeOH

(95:5) gave 6 as a white foam (0.23 g, 0.43 mmol, 61%); mp 89-101.3°C; MS (FAB) m/e 533 [M+H]: ¹H NMR (DMSO-d₆) 6 1.38 (0.5 × 3H, s, α-CH₃), 1.40

(0.5 × 3H, s, α-CH₃), 2.80-3.40 (4H, m, CH₂-indole, CH₂Ph), 4.10-4.32 (1H, m, Trp α-H), 4.80-4.99 (2H, m, CH₂O) , 6. 90-7 .78 (18H, m, Ar, CONH₂, CONH, OCONH) , 10.70 (1H, s, indole NH) ; Anal . (C₂₉H₂₉N₄O₄C· 0 .3 H₂O) C, H, N. EXAMPLE 8

N-[[[4-(Trifluoromethyl)phenyl]methoxy]carbonyl]- L-tryptophyl-α-methyl-DL-phenylalaninamide (7)

Prepared by the same method as 6. White foam (0.092 g, 62%); mp 91-112°C; MS (FAB) m/e 567 [M+H]; 1H NMR (DMSO-d₆) δ 1.38 (0.5 × 3H, s, α-CH₃), 1.41

(0 .5 × 3H, s, α-CH₃) , 2 . 70, 3.46 (4H, m, CH₂-indole, CH₂Ph) , 4.12-4.36 (1H, m, Trp α-H) , 4 . 90-5.16 (2H, m, CH₂O) , 6. 90-7 .88 (18H, m, Ar, CONH₂ CONH, OCONH) , 10.84 (1H, s, indole NH) ; Anal . (C₃₀H₂₉N₄O₄F₃.

0.75 H₂O) C, H, N.

EXAMPLE 9

N-[([1-1'-Biphenyl]-4-ylmethoxy)carbonyl]-L-tryptophyl-α-methyl-DL-phenylalaninamide (8)

Prepared by the same method as 6. White foam

(0.050 g, 32%); mp 92-102°C; MS (FAB) m/e 576 [M+H]; 1H NMR (DMSO-d₆) δ 1.38 (0.5 × 3H, s, α-CH₃), 1.39 (0.5 × 3H, s, α-CH₃), 2.72-3.40 (4H, m, CH₂-indole, CH₂Ph), 4.12-4.35 (1H, m, Trp α-H), 4.90-5.08 (2H, m, CH₂O), 6.92-7.85 (23H, m, Ar, CONH₂, CONH, OCONH),

10.90 (1H, s, indole NH); Anal. (C₃₅H₃₄N₄O₄· 0.75 H₂O) C, H, N.

EXAMPLE 10

N-F(9-Anthracenylmethoxy)carbonyl]-L-tryptophyl-α-methyl-DL-phenylalaninamide (9)

Prepared by the same method as 6. Yellow foam (0.10 g, 23%); mp 113-130°C; MS (FAB) m/e 599 [M+H] ; ¹H NMR (DMSO-d₆) 1.36 (3H, s, α-CH₃), 2.25-3.20 (2H, m, CH₂-indole), 3.25-3.40 (2H, m, CH₂Ph), 4.20-4.38 (1H, m, Trp α-H), 5.95 (0.5 × 2H, AB, J 12 Hz,

CH₂Ar), 6.01 (0.5 × 2H, AB, J 12 Hz, CH₂Ar), 6.85-7.20 (17H, m, Ar, CONH₂, OCONH), 7.77 (0.5 × H, s, CONH), 7.83 (0.5 × H, s, CONH), 8.10 (1H, s, Ar), 8.13 (1H, s, Ar), 8.28 (1H, s, Ar), 8.31 (1H, s, Ar), 8.67 (1H, s, Ar), 10.80 (1H, s, indole NH); Anal.

(C₃₇H₃₄N₄O₄·0.7 H₂O) C, H, N.

EXAMPLE 11

N-[(1-Naphthalenylmethoxy)carbonyl]-L-tryptophyl-α-methyl-DL-phenylalaninamide (10)

Prepared by the same method as 6. White foam (0.13 g, 34%); mp 102-113°C; MS (FAB) m/e 549 [M+H]; ¹H NMR (DMSO-d₆) δ 1.40 (3H, s), 2.87 (1H, m), 3.05- 3.45 (3H, m), 4.15-4.40 (1H, m), 5.30-5.50 (2H, m), 6.90-8.00 (21H, m), 10.70 (1H, s); Anal. (C₃₃H₃₂N₄O₄-0.4 H₂O) C, H, N.

EXAMPLE 12

N-[(1-Naphthalenylmethoxy)carbonyl]-L-tryptophyl-α-methyl-L-phenylalaninamide (11)

Prepared by the same method as 6, -α-methyl-L-phenylalanine was obtained by the method of Turk, et al (Turk, J., Panse, G. T., Marshall G. R., J.

Org. Chem. 40:953 (1975)).

EXAMPLE 13

N-[(1-Naphthalenylmethoxy)carbonyl]-L-tryptophyl-α-methyl-D-phenylalaninamide (12)

Prepared by the same method as 6. D-α-methyl-phenylalanine was obtained by the method of Turk, et al. EXAMPLE 14

N-[[[4-(Propoxycarbonyl)phenyl]methoxy]carbonyl]-L- tryptophyl-α-methyl-DL-phenylalaninamide (13)

Propyl 4-(hydroxymethyl) benzoate (0.10 g,

0.5 mmol), 4-nitroρhenyl chloroformate (0.10 g, 0.5 mmol) and pyridine (0.04 mL, 0.5 mmol) were stirred for 18 hours in CH₂Cl₂ (8 mL). The solvent was removed in vacuo and the white residue triturated with EtOAc and filtered. The filtrate was added to a solution of 5 (0.10 g, 0.27 mmol) and 1,1,3,3-tetra-methylguanidine (0.10 mL, 0.81 mmol) in DMSO (2 mL) and stirred for 3.5 hours. The reaction mixture was poured onto H₂O and extracted with EtOAc. The organic layer was washed with 10% citric acid

solution, saturated NaHCO₃ solution, H₂O, and dried (MgSO₄). Further purification by flash column chromatography on silica, eluting with CH₂Cl₂ (95:5) gave 13 as a white foam (0.02 g, 13%); mp 78-105°C; MS (FAB) m/e 586 [M+H]; ¹H NMR (DMSO-d₆) δ 0.97 (3H, t, J 7 Hz, CH₃CH₂), 1.38 (0.5 × 3H, s, α-CH₃), 1.40

(0.5 × 3H, s, α-CH₂), 1.76 (2H, m, CH₂CH₂), 2.80-3.45 (4H, m, CH₂-indole, CH₂Ph), 4.12-4.35 (3H, m, Trp α-H, CH₂CH₂O) , 4.94-5.15 (2H, m, CH₂OCO), 6.95-7.95 (18H, m, Ar, CONH₂, CONH, OCONH, 10.82 (1H, s, indole NH); Anal. (C₃₃H₃₆N₄O₆·0.75 H₂O) C, H, N.

EXAMPLE 15

Boc(α-Me)-DL-PheODhbt (14)

1,3-Dicyclohexylcarbodiimide (4.95 g, 24 mmol) was added to a solution of 1 (6.70 g, 24 mmol) in THF (100 mL) at -15°C and allowed to stir for 5 minutes.3-Hydroxy-1,2,3-benzotriazine-4-(3H)-one (3.91 g, 24 mmol) and an additional volume of THF (20 mL) were added and the mixture stirred at -10°C for 1 hour and at 0°C for 4 hours. After leaving overnight at 5°C a white solid precipitated. This was filtered and dried to give 14 (9.1 g, 89%): ¹H NMR (DMSO-d₆) δ 1.44 (3H, s, α-CH₃), 1.49 (9H, s, t-Bu), 3.06 (1H, d, J 13 Hz, CH'HPh), 3.61 (1H, d, J 13 Hz, CH'HPh), 7.15-7.38 (5H, m, Ph), 7.64 (1H, s, OCONH), 8.02 (1H, 5, J 7.5 Hz, Ar), 8.19 (1H, t, J 7.5 Hz, Ar), 8.33 (2H, d, J 8 Hz, Ar).

EXAMPLE 16

Boc-(α-Me)-DLPheGlyNH₂ (15)

14 (4.24 g, 10 mmol), glycinamide hydrochloride (1.11 g, 11 mmol), and triethylamine (1.39 mL,

11 mmol) in EtOAc (100 mL) were stirred overnight at room temperature. The white solid which precipitated was removed by filtration and washed with EtOAc. The filtrate was washed with 10% citric acid solution, saturated NaHCO₃ solution, H₂O, and dried (MgSO₄). Removal of the solvent in vacuo gave 15 as a white solid (2.05 g, 61%): ¹E NMR (DMSO-d₆) δ 1.16 (3H, s, α-CH₃), 1.43 (9H, s, t-Bu), 2.95 (1H, d, J 13 Hz,

CH₂Ph), 3.26 (1H, d, J 15 Hz, CH₂Ph), 3.46 (1H, br d, J 16.5 Hz, NHCH₂CO), 3.69 (1H, dd, J 16.5 Hz, 6 Hz, NHCH₂CO) , 7.02-7.34 (8H, m, Ar, CONH₂, OCONH), 8.17 (1H, bs, NHCO) .

EXAMPLE 17

(α-Me)-DLPheGlyNHo (16)

15 (2.0 g, 5.7 mmol) was stirred at 0°C in TFA (2 mL) for 15 minutes. The solvent was removed in vacuo and the residue triturated with ET₂O. The white solid formed was filtered and dried to give 16 (1.97 g, 95%): ¹H NMR (DMSO-d₆) δ 1.52 (3H, s, α-CH₃), 3.06 (1H, d, J 14 Hz, CH₂Ph), 3.20 (1H, d, J 14 Hz, CH₂Ph), 3.74 (2H, d, J 5.5 Hz, NHCH₂CO), 7.00-7.40 (7H, m, Ph₂CONH₂), 8.09 (3H, bs, NH₃+), 8.62 (1H, J 5.6 Hz, CONH).

EXAMPLE 18

N-[(Phenylmethoxy)carbonyl]-L-tryptophyl-α-methyl-DL- phenylalanylglycinamide (17)

Hydrobenzotriazolyl tetramethyluronium

hexachlorophosphate (HBTU) (0.19 g, 0.5 mmol) was added to a solution of Z-(L)-Trp (0.15 g, 0.5 mmol), 16 (0.17 g, 0.5 mmol), and N,N-diisopropylethylamine (0.26 mL, 1.5 mmol) in DMF (3 mL) and stirred at room temperature for 45 minutes. Water was added and the mixture extracted with EtOAc. The organic layer was washed with 10% citric acid solution, saturated

NaHCO₃ solution, H₂O, and dried (MgSO₄). Further purification by flash column chromatography on silica, eluting with CH₂Cl₂:MeOH (90:10) gave 17 as a white foam (0.17 g, 61%); mp 92-110°C; MS (FAB) m/e 556 [M+H]; ¹H NMR (DMSO-d₆) δ 1.19 (0.5 × 3H, s, α-CH₃), 1.24 (0.5 × 3H, s, α-CH₃), 2.80-3.30 (4H, m, CH₂-indole, CH₂Ph), 3.40-3.78 (2H, m, CH₂CONH₂) ,

4.25-4.48 (1H, m, Trp-α-H), 4.84-5.06 (2H, m,

CH₂OCO) , 6.88-7.45 (16H, m, Ar, OCONH, CONH₂) ,

7.55-7.75 (2H, m, Ar), 7.80 (0.5 × H, t, CONHCH₂) , 7.88 (0.5 × H, t, CONHCH₂), 8.35 (0.5 × H, s,

NHC(CH₃), 8.41 (0.5 × H, s, NHC(CH₃), 10.86 (1H, s, indole NH); Anal. (C₃₁H₃₃N₅O₃₅· 0.5H₂O) C, H, N.

EXAMPLE 19

N- [(1-Naphthalenylmethoxy)carbonyl]-L-tryptophyl-α-methyl-DL-phenylalanylglycinamide (18)

Diisopropylethylamine (52 μL, 0.3 mmol) was added to a stirred solution of N-[(1-naphthyl-methoxy) carbonyl] tryptophan (0.117 g, 0.3 mmol) and HBTU (0.114 g, 0.3 mmol) in DMF (5 mL) at room temperature. The mixture was stirred for 10 minutes, then 16 (0.105 g, 0.3 mmol) in DMF (5 mL) was added, followed by diisopropyl ethylamine (105 μL, 0.6 mmol) and the reaction mixture stirred for a further

18 hours. The mixture was poured into H₂O (100 mL) and extracted with EtOAc (2 × 50 mL). The organic extracts were combined, washed with 10% citric acid solution (1 × 100 mL), saturated NaHCO₃ solution (1 × 100 mL), H₂O (2 × 100 mL), and dried (MgSO₄). The solvent was removed in vacuo and the residue purified by column chromatography on silica, eluting first with mixtures of EtOAc in hexane (30% to 70%) followed by CH₂Cl₂:MeOH (95:5) to give 18 as a white solid (0.148 g, -81%); MS (FAB) m/e 606 [M+H]: ¹H NMR (DMSO-d₆) δ 1.21 (0.5 × 3H, s, α-CH₃), 1.26

(0.5 × 3H, s, α-CH₃), 2.85-3.78 (6H, m, CH₂-indole, CH₂Ph, Ch₂CONH₂), 4.38 (1H, m, Trp α-H), 5.44 (2H, m, CH₂ naphthyl), 6.92-7.20 (10H, m, Ar/NH), 7.33

(0.5 × H, s, Ar/NH), 7.35 (0.5 × H, s, Ar/NH),

7.52-7.70 (6H, m, Ar/NH), 7.75-8.00 (4H, m, Ar/NH),

8.33 (0.5 × H, s, NH) , 8.35 (0.5 × H, s, NH), 10.72 (1H, s, NH indole); .Anal. (C₃₅H₃₅N₅O₅·0.5H₂O) C, H, N.

EXAMPLE 20

N-[(1-Naphthalenylmethoxy) carbonyl]-L-tryptophyl-α-methyl-L-phenylalanylglycinamide (19)

Prepared by the same method as Compound 18 as in Example 19 in methylphenylalanine and obtained by the method of Tuttle, et al.

EXAMPLE 21

N-[[(2,3-Dimethoxyphenyl)methoxy]carbonyl]-L-tryptophyl-α-methyl-DL-phenylalaninamide (20)

Prepared by the same method as Compound 6 in Example 7, white foam: mp 87-102°C; MS (FAB) m/e 559 [M+H]; ¹H NMR (DMSO-d₆) δ 1.39 (3H, S,α-CH₃), 2.88 (1H, t) and 3.11-3.39 (3H, m, CH₂-indole, CH₂Ph), 3.63 (3H, d, OCH₃), 3.78 (3H, s, OCH₃), 4.21 (1H, m, Trp α-H), 4.93 (2H, s, CH₂O), 6.79-7.78 (17H, m, Ar, CONH₂, CONH, OCONH), 10.76 (1H, s, indole NH), and

(C₃₁H₃₄N₄O₆·0.5 H₂O) C, H, N.

Claims

1. A compound of formula

or a pharmaceutically acceptable salt thereof wherein:

R ¹ is an N-terminal blocking group, from 0 to 4 amino acid residues or hydrogen; R ² is a sidechain of a genetically coded amino acid except glycine;

R ³ is a C-terminal blocking group from 0 to

4 amino acid residues, -OH, or ORⁿ wherein Rⁿ is straight or branched alkyl or cycloalkyl of from 1 to 6 carbon atoms;

R ⁴ is a sidechain of a genetically coded amino acid, except glycine, or

-HC=CH₂,

-C≡CH,

-CH₂-CH=CH₂,

-CH₂C≡CH,

-CH₂Ar,

-CH₂OR,

-CH₂OAr,

-(CH₂)_nCO₂R, or

-(CH₂) NR ⁵R⁶ wherei.n n is an integer of

from 0 to 3, R is hydrogen or lower alkyl, Ar is a mono- or polycyclic unsubstituted or substituted carbo- or heterocyclic aromatic or hydroaromatic moiety; R⁴ and R² cannot be hydrogen;

R¹ and R³ together cannot be more than 4 amino acid residues.

2. A compound according to Claim 1 wherein:

R¹ is H,

Boc,

Fmoc,

Z,

1-Adoc,

2-Adoc,

IVA, or

NVA;

R² is CH₃- or

HOOC-C_H2- ; and

R³ is -NH₂,

-OCH₃, or

-OCH₂Ph.

3. A compound according to Claim 1 selected from MeLys-Trp-Asp-Asn-Gln,

Lys-MeTrp-Asp-Asn-Gln,

Lys-Trp-MeAsp-Asn-Gln,

Lys-Trp-Asp-MeAsn-Gln,

Lys-Trp-Asp-Asn-MeGln,

MeVal-Gly-His-Leu-Met-NH₂,

Val-Gly-MeHis-Leu-Met-NH₂,

Val-Gly-His-MeLeu-Met-NH₂,

Val-Gly-His-Leu-MeMet-NH₂,

MeGlp-His-Trp-Ser-Tyr,

Glp-MeHis-Trp-Ser-Tyr,

Glp-His-MeTrp-Ser-Tyr,

Glp-His-Trp-MeSer-Tyr,

Glp-His-Trp-Ser-MeTyr,

Gly-MeLeu-Arg-Pro-Gly-NH₂, Gly-Leu-MeArg-Pro-Gly-NH₂,

Gly-Leu-Arg-MePro-Gly-NH₂,

MeTyr-Pro-Ser-Lys-Pro,

Tyr-MePro-Ser-Lys-Pro,

Tyr-Pro-MeSer-Lys-Pro,

Tyr-Pro-Ser-MeLys-Pro,

Tyr-Pro-Ser-Lys-MePro,

MeThr-Arg-Gln-Arg-Tyr-NH₂

Thr-MeArg-Gln-Arg-Tyr-NH₂,

Thr-Arg-MeGln-Arg-Tyr-NH₂,

Thr-Arg-Gln-MeArg-Tyr-NH₂,

Thr-Arg-Gln-Arg-MeTyr-NH₂,

Gly-MeTrp-Thr-Leu-Asn,

Gly-Trp-MeThr-Leu-Asn,

Gly-Trp-Thr-MeLeu-Asn,

Gly-Trp-Thr-Leu-MeAsn,

MeLeu-Tyr-Gly-Leu-Ala-NH₂,

Leu-MeTyr-Gly-Leu-Ala-NH₂,

Leu-Tyr-Gly-MeLeu-Ala-NH₂,

Leu-Tyr-Gly-Leu-Aib-NH₂,

MePhe-Phe-Trp-Lys-Thr,

Phe-MePhe-Trp-Lys-Thr,

Phe-Phe-MeTrp-Lys-Thr,

Phe-Phe-Trp-MeLys-Thr,

Phe-Phe-Trp-Lys-MeThr,

MePhe-Phe-Gly-Leu-Met-NH₂,

Phe-MePhe-Gly-Leu-Met-NH₂,

Phe-Phe-Gly-MeLeu-Met-NH₂, and

Phe-Phe-Gly-Leu-MeMet-NH₂.

4. A compound named N-[α-methyl-N-[N-(N-L- tyrosylglycyl) glycyl]-L-phenylalanyl]-L-leucine trifluoroacetate (1:1 salt).

5. A compound named N- [α-methyl-N-[N-(N-L- tyrosylglycyl) glycyl]-D-phenylalanyl]-L-leucine trifluoroacetate (1:1 salt).

6. A compound named N-[[(4-chlorophenyl)methoxy]- carbonyl]-L-tryptophyl-α-methyl-DL- phenylalaninamide.

7. A compound named N-[[[4-(trifluoromethyl)- phenyl]methoxy]carbonyl]-L-tryptophyl-α-methyl- DL-phenylalaninamide.

8. A compound named N-[([1,1'-biphenyl]-4-yl- methoxy)carbonyl]-L-tryptophyl-α-methyl-DL- phenylalaninamide.

9. A compound named N-[(9-anthracenylmethoxy)- carbonyl]-L-tryptophyl-α-methyl-DL- phenylalaninamide.

10. A compound named N-[(1-naphthalenylmethoxy)- carbonyl]-L-tryptophyl-α-methyl-DL- phenylalaninamide.

11. A compound named N-[(1-naphthalenylmethoxy)- carbonyl]-L-tryptophyl-α-methyl-L- phenylalaninamide.

12. A compound named N-[(1-naphthalenylmethoxy)- carbonyl]-L-tryptophyl-α-methyl-D- phenylalaninamide.

13. A compound named N-[[[4-(propoxycarbonyl)- phenyl]methoxy] carbonyl]-L-tryptophyl-α-methyl- DL-phenylalaninamide.

14. A compound named N-[(phenylmethoxy)carbonyl]-L- tryptophyl-α-methyl-DL-phenylalanylglycinamide.

15. A compound named N-[(1-naphthalenylmethoxy)- carbonyl]-L-tryptophyl-α-methyl-DL-phenylalanyl- glycinamide.

16. A compound named N-[(1-naphthalenylmethoxy)- carbonyl]-L-tryptophyl-α-methyl-L- phenylalanylglycinamide.

17. A compound named N-[[(2,3-dimethoxyphenyl)- methoxy]carbonyl]-L-tryptophyl-α-methyl-DL- phenylalaninamide.

18. A pharmaceutical composition comprising an

amount of a compound according to Claim 1 effective to treat pain in a mammal suffering therefrom, and a pharmaceutically acceptable carrier.

19. A method of treating pain in a mammal comprising administering an effective pain treating amount of a compound according to Claim 1.