WO1994018229A1 - 1,2,4-triazinone derivatives and their use in therapy - Google Patents

Abstract

Compounds of formula (I), wherein R1 represents H, NH¿2?, C1-6 alkyl optionally substituted by phenyl or naphthyl, R?6CONH, R7¿OCONH or R8NHCONH; R2 represents H or C¿1-6? alkyl optionally substituted by phenyl; R?3¿ represents H, phenyl or C¿1-6? alkyl optionally substituted by phenyl, naphthyl or C3-8 cycloalkyl; the phenyl and naphthyl groups being optionally substituted; R?4¿ represents H or CONR?9R10; R5¿ represents NH¿2?, NHCOR?11¿, NHCONR12R12a, NHCOOR13 or NHSO¿2?R?14; R6, R7 and R8¿ independently represent H, phenyl or C¿1-6? alkyl optionally substituted by phenyl, naphthyl, 1- or 2-adamantyl or 3-quinuclidinyl; the phenyl and naphthyl groups being optionally substituted; R?9 and R10¿ independently represent H or C¿1-6? alkyl; R?11¿ represents C¿1-6? alkyl, C2-6 alkenyl, phenyl or naphthyl, which groups are optionally substituted by phenyl or naphthyl; the phenyl and naphthyl groups being optionally substituted; R?12¿ represents H, phenyl, naphthyl or C¿1-6? alkyl optionally substituted by phenyl or naphthyl; the phenyl and naphthyl groups being optionally substituted; R?12a¿ represents H or phenyl; R13 represents phenyl or C¿1-6? alkyl optionally substituted by phenyl or naphthyl; the phenyl and naphthyl groups being optinally substituted; R?14¿ represents phenyl, naphthyl or C¿1-6? alkyl optionally substituted by phenyl or naphthyl; the phenyl and naphthyl groups being optionally substituted; R?15¿ represents H or C¿1-6? alkyl; m and n independently represent an integer from 1 to 4 inclusive; and p represents an integer from 3 to 7 inclusive; and pharmaceutically acceptable salts thereof, are useful in therapy, particularly in the treatment of obesity.

Description

1,2.4-Triazinone derivatives and their use in therapy

This invention relates to 1,2,4-triazinone derivatives, processes for their preparation, pharmaceutical formulations including them, and ιθ their πse in therapy, more particu- s larly their use in the treatment of cholecystokinin (CCK) related disorders such as obesity.

CCK is a polypeptide hormone. Its biologically active C-terminal fragments include the octapeptide CCK-8 and the tetrapeptide CCK-4. CCK and its C-terminal fragments are o widely distributed in various organs of the body including the gastrointestinal tract, endocrine glands, and in the peripheral and central nervous systems, and they are believed to play an important role in the regulation of appetite, gastrointestinal dis¬ orders, insulin secretion and central nervous system disorders.

s Many synthetic analogues of CCK fragments are known to possess CCK-like properties (see for example International Patent Application WO 91/19733). These are generally linear polypeptides which are susceptible to hydrolysis by peptidase enzymes and thus may be ineffective when administered orally unless specially formulated. In addition, small peptide molecules are flexible structures and may be relatively non-specific in their 0 ability to bind to receptor sites. It is therefore desirable to obtain molecules which are ^' relatively conformationally constrained and in which the peptide bonds are masked in order to achieve greater stability and specificity of action.

A number of 1,2,4-triazinone derivatives derived from oligopeptides and simple hydra- zines are known (see Sauve et al, Can J Chem, 63, 3089, 1985).

According to the present invention, there are provided compounds of formula I,

wherein

R¹ represents H, NH-_>, C,^ alkyl optionally substituted by phenyl or naphthyl, R⁶CONH, R⁷OCONH or R⁸NHCONH;

R² represents H or C,^ alkyl optionally substituted by phenyl;

R³ represents H, phenyl or C,^ alkyl optionally substituted by phenyl, naphthyl or C₃^ cycloalkyl; the phenyl and naphthyl groups being optionally substituted by C,^ alkyl, C^ alkoxy, halogen or hydroxy; R⁴ represents H or CONR⁹R¹⁰;

R⁵ represents NH₂, NHCOR¹¹, NHCONR^,2R^12a, NHCOOR¹³ or NHS0₂R¹⁴; R⁶, R⁷ and R⁸ independently represent H, phenyl or C^ alkyl optionally substituted by phenyl, naphthyl, 1- or 2-adamantyl or 3-quinuclidinyl; the phenyl and naphthyl groups being optionally substituted by C^ alkyl, C,^ alkoxy, hydroxy, NO;, NH-j, halogen, trifluo- romethyl, C0₂H, CH₂C0₂H, OS0₃H or NHS0₃H; R⁹ and R¹⁰ independently represent H or C,^ alkyl;

R¹¹ represents C-^ alkyl, C₂^ alkenyl, phenyl or naphthyl, which groups are optionally substituted by phenyl or naphthyl; the phenyl and naphthyl groups being optionally substituted by C,^ alkyl, C,^ alkoxy, hydroxy, NO₂, NH->, halogen, trifluoromethyl, CO,H, CH₂C0₂H, OSO₃H or NHSO₃H;

R¹² represents H, phenyl, naphthyl or C,^ alkyl optionally substituted by phenyl or naphthyl; the phenyl and naphthyl groups being optionally substituted by C-^ alkyl, C^ alkoxy, hydroxy, N0₂, NH₂, halogen, trifluoromethyl, benzyl, C0₂H. CH₂C0₂H, OS0₃H or NHS0₃H; R^12a represents H or phenyl; R¹³ represents phenyl or C,^ alkyl optionally substituted by phenyl or naphthyl; the phenyl and naphthyl groups being optionally substituted by C,.₆ alkyl, C_:_₆ alkoxy, hydroxy, N0₂. NH₂, halogen, trifluoromethyl. C0₂H, CH₂C0₂H, OS0₃H or NHS0₃H; R¹⁴ represents phenyl, naphthyl or C,^ alkyl optionally substituted by phenyl or naphthyl; s the phenyl and naphthyl groups being optionally substituted by C,^ alkyl, C alkoxy, hydroxy, N0₂, NH₂, halogen, trifluoromethyl, C0₂H, CH₂C0₂H, OS0₃H or NHS0₃H; R¹⁵ represents H or C^ alkyl; m and n independently represent an integer from 1 to 4 inclusive; and p represents an integer from 3 to 7 inclusive; o and pharmaceutically acceptable salts thereof (hereinafter referred to as "the compounds of the invention").

Pharmaceutically acceptable salts of the compounds of formula I include acid addition or basic salts, for example, salts of mineral acids, for example, hydrochloric or s hydrobromic acids; or salts of organic acids, for example, formic, acetic or lactic acids. The acid may be polybasic, for example sulphuric, fumaric, maleic or citric acid. Basic salts may include, for example, salts of ammonium hydroxide, sodium hydroxide, potas¬ sium hydroxide and calcium hydroxide.

0 The compounds of the invention may exist in different isomeric forms, including optical geometric and tautomeric isomers. All are included within the scope of the invention.

Alkyl groups which R², R³, R⁶, R⁷, R⁸. R⁹, R¹⁰, R^u, R¹², R¹³, R¹⁴ and R^1S may represent include both straight chain and branched groups, for example methyl, ethyl, propyl, 5 isopropyl, n-butyl, isobutvl, s-butyl and t-butyl. Cycloalkyl groups which may be included in the definition of R³ include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl. Alkenyl groups which R¹¹ may represent include 2-propenyl, 2-butenyl and 2-methyl-2-propenyl.

o The optionally substituted phenyl and naphthyl groups which R³, R⁶, R⁷, R⁸, R^u. R¹², R¹³ and R¹⁴ may represent or include may be substituted by more than one group.

We prefer compounds of the invention in which: R¹ is R⁶CONH or R⁷OCONH, for example t-butyloxycarbonylamino or isopropyloxycar- bonylamino; R² is H;

R³ is C,^ alkyl substituted by phenyl, for example benzyl; R⁴ is H or CONH₂, CONH₂ being most preferred;

R⁵ is or NHCOR¹¹ or NHCONHR¹², NHCOR¹¹ being most preferred; R^u is C_w alkyl substituted by phenyl or more preferably C₂^ alkenyl substituted by phenyl (the phenyl group preferably being substituted by OH or OS0₃H); R¹² is phenyl or phenyl substituted by methyl; m is 1; n is 1; and p is 4.

The preferred stereochemistry of certain chiral centres of compounds of formula I is shown in formula LA,

According to another aspect of the invention, there is provided a process for the produc¬ tion of a compound of the invention, which comprises: (a) preparing a compound of formula I in which R² is C alkyl optionally substi¬ tuted by phenyl, R⁵ is NHCOOR¹³ and R¹³ is C,.₆ alkyl optionally substituted by phenyl or naphthyl, by reacting a compound of formula II,

in which R² and R^s are as defined immediately above and R³, R\ n and p are as defined above, with a compound of formula III,

H

in which R¹, R¹⁵ and m are as defined above;

(b) preparing a compound of formula I in which R⁵ is NHCONHR¹² by reacting the corresponding compound of formula I in which R⁵ is NH₂ with an isocyanate of formula R¹²NCO in which R¹² is as defined above;

(c) preparing a compound of the formula I in which R⁵ is NHCOR¹¹ by reacting the corresponding compound of formula I in which R^s is NH₂ with an acid of formula RⁿCOOH in which Rⁿ is as defined above, or an activated carboxylic acid derivative thereof; (d) preparing a compound of formula I in which R⁵ is NHS0₂R¹⁴ by reacting the corresponding compound of formula I in which R⁵ is NH₂ with a sulphonyl halide of formula R¹⁴S0₂X^d in which R¹⁴ is as defined above and X° represents halogen;

(e) preparing a compound of formula I in which R⁵ is NHCONR^I2(C₆H₅) by react¬ ing the corresponding compound of formula I in which R⁵ is NH₂ with a compound of formula ( H_s)R¹²NCOX^e in which R¹² is as defined above and X^e represents halogen; or

(f) removing a protecting group from a compound of formula I in which one or more of the amino, hydroxy or carboxy groups is protected; and where desired or necessary converting the resulting compound of formula I into a pharmaceutically acceptable salt thereof or vice versa.

The reaction of process (a) may be carried out in the presence of a base, for example a tertiary amine such as N,N-diisopropylethylamine and an acid activating reagent, for example, pivaloyl chloride. An inert aprotic solvent, for example THF may be used and the reaction may be conducted at a temperature of, for example, from 0-50°C.

The reaction of process (b) may be carried out in an inert solvent, for example, DMF in the presence of a base such as N-methylmorpholine or N.N-diisopropylethylamine, and at a temperature of, for example, from 0-50°C.

The reaction of process (c) may be carried out with acid chlorides or activated esters of the acid. A suitable activating reagent is N-hydroxysuccinimide. The reaction may be carried out under similar conditions to those described for reaction (b) above.

In the reaction of process (d) halogens that X^d may represent include chlorine and bromine. The reaction may be carried out under similar conditions to those described for reaction (b) above.

In process (e), halogens which X may represent include chlorine and bromine. The reaction may be carried out in an inert solvent, for example DMF, at a temperature of 0-25°C.

In the reaction of process (f), removal of the protecting group depends upon the nature of the protecting group and includes acidic or basic cleavage or hydrogenolysis. Suitable carboxy protecting groups include benzyl and C-^ alkyl. Suitable amine protecting groups include benzyl and benzyloxycarbonyl, which latter is readily removed by hydrogenolysis or hydrogen bromide in acetic acid. Other groups that may be men- tioned include t-butyloxycarbonyl (Boc), which is removed by cold trifluoroacetic acid or hydrochloric acid in ethyl acetate. Conversion of compounds of formula I in which R² is C,.₆ optionally substituted by phenyl to compounds in which R² is H may be achieved by hydrolysis or. when R² is benzyl, by hydrogenolysis. Further protecting groups and methods for their removal are described in 'Protective Groups in Organic Synthesis' by T W Greene and P G M Wuts, John Wiley and Sons Inc, 1991.

Compounds of formula II may be obtained by: (1) reacting a compound of formula IV, i v

P g NH .C 0₂ H

( C H₂ ) - NHC O - 13

in which R¹³ and p are as defined above, and Pg is an amino-protecting group, with a compound of formula V,

in which R² is C^ alkyl optionally substituted by phenyl, n is as defined above and R¹⁶ represents C,^ alkyl, to give the corresponding compound of formula VI.

(2) reacting the compound of formula VI with Lawesson's reagent to form the corresponding thioamide of formula VII,

(3) reacting the compound of formula VII with a hydrazine of the formula H₂NNHCHR³R⁴ in which R³ and R⁴ are as defined above, to give the corresponding compound of formula VIII,

(4) removal of the protecting group Pg to give the corresponding compound of formula II in which R^s is NHCOOR¹³.

In step (1) the protected amino acid of formula IV is converted to an activated carbox- ylic acid derivative with, for example, pivaloyl chloride in the presence of a base, for example N,N-diisopropylethylamine in an inert solvent such as THF. The activated acid is then condensed with the protected amino acid derivative of formula V at a tempera- ture of, for example, 0-50°C to give the dipeptide of formula VI.

In step (2) the carbonyl group of the peptide linkage is converted to the thiocarbonyl group with Lawesson's reagent [2,4-bis(4-methoxyphenyl)-l,3-dithia-2,4-diphosphetane- 2,4-disulphide], in an aprotic solvent, for example THF or DME or mixtures thereof, and at a temperature of from 10-50°C.

In step (3) the thio compound of formula VII is reacted with the hydrazine compound in the presence of mercuric acetate in an inert solvent, for example THF and at a temperature of 10-50°C, whereupon cyclization to the 1,2,4-triazinone derivative VIII occurs.

In step (4) the protecting group Pg is selectively removed by conventional methods as described herein to give the compound of formula II.

Compounds of formulae III, IV and V are either well known or may be prepared from known compounds by conventional methods or suitable modifications thereof as des- cribed in the examples. Some hydrazines of formula H₂NNHCHR³R⁴ are known or available by conventional methods. Others are available using the methods of Evans et al, J Am Chem Soc, Vol 112, N° 10, p4011 and Tetrahedron, Vol 44, N° 17, p5525, 1988.

5 It will be clear to those skilled in the art that in the preparation of the compounds of the invention protection of reactive functional groups, other than those between which reaction is desired, may be necessary. In addition, some groups may need to be added in protected form, and then deprotected: for example in process (b), when R¹² and R^12a represent H, the compound of formula I may be reacted with benzyl isocyanate followed ιo by hydrogenation to provide a compound of formula I in which R⁵ is NHCONH₂. This may be achieved by conventional methods, for example as set out in 'Protective Groups in Organic Synthesis' mentioned above.

Pharmaceutically acceptable salts may be formed by reacting the free base, or a salt is thereof with one or more equivalents of the appropriate acid. The reaction may be carried out in a solvent in which the salt is insoluble or in which the salt is soluble or in mixtures of the solvents. Acid addition salts may be converted to the corresponding base, for example, by reacting the salt with sodium hydroxide in water at room tempera¬ ture.

20

Resolution of compounds with asymmetric centres may be accomplished by methods well known in the art, for example, by separation of their diastereoisomeric salts, chro- matography on a chiral column or asymmetric syntheses. Methods of resolution are described in J March, 'Advanced Organic Chemistry', 3rd Edition, Wiley Interscience, 25 1985.

The compounds of the invention have the ability to bind to cholecystokinin receptors. Distinct CCK receptors in peripheral and brain tissues have been classified as CCK-A and CCK-B receptors respectively. Differentiation between agonist and antagonist 30 interactions at CCK receptors can be determined by functional assays. Whilst not being limited by theory, activation of CCK-A receptors in peripheral tissues plays an important role in the control of appetite, pancreatic secretion, gut motility and gall bladder con¬ traction. Thus compounds with agonist activity at CCK-A receptors have utility in the treatment of obesity, bulimia and motility disorders and compounds with antagonist or partial agonist activity at CCK-A receptors may have utility in gastrointestinal disorders such as irritable bowel syndrome, ulcers, excess pancreatic or gastric secretion, acute pancreatitis and motility disorders. Compounds with agonist or antagonist activity at the s CCK-A receptor may have utility in the treatment of dopamine related movement disorders including Parkinson's disease and dyskinesias including tardive dyskinesia. Compounds with agonist activity at the CCK-B receptor may have utility in the treat¬ ment or prophylaxis of neuronal damage caused by cerebral ischaemia, stroke, hypoxia or trauma. Compounds with antagonist activity at the CCK-B receptor may have utility ιo in the treatment of anxiety and pain. Other CCK-related disorders which may be men¬ tioned are neuroleptic disorders, disorders of memory and cognition, Huntington's chorea, psychosis, schizophrenia, diabetes and substance abuse. The compounds of the invention may be useful in a number of the above disorders.

is In vitro Assays

a) CCK-A Receptor Affinity

CCK-A receptor affinity was measured by the displacement of Bolton Hunter [¹²⁵I]- CCK-8 or [³H]-MK 329 from rat pancreas according to the general procedure of Chang, o Lotti, Chan and Kunkel (Molecular Pharmacology, 30:212-216, 1986).

b) CCK-B Receptor Affinity

CCK-B receptor affinity was measured by the displacement of Bolton Hunter [¹²⁵I]-CCK- 8 from rat cortex according to the general procedure of Chang and Lotti (Proc Natl 5 Acad Sci, 83:4923-4926, 1986).

Functional Assays For CCK-A Agonist/Antagonist Activity

a) Contraction of Guinea Pig Gallbladder o The ability of a compound to stimulate guinea pig gallbladder contraction was measured by a modification of the procedure described by Rubin et al (J Pharm Sci, 58:955-959, 1969). b) Phosphatidyl Inositol Hvdrolvsis

The ability of a compound to stimulate phosphatidvl inositol hydrolysis in guinea pig pancreatic tissue slices was measured according to the procedure of Lin et al (J Pharma¬ col Exp Ther. 236:729-734, 1980).

In vivo Functional Assay

Feeding Inhibition

The ability of a compound to inhibit food intake in rats was measured by a modification of the procedure described by Cox and Maichel (J Pharmacol Exp Ther, 181:1-9, 1972). Male Sprague Dawley rats (300-400g) were trained to eat for a three hour period during the dark cycle. To assess anorectic potency, each group of rats was administered a different dose of compound intraperitoneally (in 0.5ml of water). Pre-weighed food jars containing powdered chow (Purina) were introduced 15 minutes later, just after the start of the dark cycle. Food intake was measured after 30 minutes and 3 hours of feeding by weighing the jars. Treatment effects on food intake were compared with control values to determine the magnitude of feeding inhibition.

The compounds of the invention may be administered by a variety of routes, for example, intraperitoneally, intravenously, intramuscularly, subcutaneously, intranasally or orally. The dosage of the compound of the invention will depend on several factors, including the requirements of the recipient and the particular compound employed, but will typically be in the range 0.3mg to 300mg per kg of body weight per day, either as a single dose or divided among two to four doses.

Examples of suitable adjuvants, diluents or carriers are: for tablets and dragees - lactose, starch, talc or stearic acid: for capsules - tartaric acid or lactose: for injectable solutions - physiological saline solution, alcohols, glycerin or vegetable oils; for intranasal solutions - physiological saline solution.

The formulations may also contain suitable preserving, stabilising and wetting agents, solubilisers (eg a water-soluble cellulose polymer such as hydroxypropyl methylcellulose, or a water-soluble glycol such as propylene glycol), sweetening and colouring agents and flavourings. The formulations may, if desired, be in sustained release form.

Th invention provides a pharmaceutical formulation including (preferably less than 80%, and more preferably less than 50% by weight) a compound of the invention in admixture with a pharmaceutically acceptable adjuvant, diluent or carrier.

The invention also provides a compound of the invention for use as a pharmaceutical, and the use of a compound of the invention in the manufacture of a medicament for the treatment of obesity. The invention also provides a method of treatment of obesity which comprises administering a therapeutically effective amount of a compound of the invention to a patient suffering from such a condition; and a method of improving the bodily appearance of a mammal which comprises administering to that mammal a compound of the invention until a cosmetically beneficial loss of body weight has occurred.

The compounds of the invention may have the advantage that they are more efficacious, more potent, longer acting, more stable (particularly to enzymatic degradation), more selective, less toxic, give rise to fewer side effects, eg lack of emesis, are more readily absorbed, are quicker acting, are more convenient to administer (for example because they can be taken orally) or have other advantageous effects compared with compounds of the prior art.

The inclusion of a tetrahydro-l,2,4-triazin-6-one group in a peptide chain to restrain its conformation may be useful in peptide structures other than those of formula I, as defined above. There is therefore provided a compound including a group of formula A,

wherein R₍, R_i+] and R_i+2 independently represent amino acid side chains, or a tautom- eric form thereof. There is further provided a process for the production of a com¬ pound including a group of formula A, as defined above, which comprises reaction of a compound including a group of formula Al,

wherein Rj and R_i+1 independently represent amino acid side chains, or protected derivatives thereof, and L is a leaving group, with a compound including a group of formula All,

wherein R_i+2 represents an amino acid side chain, or a protected derivative thereof. Leaving groups which L may represent include C,^ alkoxy. The reaction is preferably carried out in the presence of mercuric acetate in an inert solvent, for example THF, at a temperature of 10-50°C. Protection and deprotection of the amino acid side chains may be achieved by conventional methods, for example as set out in 'Protective Groups in Organic Synthesis' mentioned above.

The invention is illustrated by the following examples.

Examples

In keeping with standard peptide nomenclature as recommended by the IUPAC-IUB Joint Commission on Biochemical Nomenclature (Eur J Biochem, 1984, 138, 9), abbrevi- ations for amino acid residues and amide bond (ie -CO-NH-) replacements are used herein. The 1,3-diradical of the tetrahydro-6-oxo-l,2,4-triazine ring structure may represent an amide bond replacement. The abbreviations, f [2(H)Taz] or ψ[4(H)Taz], wherein 2(H) and 4(H) locate the position of the NH group and Taz represents tetrahydro-6-oxo- 1,2,4- triazine, correspond to l,2,5,6-tet.-ahydro-6-oxo-l,2,4-triazine or l,4,5,6-tetrahydro-6-oxo- s 1,2,4-triazine respectively:

The 4-5-6 fragment of the triazine ring may be derived from an L- or D-α-amino acid such that the amino and carboxyl residues are at the 4 and 5 positions respectively and ιo the α-side chain of the α-amino acid is located at the 5-position; eg if the amino acid is aspartic acid then the abbreviation ψ[2(H)Taz(Asp)] represents:

When this amide bond replacement links two α-amino acids, eg. lysine and phenyl- i5 alanine amide, then the abbreviation H-Lysψ[2(H)Taz(Asp)]Phe-NH₂ represents the structure:

When this amide bond replacement links an α-amino acid eg lysine, with an amine eg 0 phenylethvlamine (Pea) then the abbreviation H-Lysψ[2(H)Taz(Asp)]Pea represents the structure:

Similarly, the abbreviation ψ[CSNH] indicates that the amide bond of a peptide has been replaced by a thiocarbonyl amide bond.

All amino acid residue sequences are represented herein by formulae whose left to right orientation is in the conventional direction of amino-terminus to carboxv terminus. All α-amino acid residues identified herein have the natural L-configuration unless otherwise_^ designated with "D" (eg Dlys or DAsp).

The following general abbreviations are used in the examples:

2ClPac (2-chlorophenyl)aminocarbon;

3Hci trans-3-hydroxycinnamoyl 4Hci trans-4-hydroxycinnamoyl

Aci trans-4-aminocinnamoyl

AcOH or HOAc acetic acid

Bac benzylaminocarbonyl

BnPac 2-benzylphenylaminocarbonyl Boc tert-butyloxycarbonyl

Bz benzoyl

Cbz benzyloxycarbonyl

CI chemical ionization

Ci trans-cinnamoyl DCC dicyclohexylcarbodiimide

Dhci trans-3,4-dihydroxycinnamoyl

DIEA N,N-diisopropylethylamine DME 1.2-dimethoxyethane

DMF dimethylformamide dPac diphenylaminocarbonyl

Eoc ethyloxycarbonyl s ES electrospray

EtOAc ethyl acetate

FAB fast atom bombardment

Hbc 4'-hydroxy-4-biphenylcarbonyl

Hnp 2-(6-hydroxynaphthylcarbonyl)

10 HOBt 1 -hydroxybe nzotriazole

HOSu N-hydroxysuccinimide

HPLC high pressure liquid chromatography

Hpp 3-(4-hydroxyphenyl)propanoyl

IBCF isobutylchloroformate 5 IpOC isopropyloxycarbonyl

Ivac isovalerylcarbonyl or isobutvlcarbonyl

MeOH methanol

Moc methyloxycarbonyl

MS mass spectrum o Nac 2-naphthylaminocarbonyl

Nci trans-4-nitrocinnamoyl

NMM N-methylmorpholine

Npc 2-naphthylcarbonyl

OBn benzyloxy 5 OBt N-oxybenzotriazole

OMe methoxy

OSu N-oxysuccinimide

Pac phenylaminocarbonyl

Pea 2-phenylethylamine Peac phenylethylaminocarbonyl

SE sulphate ester (for example 4HciSE represents the sulphate ester of trans-4-hydroxycinnamoyl)

Tac (2-methylphenyl)aminocarbonyl TBTU 0-(lH-benzotriazol-l-yl)-N,N,N',N'-tetramethvluroniumtetrafluoro- borate

TEA triethylamine TFA trifluoroaceiic acid THF tetrahydrofuran Tos (2-methylphenyl)sulphonyl

The following peptide abbreviations are used in the examples:

Asp aspartic acid

Asp(OBn) aspartic acid beta-benzyl ester

DAsp D-aspartic acid

Cha cyclohexylalanine

Glu glutamic acid Lys lysine

DLys D-lysine

Orn ornithine

DOrn D-ornithine

Phe phenylalanine DPhe D-phenylalanine

HPhe homophenylalanine

Phe-NH₂ phenylalanine amide

Trp tryptophan

DTrp D-tryptophan

ε-derivatives of lysine are indicated as Lys(der), where "der" is the group attached to the ε-amine group: for example Lys(Tac) represents ε-(2-methylphenyl)aminocarbonyllysine.

It should be noted that the title compounds of Intermediates 17-29 below are within the scope of the present invention.

Intermediate 1 H-AspfOBnVOMe Thionyl chloride (4.7ml. 0.0646mol) was added slowly to methanol (160ml) at 0-5°C. To this solution was added Boc-Asp(OBn)-OH (17.4g, 0.0538mol) followed by warming to ambient temperature over 1 hour. The solution was concentrated under reduced pres¬ sure to give an oil which was dissolved in ether (506ml) and extracted with water (2x250ml). The ether layer was dried over MgS0₄, filtered and concentrated to yield Boc-Asp(OBn)-OMe as an oil (12.1g). The aqueous layer was basified to pH 11 with 10% Na₂C0₃ (200ml), then extracted with ether (3x130ml). This second ether layer was dried over MgS0₄, filtered, and concentrated to yield the title compound (4.52g) as an oil.

A solution of ethyl acetate (60ml) was saturated with HC1 below 5°C. To this was added the Boc-Asp(OBn)-OMe prepared above (12.1g) in ethyl acetate (60ml) followed by stirring for 1 hour below 5°C. The solution was then concentrated to an oil (8.23'g), redissolved in ethyl acetate (100ml) and washed with saturated NaHC0₃ (100ml) and saturated NaCl (100ml). The organic layer was dried over MgS0₄, filtered and concen¬ trated under low pressure followed by drying briefly under high vacuum to yield a further portion of the title compound (5.62g) as an oil; combined yield 10.14g (0.0428mol, 79.5%). MS (CI) m/e: 238 (M+H)⁺.

Intermediate 2

Boc-LvsfCbzVAspfOBnVOMe

Boc-Lys(Cbz)-OH (6.83g, 0.018mol) was dissolved in THF (380ml) below 5°C followed by addition of DIEA (4.09g, 0.0316mol) and pivaloyl chloride (2.67g, 0.022mol) followed by stirring for 0.5 hour. Intermediate 1 (5.0g, 0.021mol) was added followed by warming to ambient temperature over 0.5 hour. The reaction mixture was concentrated to a residue and then dissolved in EtOAc (380ml) and washed with IN KHS0₄ (190ml), saturated NaHC0₃ (2x190ml) and saturated NaCl (2x95ml). The organic layer was dried over MgS0₄, filtered and concentrated under reduced pressure to a residue (12.7g). This product was purified by preparative HPLC (two Waters Porasil Prepaks, solvent gradient 0-2% MeOH in CHC1₃ over 1 hour, 60ml/min). Upon concentration the resi¬ due was dried under high vacuum overnight to yield the title compound as a clear foam, 4.4g (7.34mmol, 40.8%). MS (FAB) m/e: 600 (M+H)⁺. A second similar experiment yielded 7.35g (0.0122mol, 67.8%) of the same substance.

Intermediate 3 s Boc-LvsfCbz')iljrCSNH]-AspfOBn OMe

Intermediate 2 (4.40g, 7.34mmoi) was dissolved in 88ml dry THF. Lawesson's reagent (4.3 lg, 0.0104mol) was added followed by stirring overnight at ambient temperature. DME (44ml) was added followed by stirring for 2 hours. Additional Lawesson's reagent o (2.01g, 5.0mmol) was added followed by stirring overnight. The mixture was filtered through celite and concentrated in vacuo to yield a clear oil. This product was purified by preparative chromatography (two Prepaks, 60ml/min, solvent gradient 20-60% EtOAc in hexane over 1 hour). Upon concentration the residue was dried under high vacuurn overnight to yield the title compound as a foam, 3.17g (5.15mmol, 70.1%). MS (FAB) m/e: 616 (M+H)⁺.

Intermediate 4 Boc-LvsrCbz r2rH1Taz[AspfOBn)]1Pea

Intermediate 3 (3.15g, 5.12mmol) was dissolved in 140ml dry THF to which was added phenylethyl hydrazine [liberated by extraction of phenylethyl hydrazine sulphate (4.80g, 0.0205mol) from 1.0N NaOH with methylene chloride (50ml) followed by concentration under reduced pressure, 1.39g, 0.0102mol] and Hg(OAc)₂ (3.2g, 0.0102mol) followed by stirring at ambient temperature for 3 hours. Phenylethyl hydrazine (1.39g, 0.0102mol) and Hg(OAc)₂ (3.2g, 0.0102mol) were added a second time followed by stirring over¬ night at ambient temperature. The mixture was filtered through celite and concentrated in vacuo to yield a residue. The residue was purified by preparative HPLC (two Pre¬ paks, 60ml/min, solvent gradient 20-60% EtOAc in hexane over 1 hour). Fractions con¬ taining the product were combined and concentrated under reduced pressure to yield a white solid (3.1g). The solid was recrystallized by dissolving in ethyl acetate (31ml) followed by addition of hexanes (31ml) and cooling to yield the title compound as a white solid which was collected and dried under high vacuum at 40°C: yield 2.4g (3.5mmol. 68.3%), mp 117-119°C. MS (FAB) m/e: 686 (M+H)⁺. Example 1 Boc-Trp-LvsfCbz τjj[2fH^{^}lTaz[AsprθBn)llPea

Ethyl acetate (60ml) was saturated with HCl gas below 5°C. A solution of Intermediate 4 (1.2g, 0.00175mol) in ethyl acetate (60ml) was added followed by stirring to ambient temperature over 1.5 hours. This solution was concentrated under reduced pressure to yield H-Lys(Cbz)ψ[2(H)Taz[Asp(OBn)]]Pea as the HCl salt.

To a solution of Boc-Trp-OH (0.56g, 1.84mmol) in THF (20ml) at 0-5°C was added DIEA (0.565g, 4.37mmol) and pivaloyl chloride (0.222g, 1.84mmol) followed by stirring for 0.5 hour. A suspension of the above H-Lys(Cbz)ψ[2(H)Taz[Asp(OBn)]]Pea in THF (10ml) was slowly added followed by stirring at 0-5°C for 2 hours. The reaction mixture was concentrated to a residue, dissolved in EtOAc (50ml) and washed with IN KHS0₄ (2x25ml), saturated NaHC0₃ (2x25ml), saturated NaCl (2x12.5ml). The organic layer was dried over MgS0₄, filtered and concentrated under reduced pressure to yield a solid which was purified by preparative HPLC (one Porasil Prepak, 60ml/min, solvent gradient 50-100% EtOAc in Hexane over 1 hour). Fractions containing the product were com¬ bined and concentrated under reduced pressure to yield the title compound as a white solid which was dried under high vacuum; yield 1.09g (1.25mmol, 71.4%). A sample was triturated with ether, collected and dried at 40°C under high vacuum; mp 103-106°C. MS (FAB) m/e: 872 (M+H)⁺.

Example 2 Boc-Trp-LvsfCbz')iH2fH^N.TazfAsp ]Pea

To a solution of the product of Example 1 (200mg, 0.23mmol) in a mixture of THF (10ml) and H₂0 (5ml) at ambient temperature was added IN NaOH (0.57ml, 0.57mmol) followed by stirring for 6 hours. The solution was acidified to pH 3 with HOAc and extracted with EtOAc (24ml, 16ml). The organic layers were dried over MgS0₄, fil- tered and concentrated under reduced pressure to yield an oil. The oil was triturated with hexane (2x8ml), then ether/hexane [1:3] (8ml) to yield a solid which was collected and rinsed with ether/hexane [1:3] (2x4ml) then dried overnight under high vacuum to give the title compound; yield 130mg (0.167mmol, 72.4%); mp 98-103°C. MS (FAB): m/e 782 M+H)⁺.

Example 3 Boc-Trp-LvsιJj[2fH1TazfAsp Pea

The product of Example 1 (1.18g, 1.35mmol) was dissolved in HO Ac (52ml) and 10% Pd/C catalyst (0.355g) was added followed by hydrogenation in a Parr apparatus over¬ night at ambient temperature. The mixture was filtered to remove the catalyst and concentrated under high vacuum to a light red residue. This residue was triturated with ether, collected, and dried under high vacuum to yield the title compound as a light pink powder, yield 0.786g (1.21mmol, 89.8%), mp 128-132°C. MS (FAB) m/e: 648 (M+H)⁺.

Example 4 Boc-Trp-Lvs(Υac') rf2(Η)TazfAsp^N)]Pea

The product of Example 3 (324mg, 0.500mmol) was dissolved in DMF (32ml) and cooled to 0-5°C followed by the addition of NMM (126mg, 1.25mmol) and 2-methylph- enyl isocyanate (67mg, 0.500mmol) in succession. This solution was stirred at ambient temperature for 0.5-2.0 hours. The solution was concentrated under high vacuum and the residue was purified by preparative reversed phase HPLC (2.5x10cm. C-18 bond- apak column, 15ml min, solvent gradient 60-75% MeOH in H₂0 over 0.5 hour buffered with 0.2% TEA and 0.2% HOAc). Fractions containing the product were combined, concentrated under reduced pressure, reconstituted with H₂0, and reconcentrated to produce a slurry. The white solid was collected, rinsed with water and dried in a vac¬ uum overnight to yield the title compound as a white powder, yield 175mg (0.224mol, 44.8%), mp 103-105°C. MS (FAB) m/e 782 (M+H)⁺.

Example 5 Boc-Trp-Lvsf4Hci ψ[2rH)TazrAsp)]Pea

Using the procedure of Example 4. the product of Example 3, (324mg, 0.500mmol) was reacted with 4-hydroxycinnamic acid N-hydroxysuccinimide ester (0.131g, 0.500mmol) for 18 hours. Purification by the method of Example 4 provided the title compound as a white powder, yield 125mg (0.157mmol, 31.5%), mp 129-132°C. MS (FAB) m/e: 794 (M+H)⁺.

s Example 6

Boc-Trp-LvsrHpp )τlr[2rH^s)TazfAsp ]Pea

Using the procedure of Example 4, the product of Example 3, (324mg, 0.500mmol) was reacted with 3-(4-hydroxyphenyl)propanoic acid N-hydroxysuccinimide ester (0.131g, o 0.500mmol) overnight. Purification by the method of Example 4 provided the title compound as a white powder, yield 138mg (0.173mmol, 34.6%), mp 179-183°C. MS (FAB) m/e: 797 (M+H)⁺.

Example 7 Boc-Trp-LvsrPac^N)ιif[2fH TazrAsp^N)]Pea

Using the procedure of Example 4, the product of Example 3, (324mg, 0.500mmol) was reacted with phenyl isocyanate (59.6mg, 0.500mmol) for 18 hours. Purification by the method of Example 4 provided the title compound as a white powder, yield 198mg (0.258mmol, 51.6%), mp 110-113°C. MS (FAB) m/e: 768 (M+H)⁺.

Example 8 Boc-Trp-LvsfNac τ|r[2(ΗyrazfAsp)]Pea

Using the procedure of Example 4, the product of Example 3, (200mg, 0.309mmol) was reacted with 2-naphthyl isocyanate (52.2mg, 0.309mmol) for 18 hours. Purification by the method of Example 4 provided the title compound as a white powder, yield 77mg (0.094mmol, 30.5%), mp 112-116°C. MS (FAB) m/e: 818 (M+H)⁺.

Example 9

Boc-Trp-Lvsf2ClPac')ilr[2fH)TazfAsp')]Pea Using the procedure of Example 4. the product of Example 3, (237mg, 0.366mmol) was reacted with 2-chlorophenyl isocyanate (57.3mg, 0.366mmol) overnight. Purification by the method of Example 4 provided the title compound as a white powder, yield 86mg (0.107mmol, 29.3%), mp 98-104°C. MS (FAB) m/e: 802 (M+H)⁺.

Intermediate 5 Boc-DLvsrCbzVAspfOBnVOMe

In a procedure similar to that used to prepare Intermediate 2, Boc-DLys(Cbz)-OH (15.2g, 0.0491mol) was dissolved in THF (840ml) below 5°C followed by addition of

DEA (9.07g, 0.0702mol) and pivaloyl chloride (5.92g, 0.050mol) followed by stirring for

1.0 hour. Intermediate 1 (ll.lg, 0.0468mol) was added followed by warming to ambient temperature over 0.5 hour. The reaction mixture was concentrated to a residue fol- lowed by dissolving in EtOAc (500ml) and washing with IN KHS0 (200ml), saturated NaHC0₃ (2x200ml) and saturated NaCl (2x100ml). The organic layer was dried over

MgS0₄, filtered and concentrated under reduced pressure to a residue (12.7g). The product was purified by preparative HPLC (two Prepaks, solvent gradient 10-50%

EtOAc in Hexanes over 1 hour, 60ml/min). Upon concentration the residue was dried under high vacuum overnight to yield the title compound as a clear foam, 15.2g (0.0253mol, 63.3%). MS (FAB) m/e: 600 (M+H)⁺.

Intermediate 6 Boc-DLvsfCbz Ur[CSNH]AspfOBnVOMe

In a procedure similar to the preparation of Intermediate 3, Intermediate 5 (7.60g, 0.0127mol) was dissolved in 240ml dry THF. Lawesson's reagent (7.23g, 0.0179mol) was added followed by stirring overnight at ambient temperature. Additional Lawesson's reagent (3.75g, 0.0093mol) was added followed by stirring overnight. The mixture was filtered through celite and concentrated under reduced pressure to yield a clear oil. This product was purified by the preparative HPLC method used for Intermediate 3 to yield the title compound as a white foam, 7.22g (0.0117mol, 92.6%), MS (FAB) m/e: 616 (M+H)'. Intermediate 7 Boc-DLvsfCbz Ur[2fHVraz[Asp(OBn ]Pea

Intermediate 6 (7.7g, 0.0117mol) was dissolved in 320ml dry THF and cooled to 5°C. To this solution was added phenylethyl hydrazine (3.30g, 0.024mol) and Hg(OAc)₂ (7.47g, 0.0234mol) followed by stirring at 5°C ambient temperature for 1.5 hours. Phenylethyl hydrazine (1.48g, 0.0109mol) and Hg(OAc)₂ (3.73g, 0.0117mol) were added a second time followed by stirring overnight at ambient temperature. The mixture was filtered through celite and concentrated in vacuo to yield a residue. The residue was purified by the preparative HPLC method used in the preparation of Intermediate 4 to yield the title compound as a foam which was collected and dried under high vacuum at 40°C; yield 5.5g (8.2mmol, 68.6%). The foam was crystallized by trituration in hexane/EtOAc [1:1] (110ml) and collected to yield the product as a white solid which was dried under high vacuum overnight; yield 3.42g, mp 84-87°C. MS (FAB) m/e: 686 (M+H)⁺.

Example 10 Boc-Trp-DLvsrCbz^[2fHYTaz[Asp(OBn ]Pea

In a procedure similar to Example 1, Intermediate 7 (4.2g, 0.00612mol) in EtOAc (100ml) was deprotected by addition to a solution of saturated HCl, in EtOAc ( 100ml). After 1 hour the reaction was concentrated under reduced pressure to yield H- DLys(Cbz)ψ[2(H)Taz[Asp(OBn)]]Pea as the HCl salt. Boc-Trp-OH (1.96g, 0.00643mol) was activated in THF (100ml) at 0-5°C with DIEA (1.98g, 0.0153mol) and pivaloyl chlor- ide (0.775g, 0.00643mol) followed by stirring for 0.5 hour and was then treated with the above H-DLys(Cbz)ψ[2(H)Taz[Asp(OBn)]]Pea in THF (20ml) at 0-5°C for 2 hours. The reaction mixture was concentrated, extracted and purified by preparative HPLC in essentially the same manner as Example 1 to yield the title compound as a foam after drying under high vacuum: yield 4.2g (0.00482mol, 78.8%); mp 70-74°C. MS (FAB) m/e: 872 (M+H)⁺.

Example 11 Boc-Trp-DLvsfCbz ιlff2fH TazfAsp)]Pea In a procedure similar to Example 2, the product of Example 10 (230mg, 0.26mmol) was saponified in a mixture of THF (10ml) and H₂0 (5ml) at ambient temperature by addi¬ tion of IN NaOH (0.66ml, 0.66mmol) followed by stirring for 1 hour. The reaction was acidified, extracted and the product was isolated in essentially t e sane manner as in s Example 2 to yield the title compound as a white solid after drying under high vacuum; yield lOOmg (0.128mmol, 48.4%), mp 75-78°C. MS (FAB) m/e: 782 (M+H)⁺.

Example 12 Boc-Trτ DLvsιlr[2(ΗyrazfAspηPea 0

In a procedure similar to Example 3, the product of Example 10 (2.25g, 2.58mmol) was hydrogenated overnight in HOAc (70ml) using 10% Pd/C catalyst (0.675g). The product was isolated essentially by the method of Example 3, excluding the trituration with ether to yield the title compound as a pink foam, yield 2.14g. MS (FAB) m/e: 648 (M+H)⁺.

Example 13 Boc-Tφ-DLvsrTac')Φ[2fHyrazfAsp Pea

Using the procedure of Example 4, the product of Example 12, (334mg, 0.516mmol) in DMF (30ml) was reacted in the presence of NMM (447mg, 1.29mmol) with 2- methylphenyl isocyanate (68.7mg, 0.516mmol) for 1 hour. Purification by the method of Example 4 provided the title compound as a white powder, yield 212mg (0.271mmol, 52.6%); mp 102-105°C. MS (FAB) m/e: 779 (M+H)⁺.

Example 14

Boc-Ti?-DLvsf4Hcniljf2fHYrazfAsp)]Pea

Using the procedure of Example 4, the product of Example 12 (334mg, 0.516mmol) in DMF (30ml) was reacted in the presence of NMM (447mg, 1.29mmol) with 4- hydroxycirinamic acid N-hydroxysuccinimide ester (0.135g, 0.516mmol) overnight. Purifi¬ cation by the method of Example 4 provided the title compound as a white powder, yield 180mg (0.227mmol, 44.0%), mp 117-120°C. MS (FAB) m/e: 794 (M+H)⁺. Example 15 Boc-Tφ-DLvsrPac')ιlr[2rH)TazfAsp )]Pea

Using the procedure of Example 4, the predict of Example 12 (334mg, 0.516mmol) was s reacted with phenyl isocyanate (61.5mg, 0.516mmol) for 1 hour. Purification by the method of Example 4 provided the title compound as a white powder, yield 198mg (0.258mmol, 50.0%), mp 105-108°C. MS (FAB) m/e: 767 (M+H)⁺.

Example 16 ιo Boc-Trp-DLvsfTosU[2fH)TazrAsp)lPea

Using the procedure of Example 4, the product of Example 12 (334mg, 0.516mmol) was reacted with (2-methylphenyl)sulphonyl chloride (0.0984mg, 0.516mmol) for 2 hours. Purification by the method of Example 4 provided the title compound as a white pow- i5 der, yield 84mg (0.105mmol, 20.3%), mp 86-91°C. MS (FAB) m/e: 802 (M+H)⁺.

Intermediate 8 H-DAsprOBnVOMe

0 In a preparation similar to that used for Intermediate 1, Boc-DAsp(OBn)-OH (17.3g, 0.0535mol) was reacted with thionyl chloride in methanol and the Boc group removed to yield the title compound in several crops; combined yield 12.2g (0.0518mol. 96.6%). MS (CI) m/e: 238 (M+H)⁺.

5 Intermediate 9

Boc-LvsfCbz DAspfOBnVOMe

In a procedure similar to that used for Intermediate 2. Boc-Lys(Cbz)-OH (20.7g, 0.0543mol) was dissolved in THF (800ml) below 5°C followed by addition of DIEA 0 (lO.Og, 0.0776mol) and pivaloyl chloride (6.55g, 0.0543mol) followed by stirring for 1 hour. Intermediate 8 (12.3g, 0.0517mol) in THF (50ml) was added followed by warming to ambient temperature over 0.5 hour. The reaction mixture was concentrated, redissolved in EtOAc. extracted, purified by preparative HPLC. and vacuum dried in the same manner as in the preparation of Intermediate 2 to yield the title compound as an off-white foam, 11.73g (0.0196mol, 37.8%). MS (FAB) m/e: 600 (M+H)⁺.

Intermediate 10 Boc-LvsfCbz)Ur[CSNH]DAsp(OBnVOMe

In an improved procedure similar to that used for Intermediate 3, Intermediate 9 (7.60g, 0.0127mol) was converted to the thioamide in THF (312ml) using Lawesson's reagent (12.48g, 0.0179mol) added in one portion followed by warming to 42°C for 5 hours. The mixture was filtered through celite, concentrated and purified by preparative HPLC by essentially the same method as in Intermediate 3 to yield the title compound as a foam. 7.43g (0.0121mol. 95.0%), MS (FAB) m/e: 616 (M+H)⁺.

Intermediate 11 Boc-LvsfCbz',iir[2fHVrazfDAsp(OBn ]]Pea

Intermediate 10 (7.33g, 0.0119mol) was dissolved in 300ml dry THF and cooled to 5°C. To this solution was added Hg(OAc)₂ (4.18g, 0.013 lmol) and phenylethyl hydrazine (1.79g, 0.026mol) followed by stirring at ambient temperature for 1.5 hours. Additional Hg(OAc)₂ (1.18g, 0.0131mol) and phenylethyl hydrazine (1.79g, 0.0262mol) were added followed by stirring overnight at ambient temperature. The mixture was filtered through celite, concentrated, and the residue purified by preparative HPLC by essentially the same method as in Intermediate 4 to yield the title compound as a foam which was collected and dried under high vacuum at 40°C; yield 5.8g (8.46mmol, 71.0%). MS (FAB) m/e: 686 (M+H)⁺.

Example 17 Boc-Trp-LvsfCbz)ιlrf2fH)TazfDAsprθBnη]Pea

In a procedure similar to Example 1, Intermediate 11 (5.7g, 8.31mmol) in EtOAc was deprotected by addition to a solution of saturated HCl in EtOAc. After 1 hour the reaction was concentrate d under re duced pressure to yield H-Lys (Cbz)- ψ[2(H)Taz[DAsp(OBn)]]Pea as the HCl salt. Boc-Trp-OH (2.66g, 8.73mmol) in THF at 0-5°C was activated with DIEA (3.22g, 0.0249mol) and pivaloyl chloride (1.05g, 8.73mmol) by stirring for 0.5 hour followed by coupling to the above H-Lys(Cbz)- ψ[2(H)Taz[DAsp(OBn)]]Pea in THF at 0-5°C for 2 hours. The reaction mixture was concentrated, extracted and purified by preparative HPLC in essentially h^~ same man- s ner as Example 1 to yield the title compound as a hard foam after drying under high vacuum; yield 5.75g (6.59mmol, 79.4%); mp 125-128°C. MS (FAB) 872 (M+H)⁺.

Example 18 Boc-Trp-LvsrCbz )ilr[2rH )TazfDAsp 1Pea 0

In a procedure similar to Example 2, the product of Example 17 (460mg, 0.528mmol) was saponified in a mixture of THF (10ml) and H₂0 (5ml) at ambient temperature by addition of IN NaOH (1.32ml, 1.32mmol) followed by stirring for 1 hour. The reaction was acidified, extracted and the product was isolated in essentially the same manner as Example 2 to yield the title compound as a white solid after drying under high vacuum; yield 184mg (0.236mmol, 44.7%), mp 122-124°C. MS (FAB) m/e: 782 (M+H)⁺.

Example 19 Boc-Trp-Lvsιlr[2(ΗyrazfDAspηPea

In a procedure similar to Example 3. the product of Example 17 (2.61g, 2.99mmol) was hydrogenated overnight in HOAc (70ml) using 10% Pd/C catalyst (0.78g). The product was isolated essentially by the method of Example 3, including trituration with ether to yield after drying under high vacuum the title compound as a pink solid, yield 2.23g. MS (FAB) m/e: 648 (M+H)⁺.

Example 20 Boc-Trp-LvsfTac^ilr^rHYrazfDAspηPea

Using the procedure of Example 4. the product of Example 19 (334mg, 0.516mmol) in DMF (30ml) was reacted in the presence of NMM (299mg, 2.96mmol) with 2- methylphenyl isocyanate (68.7mg, 0.516mmol) for 1 hour. Purification by the method of Example 4 provided the title compound as a white powder, yield 188mg (0.241mmol, 46.7%), mp 103-106°C. MS (FAB) m/e: 782 (M+H)⁺.

Example 21 Boc-Trp-Lvsf4Hcnilr[2fHVrazfDAsp)1Pea

Using the procedure of Example 4, the product of Example 19 (384mg, 0.516mmol) in DMF (30ml) was reacted in the presence of NMM (346mg, 3.42mmol) with 4- hydroxycinnamic acid N-hydroxysuccinimide ester (0.155g, 0.594mmol) overnight. Purifi- cation by the method of Example 4 provided the title compound as a white powder, yield 73mg (0.092mmol, 15.4%), mp 116-119°C. MS (FAB) m/e: 794 (M+H)⁺.

Example 22 Boc-Trp-LvsfPac^refHlTazrDAspΗPea

Using the procedure of Example 4, the product of Example 19 (334mg, 0.516mmol) was reacted in the presence of NMM (299mg, 2.96mmol) with phenyl isocyanate (61.5mg, 0.516mmol) for 1 hour. Purification by the method of Example 4 provided the title compound as a white powder, yield 125mg (0.163mmol, 48.8%), mp 99-102°C. MS (FAB) m/e: 767 (M+H)⁺.

Example 23 Boc-τrp-LvsfTos r2(ΗϊrazfDAsp Pea

Using the procedure of Example 4, the product of Example 19 (334mg, 0.516mmol) was reacted in the presence of NMM (447mg, 1.29mmol) with (2-methylphenyl)sulphonyl chloride (98.4mg, 0.516mmol) for 1 hour. Purification by the method of Example 4 provided the title compound as a white powder, yield 85 mg (0.106mmol, 20.5%), mp 93- 97°C. MS (FAB) m/e: 802 (M+H)⁺.

Intermediate 12 2S-α-[N.N^,-Bis-ft-butoxycarboπvQ-hvdrazino]benzenepropanamide The precursor to the title compound, 2S-α-[N,N'-bis-(t-butoxycarbonyl)hydrazino]benz- enepropanoic acid, was prepared as described by D A Evans et al in Tetrahedron, Vol 44, No 17, p5525. 1988. The amide was prepared by the mixed anhydride procedure in which the a id (3.5^, 9.31mmol) in THF (95ml) was cooled to 0°C, treated with DIEA s (2.41g, 18.6mmol) and pivaloyl chloride (1.25g, 1.04mmol), stirred for ,0.5 hour at 0-5°C, followed by addition of saturated NH₃ in ether (95ml) and warming to ambient tempera¬ ture over 2.5 hours. The reaction mixture was concentrated to a residue dissolved in EtOAc (150ml) and washed with IN KHS0₄ (50ml), saturated NaHC0₃ (50ml), satu¬ rated NaCl (50ml). The organic layer was dried over MgS0₄, filtered and concentrated o under reduced pressure to a residue (3.82g). This product was purified by preparative HPLC (one Prepak, solvent gradient 10-50% EtOAc in Hexanes over 1 hour, 60ml/min). Upon concentration the residue was dried under high vacuum overnight to yield the title compound as a white foam, yield 3.42g, (9.01mmol, 96.7%). MS (CI) m/e: 380 (M+H)⁺.

Intermediate 13

2S-α-hvdrazino-benzenepropanamide hvdrochloride

Ethyl acetate (200ml) was saturated with HCl gas below 5°C and added to Intermediate 12 (3.40g, 8.96mmol) followed by stirring to ambient temperature over 1 hour. This solution was concentrated under reduced pressure, reconstituted with EtOAc (20ml) and reconcentrated. The resulting solid was slurried in EtOAc and collected and dried under high vacuum overnight to yield the title compound as the hydrochloride salt, yield 1.67g, (7.74mmol, 86.4%). MS (CI) m/e: 180 (M+H)⁺.

Intermediate 14

Boc-LvsrCbz Ur[2fHYrazfAspfOBn ]1Phe-NH,

Intermediate 3 (2.46g, 4.00mmol) was dissolved in dry THF (100ml) to which was added DIEA (2.07g, lό.Ommol), Hg(OAc)₂ (1.27g, 4.0mmol) and Intermediate 13 (0.863g, 4.0mmol) followed by stirring at ambient temperature. After 4 hours the reaction was treated with additional Hg(OAc)₂ (0.64g, 2.0mmol) followed by stirring overnight. Addi¬ tions of Hg(OAc), (0.64g, 2.0mmol) and Intermediate 13 (86.3mg, 0.40mmol) were made followed by stirring for 1.5 hours. The mixture was then filtered through celite and concentrated in vacuo to yield a residue which was purified by preparative HPLC (two Prepaks, 60ml/min, solvent gradient 0-10% MeOH in CHC1₃ over 1 hour). Fractions containing the product were combined, concentrated and dried under reduced pressure to yield the title compound as a foam, yield 1.48g (2.03mmol, 50.7%) MS (FAB) m/e: 729 (M+H)⁺.

Example 24 Boc-T -LvsfCbz^[2fHVrazfAspfOBn iPhe-NH,

In a procedure similar to Example 1, Intermediate 14 (1.46, lOmmol) in EtOAc (35ml) was deprotected at 0-5°C by addition to a saturated solution of HCl in EtOAc (35ml). After 1 hour the reaction was concentrated under reduced pressure to yield H-Lys(Cbz)- ψ[2(H)Taz[Asp(OBn)]]Phe-NH₂ as the HCl salt. Boc-Trp-OH (0.64g, 5.0mmol) was activated in THF (25ml) at 0-5°C with DIEA (l.lόg, δ.Ommol) and pivaloyl chloride (0.25g, 2.10mol) followed by stirring for 0.5 hour followed by treatment with the above H-Lys(Cbz)ψ[2(H)Taz[Asp(OBn)]]Phe-NH₂ in THF (25ml) at 0-5°C for 1 hour. The reaction mixture was concentrated, extracted and purified by preparative HPLC in essentially the same manner as Example 1 to yield the product as a foam after drying under high vacuum, yield 1.49g (1.63mmol, 81.4%), mp 92-95°C. MS (FAB) m/e: 915 (M+H)⁺.

Example 25 Boc-Trp-Lvsfα^il^fHlTazfAspllPhe-NH,

In a procedure similar to Example 2, the product of Example 24 (200mg, 0.22mmol) was saponified in a mixture of THF (5ml) and H₂0 (2.5ml) at ambient temperature by addi-

^• tion of IN NaOH (0.33ml. 0.33mmol) followed by stirring for 1 hour. The reaction was acidified, extracted and the product was isolated in essentially the same manner as

Example 2 using only ether in this case to triturate and collect the product, yielding a white solid after drying under high vacuum, yield 144mg (0.175mmol. 79.5%), mp 150- 155°C. MS (FAB) m/e: 825 (M + H)⁺, 909 (M+Rb)⁺.

Example 26 Boc-Trp-Lvsτjrr2(ΗVrazfAspΗPhe-NH,

In a procedure similar to Example 3. the product of Example 24 (1.2g, 1.31mmol) was hydrogenated overnight in HOAc (50ml) using 10% Pd C catalyst (0.35g). The product 5 was isolated in essentially the same manner to Example 3, including trituration with ether, to yield after drying under high vacuum the title compound as a light pink solid, yield 0.845g (1.22mmol, 93.1%). MS (FAB) m/e: 691 (M+H)⁺, (contains for 6.0% AcOH, 1.4% H₂0).

ιo Example 27

Boc-Trp-LvslTac Hr[2rHTrazfAsp)]Phe-NH-,

Using the procedure of Example 4, the product of Example 26 (420mg, 0.608mmol)_, in DMF (45ml) was reacted in the presence of DIEA (162mg, 1.22mmol) with 2-methyl- i5 phenyl isocyanate (69.1mg, 0.520mmol) for 1 hour. Purification was achieved by the method of Example 4, with a solvent gradient of 60-70% MeOH in H₂0 over 1 hour. In this case the product was isolated by extraction of the concentrated aqueous phase with EtOAc (2x50ml) followed by drying over MgS0₄, filtering and concentrating under reduced pressure. Trituration and collection with ether provided the product as an off- 0 white powder, yield 210mg (0.255mmol, 41.9%), mp 105°C (softens), 173-175°C. MS (FAB) m/e: 824 (M+H)⁺.

Example 28 Boc-Trp-LvsfPac^ilr^rHlTazfAsp^Phe-NH-, 5

Using the procedure of Example 4, the product of Example 26 (398mg, 0.575mmol) in DMF (45ml) was reacted in the presence of DIEA (150mg, 1.15mmol) with phenyl isocyanate (54.8mg, 0.460mmol) for 1 hour. Purification by the method of Example 4 (solvent gradient 60-70% MeOH in H₂0), and collection of the solid produced during o initial concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 230mg (0.258mmol, 49.4%), mp 123°C (soften), 168-173°C. MS (FAB) m/e: 810 (M+H)⁺. Example 29 Boc-Trp-LvsfBac)ιlff2(Η^NiTazfAspηPhe-NH,

Using the procedure of Example 4, the product of Example 26 (80mg, O.l lόmmol) in DMF (10ml) was reacted in the presence of DIEA (30mg, 0.23 mmol) with benzyl iso¬ cyanate (14mg, 0.104mmol) for 2 hours. Purification by the method of Example 4 (sol¬ vent gradient 50-65% MeOH in H₂0), and collection of the solid produced during con¬ centration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 46mg (0.056mmol, 48.1%). MS (FAB) m/e: 825 (M+H)⁺.

Example 30 Boc-Trp-Lvsr4Hcnnj[2fHTrazfAsp Phe-NH-,

Using the procedure of Example 4, the product of Example 26 (lOOmg, 0.145mmol) in DMF (10ml) was reacted in the presence of DIEA (37.5 mg, 0.0290mmol) with 4-hyd- roxycinnamic acid N-hydroxysuccinimide ester (4Hci-Osu, 38mg, 0.145 mmol) for 3 hours. Additional DIEA (37.5mg, 0.0290mmol) and 4Hci-OSu (15mg, 0.057mmol) was added followed by stirring for 2 hours. Purification by the method of Example 4 (solvent gradient 50-65% MeOH in H₂0), and collection of the solid produced during concentra¬ tion of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 58.3mg (0.070mmol, 48.0%). MS (FAB) m/e: 837 (M+H)⁺.

Example 31

Boc-T -LvsfHpp^[2fHTrazfAsp Phe-NH,

Using the procedure of Example 4, the product of Example 26 (80mg, O.llόmmol) in DMF (10ml) was reacted in the presence of DIEA (30mg, 0.0232mmol) with 3-(4-hyd- roxyphenyl)propanoic acid N-hydroxysuccinimide ester (Hpp-OSu, 27.4mg, 0.104mmol) for 3 hours. Additional DIEA (30mg, 0.0232mmol) and Hpp-OSu (14mg, 0.1052mmol) were added followed by stirring for 2 hours. Purification by the method of Example 4 (solvent gradient 50-65% MeOH in H₂0), and collection of the solid produced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 38.4mg (0.046mmol, 39.5%). MS (FAB) m/e: 839 (M+H)⁺.

s Intermediate 15

Boc-DLvsrCbz )ιif[2rH)Taz[AspfOBn ]]Phe-NH-,

The product of Intermediate 6 (3.08g, 5.00mmol) was dissolved in dry THF (200ml) to which was added DIEA (2.60g, 20.0mmol), Hg(OAc)₂ (1.60g, 5.0mmol) and Intermediate ιo 13 (1.08g, 5.0mmol) followed by stirring at ambient temperature for 5 hours. The mix¬ ture was then filtered through celite rinsing with THF, and concentrated in vacuo to yield a residue which was purified by preparative HPLC (two Prepaks, 60ml min, solvent gradient 0-10% MeOH in CHC1₃ over 1 hour). Fractions containing the product were combined, concentrated and dried under reduced pressure to yield the title compound is as a foam, yield 1.84g (2.52mmol, 50.5%). MS (FAB) m/e: 729 (M+H)⁺.

Example 32 Boc-Trp-DLvsrCbz^Ur^fHTTazfAspfOBnΗIPhe-NH,

0 In a procedure similar to Example 1, the product from Intermediate 15 ( 1.79g, 2.45mmol) in EtOAc (45ml) was deprotected at 0-5°C by addition to a saturated solution of HCl in EtOAc (45ml). After 1 hour the reaction was concentrated under reduced pressure, reconstituted with EtOAc and reconcentrated to yield H-DLys(Cbz)- ψ[2(H)Taz[Asp(OBn)]]Phe-NH₂ as the HCl salt. Boc-Trp-OH (0.783g, 2.57mmol) was s activated in THF (35ml) at 0-5°C with DIEA (l.llg, 8.57mmol) and pivaloyl chloride (0.3 lg, 2.57mmol) followed by stirring for 0.5 hour followed by treatment with a solution of H-DLys(Cbz)ψ[2(H)Taz[Asp(OBn)]]Phe-NH₂ in THF (35ml) at 0-5°C for 1 hour and warming to room temperature for 1 hour. The reaction mixture was concentrated, extracted and purified by preparative HPLC in essentially the same manner as Example υ 1 (solvent gradient 0-10% MeOH in CHC1₃) to yield the product as a foam after drying under high vacuum; yield 1.52g (l.όόmmol, 67.8%). MS (FAB) m/e: 915 (M+H)⁺.

Example 33 Boc-Trp-DLvsfCbz ιlrf2(ΗVrazfAsp Phe-NH,

In a procedure similar to Example 2, the product of Example 32 (lOOmg, 0.109mmol) was saponified in a mixture of THF (2.5ml) and H₂0 (1.25ml) at 0-5°C by addition of s IN NaOH (0.33ml, 0.33mmol) followed by stirring to ambient temperature for 1 hour. The reaction was acidified, extracted and the product isolated in essentially the same manner as Example 2 using only ether in this case to triturate and collect the product, yielding a white solid after drying under high vacuum, yield 70.3mg (0.085mmol, 78.2%). MS (FAB) m/e: 825 (M+H)⁺, 909 (M+Rb)⁺. 0

Example 34 Boc-Trp-DLvsιlrf2(ΗVraz(Asp Phe-NH-,

In a procedure similar to Example 3, the product of Example 32 (1.34g, 1.46mmol) was s hydrogenated overnight in HOAc (55ml) using 10% Pd/C catalyst (0.40g). The product was isolated in essentially the same manner to Example 3, including trituration with ether, to yield after drying under high vacuum the title compound as a light pink solid, yield 0.933g (1.35mmol, 92.5%). MS (FAB) m/e: 691 (M+H)⁺, (contains 8.0% AcOH, 0.9% H₂0).

Example 35 Boc-Trp-DLvsfTac^[2rHVrazfAsp)]Phe-NH.-

Using the procedure of Example 4, the product of Example 34 (350mg, 0.507mmol) in DMF (40ml) was reacted in the presence of DIEA (134mg, l.Olmmol) with 2-methyl- phenyl isocyanate (57.4mg, 0.431mmol) for 2 hours. Purification was achieved by the method of Example 4 (solvent gradient 55-70% MeOH in H₂0 over 1 hour) and collec¬ tion of the solid produced during concentration of the eluant followed by drying over¬ night at 40°C under vacuum provided the product as a white powder, yield 241mg (0.292mmol, 57.7%). MS (FAB) m/e: 824 (M+H)⁺.

Example 36 Boc-Trp-DLvsfPac ιlr[2(ΗyrazfAspηPhe-NH., Using the procedure of Example 4, the product of Example 34 (350mg, 0.507mmol) in DMF (40ml) was reacted in the presence of DIEA (131mg, l.Olmmol) with phenyl isocyanate (51.3mg, 0.507mmol) for 1 hour. Purification by the method of Example 4 (solvent gradient 55-70% MeOH in H₂0), and collection of the solid produced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 265mg (0.327mmol, 64.5%). MS (FAB) m/e: 810 (M+H)⁺.

Example 37 Boc-Tro-DLvsf4Hcnilr[2rHVrazrAsp^Phe-NH,

Using the procedure of Example 4, the product of Example 34 (175mg, 0.253mmol) in DMF (20ml) was reacted in the presence of DIEA (65.4mg, 0.506mmol) with 4-hydroxy- cinnamic acid N-hydroxysuccinimide ester (4Hci-OSu, 66.1mg, 0.145mmol) for 3 hours. Additional DIEA (65.4mg, 0.506mmol) and 4Hci-OSu (13.2mg, 0.051mmol) were added followed by stirring 2 hours. Purification by the method of Example 4 (solvent gradient 50-65% MeOH in H_zO), and collection of the solid produced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 164mg (0.195mmol, 77.1%. MS (FAB) m/e: 837 (M+H)⁺.

Example 38 H-Tπ LvsrTaclΦf2rHVrazfAspηPhe-NH,

The product from Example 27 (60.4mg, 0.073mmol) in EtOAc (4ml) was deprotected at 0-5°C by addition to a solution of saturated HCl in EtOAc (4ml). After 2 hours the reaction was concentrated under reduced pressure, reconstituted with EtOAc and reconcentrated to yield H-Trp-Lys(Tac)[2(H)Taz(Asp)]Phe-NH₂. The residue was dis¬ solved in THF/H₂0 [1:1] and purified by preparative HPLC in essentially the same man¬ ner as Example 4 (solvent gradient 50-60% MeOH in H₂0, containing no buffers, ove 1 hour). The eluant containing product was concentrated to remove the MeOH and the remaining solution was basifϊed with NH₃ gas and lyophilized under high vacuum to yield the product as a white powder: yield 25.1mg (0.0347mmol, 47.5%). MS (FAB) m/e: 724 (M+H)⁺. Example 39 H-Trp-LvsrPac^Ur rHTTazfAsp Phe-NH-,

The product from Example 28 (56.5mg, 0.070mmol) in EtOAc (4ml) was deprole ted s at 0-5°C by addition to a solution of saturated HCl in EtOAc (5ml). After 2 hours the reaction was concentrated under reduced pressure, reconstituted with EtOAc and reconcentrated to yield H-Trp-Lys(Pac)ψ[2(H)Taz(Asp)]Phe-NH₂.

The residue was dissolved in 1:1 THF/H₂0 and purified by preparative HPLC in essen- o tially the same manner as Example 4 (solvent gradient 50-60% MeOH in H₂0, contain¬ ing no buffers, over 1 hour). The eluant containing product was concentrated to remove the MeOH and the remaining solution was basified with NH₃ gas and lyophilized under high vacuum to yield the product as a white powder; yield 24.7mg (0.0348mmol, 49.7%).

MS (FAB) m/e: 710 (M+H)⁺. 5

Example 40 H-Trp-DLvsrTac)ιlf[2rH)TazfAsp)]Phe-NH-,

The product from Example 35 (50.0mg, O.Oόlmmol) in EtOAc (5ml) was deprotected at 0-5°C by addition to a solution of saturated HCl in EtOAc (5ml). After 2 hours the reaction was concentrated under reduced pressure, reconstituted with EtOAc and reconcentrated to yield H-Trp-DLys(Tac)[2(H)Taz(Asp)]Phe-NH2 as the HCl salt. The residue was dissolved in 1:1 THF/H₂0 and purified by preparative HPLC in essentially the same manner as Example 4 (solvent gradient 50-60% MeOH in H₂0, containing no buffers, over 1 hour). The eluant containing product was concentrated to remove the MeOH and the remaining solution was lyophilized under high vacuum to yield the prod¬ uct as a white powder; yield 23.7mg (0.0327mmol, 53.7%). MS (FAB) m/e: 724 (M+H)⁺.

Example 41

Bz-Trp-DLvs(Υac r 2(Η)TazfAsp Phe-NH, The product from Example 35 (90.0mg, 0.109mmol) in EtOAc (7ml) was deprotected at 0-5°C by addition to a solution of saturated HCl in EtOAc (7ml). After 2 hours the reaction was concentrated under reduced pressure, reconstituted with EtOAc and reconcentrated to yield H-Tφ-DLys(Tac)ψ[2(H)Taz(Aφ)]Phe-NH₂ as the HCl salt. The residue was dissolved in DMF (10ml) at 0°C and treated in the presence of DIEA (42.2mg, 0.327mmol) with benzoic anhydride (24.6mg, O.llOmol) for 2 hours. Concen¬ tration, purification by the method of Example 4 (solvent gradient 50-65% MeOH in H₂0) and collection of the solid produced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 61.4mg (0.0742mmol, 68.0%). MS (FAB) m/e: 828 (M+H)⁺.

Example 42 H-Trp-DLvsrPac^Urf2(Η)TazfAsp Phe-NH,

The product from Example 36 (50.0mg, 0.062mmol) in EtOAc (5ml) was deprotected at 0-5°C by addition to a solution of saturated HCl in EtOAc (5ml). After 2 hours the reaction was concentrated under reduced pressure, reconstituted with EtOAc and reconcentrated to yield H-Tφ-DLys(Pac)ψ[2(H)Taz(Asp)]Phe-NH₂ as the HCl salt. The residue was dissolved in 1:1 THF/H₂0 and purified by preparative HPLC in essentially the same manner as Example 4 (solvent gradient 50-60% MeOH in H₂0 containing no buffers, over 1 hour). The eluant containing product was concentrated to remove the MeOH and the remaining solution was lyophilized under high vacuum to yield the prod¬ uct as a white powder; yield 30.5mg (0.043mmol, 69.3%). MS (FAB) m/e: 710 (M+H)⁺.

Example 43

Bz-Trp-DLvs( ac')Urr2fH )TazfAsp)]Phe-NH,

The product from Example 36 (90.0mg, O.l llmmol) in EtOAc (7ml) was deprotected at 0-5°C by addition to a solution of saturated HCl in EtOAc (7ml). After 2 hours the reaction was concentrated under reduced pressure, reconstituted with EtOAc and reconcentrated to yield H-Trp-DLys(Pac)ψ[2(H)Taz(Asp)]Phe-NH₂ as the HCl salt. The residue was dissolved in DMF (10ml) at 0°C and treated in the presence of DIEA (43.0mg, 0.333mmol) with benzoic anhydride (25.1mg, O.lllmol) for 2 hours. Concen- tration, purification by the method of Example 4 (solvent gradient 50-75% MeOH in H₂0) and collection of the solid produced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 50.6mg (0.0742mmcl, 62.2%). MS (FAB) m/e: 814 (M+H)⁺.

Example 44 Bz-Trp-DLvs(Tac^[2(ΗyrazfAspηPea

The product from Example 13 (43.0mg, 0.055mmol) in EtOAc (5ml) was deprotected at 0-5°C by addition to a solution of saturated HCl in EtOAc (5ml). After 2 hours the reaction was concentrated under reduced pressure, reconstituted with EtOAc and reconcentrated to yield H-Tφ-DLys(Tac)[2(H)Taz(Asp)]Pea. The residue was dissolved in DMF (10ml) at 0°C and treated in the presence of DIEA (21.3mg, 0.165mmol) with benzoic anhydride (12.4mg, 0.055mol) for 2 hours. Concentration and purification by the method of Example 4 (solvent gradient 50-75% MeOH in H₂0). The eluant con¬ taining product was concentrated to remove the MeOH and the remaining solution was lyophilized under high vacuum providing the product as a white powder, yield 17.4mg (0.022mmol, 40.3%). MS (FAB) m/e: 785 (M+H)⁺.

Example 45

Boc-Tφ-Lvsf4HciSE)ιH2(Η')TazfAspηPhe-NH-,

The product of Example 30 (450mg, 0.540mmol) in dry pyridine (45ml) and dry DMF (45ml) was treated with sulphur trioxide-pyridine complex (1.72g, 10.8mmol) and heated to 40°C for 2 hours, monitoring the reaction by HPLC. The reaction was quenched by pouring into 5% NH₄OH (100ml) at 0-5°C, concentrated to a slurry and filtered using additional DMF (25ml), basified again with 5% NH₄OH (25ml), and concentrated to dryness. The product was dissolved in minimal THF/H₂0 [1:1] (l-2ml) and purified by reverse-phase HPLC similarly to Example 4 (using two 4x10cm. microC-18 bondapak columns in series, 30ml/min, solvent gradient 30-50% MeOH in H₂0 containing 0.1% NH₄OAc over 1.0 hour). Isolation of the sample by concentration of the eluant to half volume followed by repetitively (three times) freeze drying, with dissolution of the residue in H₂0 slightly basified each time with NH₃, produced the product as a white, fluffy lyophilized solid, yield 285mg (0.305mmol, 56.5%). MS (ES) m/e: 915 (M-H)\

Example 46 s Boc-Trp-DLvsf4HciSE )ilrr2fH )TazfAsp ]Phe-NH,

The product of Example 37 (352mg, 0.421mmol) in dry pyridine (30ml) and dry DMF (30ml) was treated with sulphur trioxide-pyridine complex (l.OOg, 6.31mmol) and heated to 40°C overnight, monitoring the reaction by HPLC. The reaction was quenched at 0- o 5°C with 5% NH₄OH (100 ml), filtered and concentrated using the method in Example 45. The resultant product was dissolved in minimal 1:1 THF-H₂0 (l-2ml) and purified by reverse-phase HPLC similarly to Example 45 (solvent gradient 30-50% MeOH in H₂0 containing 0.1 % NH₄OAc). Isolation of the sample by concentration and lyophilization using the method of Example 45 produced the product as a white, fluffy lyophilized solid, yield 212mg (0.227mmol, 53.9%). MS (ES) m/e: 915 (M-H)^'.

Intermediate 17 H-Tφ-DLvsfCbz')Ur[2(Η )Taz[Asp(OBn l|Phe-NH-,

The product of Example 32 (1.05g, 1.15 mmol) in EtOAc (50ml) was deprotected in the presence of anisole (373mg, 3.45 mmol) at 0-5°C by addition to a solution of saturated HCl in EtOAc (50ml). After 2 hours the reaction was concentrated under reduced pressure, reconstituted with EtOAc and reconcentrated to yield the title compound as the HCl salt, yield 964mg (1.14mmol, 99%). MS (ES) m/e: 815 (M+H)⁺.

Intermediate 18 , Method A Ipoc-Trp-DLvsfCbz ι]rf2(Η')Taz[Asp(OBn^N)]]Phe-NH.-

The product of intermediate 17 (892mg, 1.05mmol) was dissolved in DMF (100ml) at 0°C and treated in the presence of DIEA (270 mg, 2. lOmmol) with N-(isopropyioxy- carbonyloxy)succinimide (Ipoc-OSu, 221mg, l.lOmol) for 2 hours. The reaction mixture was concentrated, extracted and purified by preparative HPLC in essentially the same manner as Example 1 (solvent gradient 0-10% MeOH in CHC1₃) to yield the product as an off white foam after drying under high vacuum; yield 890mg (0.988mmol, 94%). MS (ES) m/e: 901 (M+H)⁺.

Intermediate 18 . Method B s Ipoc-Trp-DLvsfC^zW2fHVrazfAsp(OBn)]]Phe-NH-,

In a procedure similar to Example 32, Ipoc-Trp-OH (1.70g, 5.85mmol, prepared from H-Tφ-OH and N-(isopropyloxycarbonyloxy)succinimide by standard means) was dis¬ solved in THF (100ml) and treated at 0-5°C with DIEA (1.78g. 13.3mmol) and pivaloyl o chloride (640mg, 5.32mmol) followed by stirring for 30 minutes. The intermediate in Example 32, H-DLys(Cbz)ψ[2(H)Taz[Asp(OBn)]]Phe HCl salt (3.54g, 5.32mmol) was added followed by stirring at ambient temperature for 2 hours. The reaction mixture was concentrated, extracted and purified by preparative HPLC in essentially the same manner as Example 1 (solvent gradient 0-10% MeOH in CHC1₃) to yield the product as a foam after drying under high vacuum; yield 3.92g (4.35mmol, 81.8%). MS (ES) m/e: 899 (M-H)\

Intermediate 19. Method A Ipoc-Trp-DLvsilr^fHϊrazfAspηPhe-NH-,

In a procedure similar to Example 3, the product of Intermediate 18, Method A (850mg, 0.94mmol) was hydrogenated overnight in HOAc ( 100ml) using 10% Pd/C catalyst (0.25g). The product was isolated in a similar manner to Example 3. including trituration with ether, to yield after drying under high vacuum the title compound as a light pink residue, yield 850 mg. MS (ES) m/e: 677 (M+H)⁺.

Intermediate 19. Method B Ipoc-Trp-DLvsUrf2(ΗϊrazfAsp Phe-NH.,

In a procedure similar to Example 3, the compound of Intermediate 18. Method B (3.78g, 4.20mmol) was hydrogenated for 6 hours in HOAc (200ml) using 10% Pd/C catalyst (0.25g). The product was isolated by trituration by stirring in ether (50ml) followed by concentration and repeated trituration and collection from ether to yield after drying under high vacuum the title compound as a light pink residue, yield 2.88g, (4.20 mmol). MS (ES) m/e: 677 (M+H)⁺.

Example 47 s Ipoc-Trp-DLvsr4Hcn!irf2fH1TazrAsp^Phe-NH.,

Using the procedure of Example 4, the product of Intermediate 19, Method A, (0.94mmol) in DMF (75ml) was reacted in the presence of NMM (720mg, 7.05mmol) with 4-hydroxycinnamic acid N-hydroxysuccinimide ester (4Hci-OSu, 260mg, l.OOmmol) o overnight. Purification by reverse-phase HPLC similarly to Example 4 using two 4x10cm, microC-18 bondapak columns in series (30ml/min, solvent gradient 50-70% MeOH in H₂0 over one hour buffered with 0.2% TEA and 0.2% HOAc) and collection of the solid produced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 408mg s (0.495mmol, 52.7%). MS (ES) m/e: 823 (M+H)⁺.

Example 48 Ipoc-Trp-DLvsr4HciSEW2rHyTazfAspηPhe-NH,

0 Using the procedure of Example 45, the product of Example 47 (355 mg, 0.431 mmol) in dry pyridine (40ml) and dry DMF (40ml) was treated with sulphur trioxide-pyridine complex (1.37g, 8.36mmol) and heated to 40°C overnight, monitoring the reaction by HPLC. The reaction was quenched, filtered and concentrated using the method of Example 45. The resultant product was dissolved in minimal THF/H₂0 [1:1] (l-2ml) s and purified by reverse-phase HPLC similarly to Example 45 (solvent gradient 30-50% MeOH in H₂0 containing 0.1% NH₄OAc). Isolation of the sample by concentration and lyophilization by the method of Example 45 produced the product as a white, fluffy lyophilized solid, yield 250mg (0.272mmol, 63.1%). MS (ES) m/e: 901 (M-H)\ 903 (M+H)⁺.

Example 49 Boc-Tφ-LvsfDhcnil^fHlTazfAsp Phe-NH-, Using the procedure of Example 4, the product of Example 26, (220mg, 0.325mmol) in DMF (25ml) was reacted in the presence of NMM (123mg, 1.63mmol) with 3,4-dihyd- roxycinnamic acid N-hydroxysuccinimide ester (Dhci-OSu, lOOmg, 0.361mmol) overnight. Purification by reversed-phase HPLC by the method of Example 47 (solvent gradient 50-55% MeOH in H₂0), and collection of the solid produced during concentration of the eluant followed by vacuum drying overnight at 40°C provided the product as a white powder, yield 115mg (0.135mmol, 41.5%). MS (ES) m/e: 851 (M-H)\

Example 50 Boc-Trp-DLvs hcnι]j[2(Tr.TazfAspηPhe-NH.,

Using the procedure of Example 4, the product of Example 34, (220mg, 0.325mmol) in DMF (25ml) was reacted in the presence of NMM (123mg, 1.63mmol) with 3,4-dihyd- roxycinnamic acid N-hydroxysuccinimide ester (Dhci-OSu, lOOmg, 0.361mmol) overnight, Purification by reverse-phase HPLC by the method of Example 47 (solvent gradient 50- 55% MeOH in H₂0, purified twice), and collection of the solid produced during concen¬ tration of the eluant followed by vacuum drying overnight at 40°C provided the product as a white powder, yield 55mg (0.064mmol, 19.7%). MS (ES) m/e: 851 (M-H)\

Example 51

Boc-Trp-DLvsrCnilj[2fHVrazfAsp)]Phe-NH-,

Using the procedure of Example 4, the product of Example 34, (200mg, 0.290mmol) in DMF (20ml) was reacted in the presence of DIEA (94mg, 0.724mmol) with cinnamoyl chloride (43.5mg, 0.26mmol) for 20 minutes. Purification by reverse-phase HPLC by the method of Example 47 (solvent gradient 50-70% MeOH in H₂0) and collection of the solid produced during concentration of the eluant followed by vacuum drying overnight at 40°C provided the product as a white powder, yield 154mg (0.187mmol, 65.0%). MS (ES) m/e: 819 (M-H)^", 821 (M+H)⁺.

Example 52 Boc-Trp-DLvsf2-Npc)τι;[2fHVrazfAsp)lPhe-NH, Using the procedure of Example 4, the product of Example 34, (200mg, 0.290mmol) in DMF (20ml) was reacted in the presence of DIEA (75mg, 0.580mmol) with 2-naphthoic acid N-hydroxysuccinimide ester (Np-OSu, 86.2mg, 0.320mmol) overnight. Purification by reverse-phase HPLC by the method of Example 47 (solvent gradient 50-70% MeOH in H₂0) and collection of the solid produced during concentration of the eluant followed by vacuum drying overnight at 40°C provided the product as a white powder, yield 176mg (0.215mmol, 74.0%). MS (ES) m/e: 845 (M+H)⁺.

Example 53 Boc-Trp-DLvsfHpp)ιlj[2rHyrazfAsp Phe-NH.,

Using the procedure of Example 4, the product of Example 34, (500mg, 0.724mmol) in DMF (50ml) was reacted in the presence of DIEA (187mg, 1.45mmol) with 3-(4-hyd- roxyphenyl)propanoic acid N-hydroxysuccinimide ester (Hpp-OSu, 195mg, 0.724mmol) overnight. Purification by reverse-phase HPLC by the method of Example 47 (solvent gradient 50-70% MeOH in H₂0) and collection of the solid produced during concentra¬ tion of the eluant followed by vacuum drying overnight at 40°C provided the product as a white powder, yield 437mg (0.521mmol, 71.9%). MS (ES) m/e: 839 (M+H)⁺.

Example 54

Boc-Trp-DLvsfHppSE^Ur^rmTazfAsp^Phe-NH-,

Using the procedure of Example 45, the product of Example 53 (300mg, 0.358mmol) in dry pyridine (35ml) and dry DMF (35ml) was treated with sulphur trioxide-pyridine complex (1.14g, 7.15mmol) and heated to 40°C for 6 hours, monitoring the reaction by HPLC. The reaction was quenched, filtered and concentrated using the method of Example 45. The resultant product was dissolved in minimal 1:1 THF-H₂0 (l-2ml) and purified by reverse-phase HPLC similarly to Example 45 (solvent gradient 30-60% MeOH in H₂0 containing 0.1% NH₄OAc). Isolation of the sample by concentration and lyophilization using the method of Example 45 produced the product as a white, fluffy lyophilized solid, yield 264mg (0.292mmol, 81.5%). MS (ES) m/e: 917 (M-H)\

Example 55 Boc-Trp-DLvsfNcnιlr 2rH TazfAspΗPhe-NH-,

TBTU (408mg, 1.27mmol), HOBt (194mg, 1.27mmol) and 4-nitrocinnamic acid (Nci, 246mg, 1.27mmol) in DMF (?0ml) followed by stirring at ambient temperature for 5 s minutes. To this reactive intermediate was added the product of Example 34, (783mg, 1.13mmol) in DMF (5ml). The entire reaction mixture was stirred for 2 hours monitor¬ ing by HPLC, then concentrated and purified by reverse-phase HPLC by the method of Example 47 (solvent gradient 50-70% MeOH in H₂0). Collection of the solid pro¬ duced during concentration of the eluant followed by vacuum drying overnight at 40°C ιo provided the product as a white powder, yield 556mg (0.642mmol, 56.8%). MS (ES) m/e: 864 (M-H)^", 866 (M+H)⁺.

Example 56 Boc-Trp-DLvsfAc ιlr[2fHyrazfAsp Phe-NH.,

The product of Example 55 (250mg, 0.289mmol) dissolved in a mixture of HOAc/H₂0 [75:30] (25ml) was treated with Zn dust (472mg, 7.23mmol) added slowly over 15 min¬ utes. The reaction mixture was stirred for 0.5 hours monitoring by HPLC, then was filtered, concentrated and purified by reverse-phase HPLC by the method of Example 20 47 (solvent gradient 50-75% MeOH in H₂0). Collection of the solid produced during concentration of the eluant followed by vacuum drying overnight at 40°C provided the product as a white powder, yield 181mg (0.216mmol, 75.0%). MS (ES) m/e: 836 (M+H)⁺, 736 (M-Boc)⁺.

25 Example 57

Boc-Trp-DLvsfAciSE^^fHYrazfAspηPhe-NH,

Using the procedure of Example 45, the product of Example 56 (100 mg, 0.120 mmol) in dry pyridine (10ml) and dry DMF (10ml) was treated with sulphur trioxide-pyridine 3o complex (191mg, 1.20mmol) and heated to 40°C for 2 hours, monitoring the reaction by HPLC. Additional sulphur trioxide-pyridine complex (95mg, 0.60mmol) was added followed by stirring for 4 hours. The reaction was quenched, filtered and concentrated using the method of Example 45. The resultant product was dissolved in minimal TΗF/Η₂0 [1:1] (l-2ml) and purified by reverse-phase HPLC similarly to Example 45 (solvent gradient 30-65% MeOH in H₂0 containing 0.1% NH₄OAc). Isolation of the sample by concentration and lyophilization using the method of Example 45 produced the product as a white, fluffy lyophilized solid, yield 53mg (0.0567mmol, 47.0%). MS s (ES) m/e: 914 (M-H)\

Example 58 Boc-Trp-DLvsf3Hcnιlff2rHYrazfAspηPhe-NH-,

Using a procedure similar to Example 55, the product of Example 34 (400mg, 0.579mmol) in DMF (4ml) was added to the reactive intermediate prepared by addition of TBTU (223mg, 0.695mmol) to a solution of HOSu (80mg, 0.695mmol), 3-hydroxy- cinnamic acid (3Hci, 114mg, 0.685mmol) and DIEA, (187mg, 0.357 mmol) in DMF (1.0ml) with stirring at ambient temperature for 5 minutes. The entire reaction mixture was stirred 2 hours, monitoring by HPLC, then concentrated. Purification by the method of Example 47 (solvent gradient 50-70% MeOH in H₂0), and collection of the solid pro¬ duced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 304mg (0.364mmol, 62.8%). MS (ES) m/e: 835 (M-H)\

Example 59 Boc-Trp-DLvsf3HciSE)Ur[2fHYrazfAsp)lPhe-NH,

Using the procedure of Example 45, the product of Example 58 (195mg, 0.233mmol) in dry pyridine (20ml) and dry DMF (20ml) was treated with sulphur trioxide-pyridine complex (742mg, 4.66mmol) and heated to 40°C for 4 hours monitoring the reaction by HPLC. The reaction was quenched, filtered and concentrated using the method of Example 45. The resultant product was dissolved in minimal THF/H₂0 [1:1] (l-2ml) and purified by reverse-phase HPLC similarly to Example 45 (solvent gradient 30-65% MeOH in H₂0 containing 0.1% NH OAc). Isolation of the sample by concentration and lyophilization using the method of Example 45 produced the product as a white, fluffy lyophilized solid, yield lόlmg (0.172mmol, 74.0%). MS (ES) m/e: 915 (M-H)^'. Example 60 Ipoc-Tφ-DLvsfCnι.j[2fHyrazfAspΗPhe-NH,

Using the procedure of Example 4, the title compound ot Intermediate 19, (300mg, 5 0.443mmol) in DMF (30ml) was reacted in the presence of DIEA (140mg, l.llmmol) with cinnamoyl chloride (66.4mg, 0.399mol) for 20 minutes. Purification by reverse-phase HPLC by the method of Example 47 (solvent gradient 50-70% MeOH in H_zO) and collection of the solid produced during concentration of the eluant followed by vacuum drying overnight at 40°C provided the product as a white powder, yield 129mg o (O.lόOmmol, 36.2%). MS (ES) m/e: 805 (M-H)\

Intermediate 20 3-f2-IndoleVpropanoyl-LvsfCbz)ιlj[2fHyraz[AspfOBnηiPhe-NH--

s In a procedure analogous to Intermediate 18, Method B, 3-(2-Indole)-propanoic acid (68.1mg, 0.36mmol was condensed with the intermediate from Example 24, H-Lys(Cbz)- t[2(H)Taz[Asp(OBn)]]Phe-NH₂HCl salt (0.25g, 0.34mmol) and purified by preparative HPLC in essentially the same manner as Example 1 (solvent gradient 0-5% MeOH in CHC1₃) to yield the product as a foam after drying under high vacuum; yield 145g o (0.181mmol, 50.3%). MS (ES) m/e: 800 (M+H)⁺.

Intermediate 21 3-r2-IndoleVpropanoyl-Lvsτlr[2rH^s)TazrAsp Phe-NH-,

5 Hydrogenation of the product of Intermediate 20 (140mg, 0.175mmol) by the method of Example 19 afforded the product as a pink solid after trituration and collection from ether, yield 123mg. MS (ES) m/e: 576 (M+H)⁺.

Example 61 0 3-f2-IndoleVpropanoyl-Lvsr4Hcnιlrf2rHϊrazfAsp 1Phe-NH-,

Using the procedure of Example 4, the product of Intermediate 21 (123mg, 0.214mmol) in DMF (10ml) was reacted in the presence of DIEA (l lOmg, 0.860mmol) with 4-hyd- roxycinnamic acid N-hydroxysuccinimide ester (4Hci-OSu, 56mg, 0.214mmol) overnight. Purification by the method of Example 47 (solvent gradient 50-65% MeOH in H₂0), and collection of the solid produced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as white powder, yield 55mg (0.076mmol, 35.0%). MS (ES) m/e: 722 (M+H)⁺.

Intermediate 22 3-r2-IndoleVpropanoyl-DLvsrCbz^N) lf[2fH )TazfAspfOBn ]Phe-NH-,

In a procedure analogous to Intermediate 18, Method B, 3-(2-Indole)-propanoic acid (0.39g, 2.07mmol) was condensed with the intermediate from Example 32, H- DLys(Cbz)ψ[2(H)Taz[Asp(OBn)]]Phe ^■ HCl salt (1.25g, 1.88mmol) and purified by preparative HPLC in essentially the same manner as Example 1 (solvent gradient 0-5% MeOH in CHC1₃) to yield the product as a foam after drying under high vacuum; yield 0.94g (1.17mmol, 62.5%). MS (ES) m/e: 800 (M+H)⁺.

Intermediate 23 3-f2-IndoleVpropanoyl-DLvsilr[2fHYrazfAsp)]Prie-NH.,

Hydrogenation of the product of Intermediate 22 (940mg, 1.175mmol) by the method of Intermediate 19 afforded the product as a pink solid after trituration and collection from ether, yield 610mg (l.Oόmmol, 90.5%). MS (ES) m/e: 576 (M+H)⁺.

Example 62 3-f2-Indoleypropanoyl-DLvsf4HcnιH2fHyrazfAspηPhe-NH,

Using the procedure of Example 58, the product of Intermediate 23 (600mg, 1.04mmol) in DMF (10ml) was added to the reactive intermediate prepared by addition of TBTU (369mg, 1.15mmol) to a solution of HOSu (132mg, 1.15mmol), 4-hydroxycinnamic acid (4Hci, 189mg, 1.15mmol) and DIEA (336mg, 2.60 mmol) in DMF (10ml) at 10°C with stirring for 5 minutes. The entire reaction mixture was. stirred at ambient temperature 1 hour, monitoring by HPLC, then concentrated. Purification by the method of Example 47 (solvent gradient 50-70% MeOH in H₂0). and collection of the solid produced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a light yellow powder, yield 146mg (0.202mmol, 19.4%). MS (ES) m/e: 722 (M+H)⁺.

s Intermediate 24

Eoc-Tφ-DLvsrCbz^[2rH )Taz[AsprθBnηiPhe-NH-,

In a procedure analogous to Intermediate 18, Method B, Eoc-Trp-OH (460mg, 1.65mmol, prepared from H-Trp-OH and N-(ethyloxycarbonyloxy)succinimide by stan- o dard means) was condensed with the intermediate from Example 32, H-DLys(Cbz)- ψ[2(H)Taz[Asp(OBn)]]Phe-NH₂ΗCl salt (l.OOg, 1.50mmol) and purified by preparative HPLC in essentially the same manner as Example 1 (solvent gradient 0-5% MeOH in CHC1₃) to yield the product as a foam after drying under high vacuum; yield 750mg (0.845mmol, 56.4%). MS (ES) m/e: 887 (M+H)⁺. 5

Intermediate 25 Eoc-Trp-DLvsUr[2(Η)TazrAspηPhe-NH-,

Hydrogenation of the product of Intermediate 24 (750mg, 0.845mmol) by the method of Example 19 afforded the product as a pink solid after trituration and collection from ether, yield 610mg. MS (ES) m/e: 663 (M+H)⁺.

Example 63 Eoc-Trp-DLvsr4Hcnιlf[2(Η)TazfAspηPhe-NH,

Using the procedure of Example 58, the product of Intermediate 25 (500mg, 0.7544mmol) was added to the reactive intermediate prepared by addition of TBTU (267mg, 0.830mmol) to a solution of HOSu (95.5mg, 0.830mmol), 4-hydroxycinnamic acid (4Hci, 136mg, 0.830mmol) and DIEA, (244mg, 1.89 mmol) in DMF (10ml) at 100°C . with stirring for 5 minutes. The entire reaction mixture was stirred for 2 hours at ambi¬ ent temperature, monitoring by HPLC, then concentrated. Purification by the method of Example 47 (solvent gradient 50-70% MeOH in H₂0), and collection of the solid pro¬ duced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 227mg (0.280mmol, 37%). MS (ES) m/e: 807 (M+H)⁺.

Intermediate 26 Moc-Tφ-DLvsrCbz^[2rH^<)Taz[AsprθBn'mPhe-NH,

In a procedure similar to Example 55, Moc-Tφ-OH (433mg, 1.65mmol, prepared from H-Trp-OH and N-(methyloxycarbonyloxy)succinimide by standard means) was con¬ densed by activation in DMF (25ml) with TBTU (530mg, 1.65mmol) and HOBt (253mg, 1.65mmol) followed by addition of the intermediate in Example 32, H-DLys(Cbz)- ψ[2(H)Taz[Asp(OBn)]]Phe HCl salt (l.OOg, 1.50mmol). The reaction mixture was con¬ centrated, extracted and purified by preparative HPLC in essentially the same manner as Example 1 (solvent gradient 0-5% MeOH in CHC1₃) to yield the product as a foam after drying under high vacuum; yield 1.20g (1.37mmol, 91.6%). MS (ES) m/e: 873 (M+H)⁺.

Intermediate 27 Moc-Trp-DLvsilr^rH^TazfAspηPhe-NH,

Hydrogenation of the product of Intermediate 26 (1.20g, 0.845mmol) by the method of Example 19 afforded the product as a light pink solid after trituration and collection from ether, yield 0.96 g. MS (ES) m/e: 649 (M+H)⁺.

Example 64 Moc-Tφ-DLvsr4Hc τlr[2fHTrazfAsp 1Phe-NH.,

Using the procedure of Example 47, the product of Intermediate 27, (600mg, 0.925m- mol) in DMF (50ml) was reacted in the presence of DIEA (300mg, 2.31mmol) with 4- hydroxycinnamic acid N-hydroxysuccinimide ester (4Hci-OSu, 266mg, 1.02mmol) over- night monitoring by HPLC. Concentration and purification by reverse-phase HPLC by the method of Example 45 (solvent gradient 50-60% MeOH in H₂0), and isolation of the sample by concentration and lyophilization using the method of Example 45 pro- vided the product as a white powder, yield 405mg (0.509mmol, 55.1%). MS (ES) m/e: 795 (M+H)⁺.

Example 65 s Moc-Tφ-DLvsf4HciSEW2(ΗVTazfAsp)1Phe-NH,

Using the procedure of Example 45, the product of Example 64 (200mg, 0.252mmol) in dry pyridine (25ml) and dry DMF (25ml) was treated with sulphur trioxide-pyridine complex (800mg, 5.03mmol) and heated to 40°C for 5 hours monitoring the reaction by o HPLC. The reaction was quenched, filtered and concentrated using the method of Example 45. The resultant product was dissolved in minimal THF/H₂0 [1:1] (l-2ml) and purified by reverse-phase HPLC similarly to Example 45 (solvent gradient 30-50% MeOH in H₂0 containing 0.1% NH₄OAc). Isolation of the sample by concentration and lyophilization by the method of Example 45 produced the product as a white, fluffy s lyophilized solid, yield 204mg (0.228mmol, 90.4%). MS (ES) m/e: 873 (M-H)^'.

Intermediate 28 Ival-Trp-DLvsrCbz)τlr[2fH )Taz[AspfOBπ ]Phe-NH-,

o In a procedure analogous to Intermediate 26, Ival-Tφ-OH (0.48g, 1.65mmol, prepared from H-Trp-OH and isovaleryl chloride by standard means) was condensed with the intermediate from Example 32, H-DLys(Cbz)ψ[2(H)Taz[Asp(OBn)]]Phe ^■ HCl salt (l.OOg, 1.50mmol) and purified by preparative HPLC in essentially the same manner as Example 1 (solvent gradient 0-5% MeOH in CHC1₃) to yield the product as a foam 5 after drying under high vacuum; yield 0.97g (1.08mmol, 72.0%). MS (ES) m/e: 899 (M+H)⁺.

Intermediate 29 Ival-Trp-DLvsτlr[2fHTrazfAsp Phe-NH-- 0

Hydrogenation of the product of Intermediate 28 (0.95g, 1.05mmol) by the method of Example 19 afforded the product as a pink solid after trituration and collection from ether, yield 0.77g. MS (ES) m/e: 675 (M+H)⁺. Example 66 Ival-Trp-DLvsr4Hcnιljf2fHTrazfAsp ]Phe-NH,

Using the procedure of Example 47, the product of Intermediate 29, (700mg, 1.04mmol) 5 in DMF (60ml) was reacted in the presence of DIEA (340mg, 2.60mmol) with 4-hyd- roxycinnamic acid N-hydroxysuccinimide ester (4Hci-OSu, 300mg, 1.14mmol) overnight monitoring by HPLC. Concentration and purification by reverse-phase HPLC by the method of Example 47 (solvent gradient 50-70% MeOH in H₂0), and collection of the solid produced during concentration of the eluant followed by drying overnight at 40°C ιo under vacuum provided the product as a white powder, yield 277mg (0.337mmol, 32.4%). MS (ES) m/e: 821 (M+H)⁺.

Example 67 Ival-Trp-DLvsr4HciSE^[2rHYrazfAspηPhe-NH,

IS

Using the procedure of Example 45, the product of Example 66 (148mg, 0.180mmol) in dry pyridine (20ml) and dry DMF (20ml) was treated with sulphur trioxide-pyridine complex (570mg, 3.60mmol) and heated to 40°C for 5 hours monitoring the reaction by HPLC. The reaction was quenched, filtered and concentrated using the method of 0 Example 45. The resultant product was dissolved in minimal THF/H₂0 [1:1] (l-2ml) and purified by reverse phase HPLC similarly to Example 45 (solvent gradient 30-50% MeOH in H_:0 containing 0.1% NH₄OAc). Isolation of the sample by concentration and lyophilization by the method of Example 45 produced the product as a white, fluffy lyophilized solid, yield 117mg (0.128mmol, 70.9%). MS (ES) m/e: 899 (M-H)\ 5

Example 68 Boc-Tφ-Lvs(Ηbc^ 2(l-nTazfAsp Phe-NH.,

Using the procedure of Example 4, the product of Example 26 (300mg, 0.434mmol) in o DMF (25ml) was reacted in the presence of NMM (174mg, 1.63mmol) with 4-(4'-hydrox- yphenyl)benzoic acid N-hydroxysuccinimide ester (Hbc-Osu, 203mg, 0.651mmol) over¬ night. Purification by the method of Example 47 (solvent gradient 50-75% MeOH in H₂0), and collection of the solid produced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 214mg (0.241mmol, 55.6%). MS (ES) m/e: 885 (M-H)\

Example 69 s Boc-Trp-LvsfHbcSE^N. r[2fH^s)TazfAsp')1Phe-NH.,

Using the procedure of Example 45, the product of Example 68 (HOmg, 0.124mmol) in dry pyridine (10ml) and dry DMF (10ml) was treated with sulphur trioxide-pyridine complex (0.391g, 3.72mmol) and heated to 40°C for 5 hours monitoring the reaction by o HPLC. The reaction was quenched, filtered and concentrated using the method of Example 45. The resultant product was dissolved in minimal THF/H₂0 [1:1] (l-2ml) and purified by reverse-phase HPLC similarly to Example 45 (solvent gradient 30-50% MeOH in H₂0 containing 0.1% NH₄OAc). Isolation of the sample by concentration and lyophilization by the method of Example 45 produced the product as a white, fluffy s lyophilized solid, yield 72.8mg (0.074mmol, 59.7%). MS (ES) m/e: 865 (M-H)\

Example 70 Boc-Trp-DLvsfHbc)ιlrf2fHTrazfAspηPhe-NH,

o Using the procedure of Example 4, the product of Example 34 (300mg, 0.434mmol) in DMF (25ml) was reacted in the presence of NMM (109mg, 1.08mmol) with 4-(4'-hydrox- yphenyl)benzoic acid N-hydroxysuccinimide ester (Hbc-Osu, 203mg, 0.651mmol) over¬ night. Purification by the method of Example 47 (solvent gradient 50-75% MeOH in H₂0), and collection of the solid produced during concentration of the eluant followed 5 by drying overnight at 40°C under vacuum provided the product as a white powder, yield 240mg (0.271mmol, 62.9%). MS (ES) m/e: 885 (M-H)\

Example 71 Boc-Trp-DLvsrHbcSE^s)τlr 2fH )Taz(Asp Phe-NH-, 0

Using the procedure of Example 45. the product of Example 70 (150mg, 0.170mmol) in dry pyridine (15ml) and dry DMF (15ml) was treated with sulphur trioxide-pyridine complex (0.540g, 3.39mmol) and heated to 40°C for 5 hours monitoring the reaction by HPLC. The reaction was quenched, filtered and concentrated using the method of Example 45. The resultant product was dissolved in minimal THF/H₂0 [1:1] (l-2ml) and purified by reverse-phase HPLC similarly to Example 45 (solvent gradient 30-60% MeOH in H₂0 containing 0.1% NH₄OAc). Isolation of the sample by concentration and s lyophilization by the method of Example 45 produced the product as a white, fluffy lyophilized solid, yield 117mg (0.118mmol, 69.7%). MS (ES) m/e: 865 (M-H)^'.

Example 72 Boc-Trp-LvsfNpc)Hr[2fHYrazfAsp Phe-NH-, 0

Using the procedure of Example 4, the product of Example 26 (lOOmg, 0.145mmol) in DMF (15ml) was reacted in the presence of NMM (36.7mg, 0.363mol) with naphthoic acid N-hydroxysuccinimide ester (Npc-OSu, 58.5mg, 0.217mmol) overnight. Purification by the method of Example 47 (solvent gradient 50-75% MeOH in H₂0), and collection of the solid produced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 76mg (0.090mmol, 62.0%). MS (ES) m/e: 843 (M-H)^".

Example 73 Boc-Trp-LvsfHnp)ιlj[2fHYrazfAspηPhe-NH-,

Using the procedure of Example 4, the product of Example 26 (300mg, 0.434mmol) in DMF (25ml) was reacted in the presence of NMM (109mg, 1.08mmol) with 6-hydroxy- naphthoic acid N-hydroxysuccinimide ester (Hnp-OSu, 149mg, 0.521mmol) overnight. Purification by the method of Example 47 (solvent gradient 50-75% MeOH in H₂0), and collection of the solid produced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 227mg (0.264mmol, 60.9%). MS (ES) m/e: 859 (M-H)\

Example 74

Boc-Trp-LvsrHnpSE^Ur[2fHyrazfAsp)]Phe-NH, Using the procedure of Example 45, the product of Example 73 (HOmg, 0.128mmol) in dry pyridine (10ml) and dry DMF (10ml) was treated with sulphur trioxide-pyridine complex (0.508g, 3.20mmol) and heated to 40°C for 7 hours monitoring the reaction by HPLC. The reaction was quenched, filtered and concentrated using the method of s Example 45. The resultant product was dissolved in minimal THF/H₂0 [1:1] (l-2ml) and purified by reverse-phase HPLC similarly to Example 45 (solvent gradient 50-75% MeOH in H₂0 containing 0.1% NH₄OAc). Isolation of the sample by concentration and lyophilization using the method of Example 45 produced the product as a white, fluffy lyophilized solid, yield 56.3mg (0.0588mmol, 46%). MS (ES) m/e: 939 (M-H)\

10

Example 75 Boc-Trp-DLvsfHnp)Urf2fHVrazfAsp^Phe-NH,

Using the procedure of Example 4, the product of Example 34 (300mg, 0.434mmol) iri is DMF (25ml) was reacted in the presence of NMM (149mg, 1.08mmol) with 6-hydroxy- naphthoic acid N-hydroxysuccinimide ester (Hnp-OSu, 149mg, 0.521mmol) overnight. Purification by the method of Example 47 (solvent gradient 50-75% MeOH in H₂0), and collection of the solid produced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 20 255mg (0.296mmol, 68.1%). MS (ES) m/e: 859 (M-H)^'.

Example 76 Boc-Trp-DLvsfHnpSE^^fHYTazfAspΗPhe-NH.,

25 Using the procedure of Example 45, the product of Example 75 (150mg, 0.174mmol) in dry pyridine (15ml) and dry DMF (15ml) was treated with sulphur trioxide-pyridine complex (0.83 lg, 5.22mmol) and heated to 40°C for 5 hours monitoring the reaction by HPLC. The reaction was quenched, filtered and concentrated using the method of Example 45. The resultant product was dissolved in minimal THF/H₂0 [1:1] (l-2ml_)

30 and purified by reverse-phase HPLC similarly to Example 45 (solvent gradient 50-75% MeOH in H₂0 containing 0.1% NH₄OAc). Isolation of the sample by concentration and lyophilization using the method of Example 45 produced the product as a white, fluffy lyophilized solid, yield 103mg (0.108mmol. 62.0%). MS (ES) m/e: 939 (M-H)\ Example 77 Boc-Tφ-DLvsfdPac^[2fHyTazfAsp Phe-NH,

Using the procedure of Example 4, the product of Example 34 (225mg, 0.326mmol) in DMF (25ml) was reacted in the presence of DIEA (105mg, O.δlmmol) with diphenyl- carbamyl chloride (75.5mg, 0.326mmol) for 1 hour. Purification by the method of Example 47 (solvent gradient 50-70% MeOH in H₂0), and collection of the solid pro¬ duced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 173mg (0.195mmol, 60.0%). MS (ES) m/e: 885 (M-H)^".

Example 78 Boc-Trp-LvsfPeac rf2fHYrazfAsp ]Phe-NH,

Using the procedure of Example 4, the product of Example 26 (80mg, O.llόmmol) in DMF (10ml) was reacted in the presence of DIEA (30mg, 0.23mmol) with phenylethyl isocyanate (15mg, 0.104mmol) for 2 hours. Purification by the method of Example 4 (solvent gradient 50-65% MeOH in H₂0), and collection of the solid produced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 48mg (0.056mmol, 49.6%). MS (FAB) m/e: 838 (M+H)⁺.

Example 79 Boc-Tφ-Lvsf2-BnPac^[2fH^N)TazrAsp)lPhe-NH.,

Using the procedure of Example 4, the product of Example 26 (95 mg, 0.138mmol) in DMF (10ml) was reacted in the presence of DIEA (35mg, 0.275mol) with 2-benzyl- phenyl isocyanate (29mg, 0.138mmol) for 2 hours. Purification by the method of Example 4 (solvent gradient 50-65% MeOH in H₂0), and collection of the solid pro- duced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 73.3mg (0.081mmol, 58.8%). MS (ES) m/e: 900 (M+H)⁺. Example 80 Boc-Trp-LvsfCn rr2fHyrazfAsp Phe-NH,

Using the procedure of Example 4. the product of Example 26, ( I50mg, 0.220mmol) in s DMF (15ml) was reacted in the presence of DIEA (85mg, 0.724mmol) with cinnamoyl chloride (36.6mg, 0.220mmol) for 20 minutes. Purification by reverse-phase HPLC by the method of Example 4 (solvent gradient 50-70% MeOH in H₂0) and collection of the solid produced during concentration of the eluant followed by vacuum drying over¬ night at 40°C provided the product as a white powder, yield 71mg (0.087mmol, 40.0%). o MS (ES) m/e: 821 (M+H)⁺.

Example 81 Boc-DTrp-Lvsf4Hcnιlr[2fHVrazfAsp Phe-NH,

s A synthesis analogous to that of Example 30 and its precursors was carried out with DTφ replacing Tφ. In the final step the title compound was synthesized from reaction of the D-Trp analog of Example 26, Boc-DTrp-Lysψ[2(H)Taz(Asp)]Phe-NH₂, (220mg, 0.320mmol) with 4-hydroxycinnamic acid N-hydroxysuccinimide ester (4Hci-Osu, 125mg, 0.480mmol) in the presence of NMM (570mg, 0.56mmol) overnight. Purification by the o method of Example 47 (solvent gradient 50-65% MeOH in H₂0), and collection of the solid produced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 61.6mg (0.0736mmol, 23.0%). MS (ES) m/e: 836 (M-H)^".

5 Example 82

Boc-Trp-LvsfPac ιur2fHYrazfDAsp Phe-NH.-

A synthesis analogous to that of Example 28 and its precursors was carried out with DAsp replacing Asp. In the final step the title compound was synthesized from reaction 0 of the DAsp analog of Example 26, Boc-Trp-Lysψ[2(H)Taz(DAsp)]Phe-NH₂, (350mg) in DMF (40ml) was reacted in the presence of DIEA (131mg, l.Olmmol) with phenyl isocyanate (54.3mg, 0.456mmol) for 1.5 hour. Purification by the method of Example 47 (solvent gradient 55-70% MeOH in H₂0), and collection of the solid produced during initial concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 228mg (0.282mmol, 55.6%). MS (FAB) m/e: 810 (M+H)⁺.

s Example 83

Boc-Tφ-LvsrTac')«lr[2rHVrazfGluηPhe-NH,

A synthesis analogous to that of Example 27 and its precursors was carried out with Glu replacing Asp. In the final step the title compound was synthesized from reaction of the o Glu analog of Example 26, Boc-Tφ-Lysψ[2(H)Taz(Glu)]Phe-NH,, (120mg, 0.170mmol) in DMF (15ml) was reacted in the presence of DIEA (74.2mg, 0.574mmol) with 2- methylphenyl isocyanate (19.2mg, 0.144mmol) for 1 hour. Purification by the method of Example 47 (solvent gradient 50-70% MeOH in H₂0), and collection of the solid pro- duced during initial concentration of the eluant followed by drying overnight at 40°C s under vacuum provided the product as a white powder, yield 95.2mg (0.114mmol, 66.8%). MS (ES) m/e: 838 (M+H)⁺.

Example 84 Boc-Trp-Lvsr4Hcnιir[2fHVrazfAsp DPhe-NH,

A synthesis analogous to that of Example 30 and its precursors was carried out with DPhe replacing Phe. In the final step the title compound was synthesized from reaction of the DPhe analog of Example 26, Boc-Trp-Lysψ[2(H)Taz(Asp)]DPhe-NH₂, (150mg, 0.217mmol) with 4-hydroxycinnamic acid N-hydroxysuccinimide ester (4Hci-Osu, 47mg, 0.217mmol) in the presence of DIEA (56mg, 0.434mmol) overnight. Purification by the method of Example 47 (solvent gradient 50-60% MeOH in H₂0), and collection of the solid produced during concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder,yield 59.0mg (0.0705m mol, 32.5%). MS (ES) m/e: 836 (M-H)^".

Example 85 Boc-Trp-LvsfTac m[2fHVrazfAsp ]HPhe-NH, A synthesis analogous to that of Example 27 and its precursors was carried out with HPhe replacing Phe. In the final step the title compound was synthesized from reaction of the HPhe analog of Example 26, Boc-Trp-Lysψ[2(H)Taz(Asp)]HPhe-NH₂, (150mg, 0.213mmol) in DMF (15ml) was reacted in the presence of DIEA (86.2mg, 0.724mmol) s with 2-methylphenyl isocyanate (28.4mg, 0.213mmol) for 1 hour. Purification by the method of Example 47 (solvent gradient 50-70% MeOH in H₂0), and collection of the solid produced during initial concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 75mg (0.090mmol, 42.0%). MS (ES) m/e: 824 (M+H)⁺. 0

Example 86 Boc-Trp-LvsfTac)ilr[2fH^N)TazfAsp ]Cha-NH,

A synthesis analogous to that of Example 27 and its precursors was carried out with Cha s (Cyclohexylalanine) replacing Phe. In the final step the title compound was synthesized from reaction of the Cha analogue of Example 26, Boc-Trp-Lysψ[2(H)Taz(Asp)]Cha- NH--₅ (200mg, 0.287mmol) in DMF (20ml) was reacted in the presence of DIEA (126mg, 0.976mmol) with 2-methylphenyl isocyanate (38.2mg, 0.287mmol) for 1 hour. Purifica¬ tion by the method of Example 47 (solvent gradient 50-75% MeOH in H₂0), and collec- tion of the solid produced during initial concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 102mg (0.123mmol, 42.8%). MS (ES) m/e: 830 (M+H)⁺.

Example 87 Boc-Trp-OmfTac1ιH2fHyrazfAsp Phe-NH-,

A synthesis analogous to that of Example 27 and its precursors was carried out with Orn replacing Lys. In the final step the title compound was synthesized from reaction of the Orn analog of Example 26. Boc-Tφ-Ornψ[2(H)Taz(Asp)]Phe-NH₂, (200mg, 0.296mmol) in DMF (20ml) was reacted in the presence of DIEA (115mg, 0.88mmol) with 2-methyl- phenyl isocyanate (39.4mg, 0.296mmol) for 1 hour. Purification by the method of Example 47 (solvent gradient 50-70% MeOH in H₂0), and collection of the solid pro¬ duced during initial concentration of the eluant followed by drying overnight at 40°C under vacuum provided the product as a white powder, yield 130mg (O.lόOmmol, 54.2%). MS (ES) m/e: 810 (M+H)⁺.

Example 88 s Boc-Tφ-DOmfTac^N)τJj[2rH'.TazfAspΗPhe-NH,

A synthesis analogous to the preparation of Example 27 and its precursors was carried out with DOrn replacing Lys. In the final step the title compound was synthesized from reaction of the DOrn analogue of Example 26, Boc-Tφ-DOrnψ[2(H)Taz(Asp)]Phe-NH₂, o (200mg, 0.296mmol) in DMF (20ml) was reacted in the presence of DIEA (115mg, 0.88mmol) with 2-methylphenyl isocyanate (39.4mg, 0.296mmol) for 1 hour. Purification by the method of Example 47 (solvent gradient 50-70% MeOH in H₂0), and collection of the solid produced during initial concentration of the eluant followed by drying over- night at 40°C under vacuum provided the product as a white powder, yield 145mg (0.179mmol. 60.3%). MS (ES) m/e: 810 (M+H)⁺.

Example 89

In the CCK-A binding assay described above, the compound of Example 46 was found to have a binding affinity (K versus BH-[^,25I]-CCK-8 of 8.7nM. The compound dis- played CCK-A agonist activity with 100% efficacy (relative to CCK-8) in the phosphat- idyl inositol hydrolysis assay at a concentration of lμM, and yielded an EC₅₀ of 130nM in the guinea pig gallbladder contraction assay. The compound inhibited feeding activity in rats with an RD_S0 of 1.2μg/kg in the 0.5 hour test and an RD₅₀ of l.lμg/kg in the 3 hour test.

Claims

Claims:

1. A compound of formula I;

wherein

R¹ represents H, NH--, C,^ alkyl optionally substituted by phenyl or naphthyl, R⁶CONH,

R⁷OCONH or R⁸NHCONH;

R² represents H or C,^ alkyl optionally substituted by phenyl; R³ represents H, phenyl or C,^ alkyl optionally substituted by phenyl, naphthyl or C₃^ cycloalkyl; the phenyl and naphthyl groups being optionally substituted by C,^ alkyl, C_1-6 alkoxy, halogen or hydroxy;

R⁴ represents H or CONR⁹R¹⁰;

R^s represents NH₂, NHCOR¹¹, NHCONR¹²R^12a, NHCOOR¹³ or NHS0₂R¹⁴; R⁶, R⁷ and R⁸ independently represent H, phenyl or C,^ alkyl optionally substituted by phenyl, naphthyl, 1- or 2-adamantyl or 3-quinuclidinyl; the phenyl and naphthyl groups being optionally substituted by C,^ alkyl, C-^ alkoxy, hydroxy, NO-_* NH-,, halogen, trifluo¬ romethyl, C0₂H, CH₂C0₂H, OS0₃H or NHS0₃H;

R⁹ and R¹⁰ independently represent H or C,^ alkyl; R¹¹ represents C_M alkyl, C₂^ alkenyl, phenyl or naphthyl, which groups are optionally substituted by phenyl or naphthyl; the phenyl and naphthyl groups being optionally substituted by C,^ alkyl, C alkoxy, hydroxy, NO,, NH,, halogen, trifluoromethyl, CO_:H,

CH₂C0₂H, OS0₃H or NHS0₃H;

R¹² represents H, phenyl, naphthyl or C,^ alkyl optionally substituted by phenyl or naphthyl; the phenyl and naphthyl groups being optionally substituted by C,^ alkyl, C,^ alkoxy, hydroxy, N0₂, NH₂, halogen, trifluoromethyl, benzyl, C0₂H, CH₂C0₂H, OS0₃H or NHS0₃H; R^12a represents H or phenyl;

R¹³ represents phenyl or C-^ alkyl optionally substituted by phenyl or naphthyl; the phenyl and naphthyl groups being optionally substituted by C,.₆ alkyl, C,.₆ alkoxy, hydroxy, N0₂, NH₂, halogen, trifluoromethyl, C0₂H, CH₂C0₂H, OS0₃H or NHS0₃H; R¹⁴ represents phenyl, naphthyl or C,^ alkyl optionally substituted by phenyl or naphthyl; the phenyl and naphthyl groups being optionally substituted by C^ alkyl, C,^ alkoxy, hydroxy, N0₂, NH₂, halogen, trifluoromethyl, C0₂H, CH₂C0₂H, OS0₃H or NHS0₃H; R^1S represents H or C,^ alkyl; m and n independently represent an integer from 1 to 4 inclusive; and p represents an integer from 3 to 7 inclusive; or a pharmaceutically acceptable salt thereof.

2. A compound as claimed in claim 1, wherein R¹ represents R⁶CONH or R⁷OCONH.

3. A compound as claimed in claim 1 or claim 2, wherein R² represents H.

4. A compound as claimed in any one of the preceding claims, wherein R³ repre¬ sents Cj.g alkyl substituted by phenyl.

5. A compound as claimed in any one of the preceding claims, wherein R⁴ repre¬ sents H or CONH₂.

6. A compound as claimed in any one of the preceding claims, wherein R^s repre- sents NHCOR¹¹ or NHCONHR¹².

7. A pharmaceutical formulation including a compound of formula I, as defined in claim 1, or a pharmaceutically acceptable salt thereof, in admixture with a pharma¬ ceutically acceptable adjuvant, diluent or carrier.

8. A compound of formula I, as defined in claim 1, or a pharmaceutically accept- able salt thereof, for use as a pharmaceutical.

9. The use of a compound of formula I, as defined in claim 1, or a pharmaceuti¬ cally acceptable salt thereof, in the manufacture of a medicament for the treatment of obesity.

10. A method of treatment of obesity which comprises administering a therapeutr- cally effective amount of a compound of formula I, as defined in claim 1, or a pharma¬ ceutically acceptable salt thereof, to a patient suffering from such a condition.

11. A method of improving the bodily appearance of a mammal which comprises administering to that mammal a compound of formula I as defined in claim 1. or a pharmaceutically acceptable salt thereof, until a cosmetically beneficial loss of body weight has occurred.

12. A process for the production of a compound of formula I, as defined in claim

1, or a pharmaceutically acceptable salt thereof, which comprises: (a) preparing a compound of formula I in which R² is C,^ alkyl optionally substi¬ tuted by phenyl, R⁵ is NHCOOR¹³ and R¹³ is C_w alkyl optionally substituted by phenyl or naphthyl, by reacting a compound of formula II,

in which R² and R⁵ are as defined immediately above and R³, R⁴, n and p are as defined in claim 1, with a compound of formula III,

H

in which R¹, R^1S and m are as defined in claim 1; (b) preparing a compound of formula I in which R⁵ is NHCONHR¹² by reacting the corresponding compound of formula I in which R⁵ is NH₂ with an isocyanate of formula

R¹²NCO in which R¹² is as defined in claim 1;

(c) preparing a compound of the formula I in which R^s is NHCOR¹¹ by reacting the corresponding compound of formula I in which R⁵ is NH₂ with an acid of formula RⁿCOOH in which R^u is as defined in claim 1, or an activated carboxylic acid derivative thereof; (d) preparing a compound of formula I in which R^s is NHS0₂R¹⁴ by reacting the corresponding compound of formula I in which R^s is NH₂ with a sulphonyl halide of formula R¹⁴S0₂X^d in which R¹⁴ is as defined in claim 1 and X° represents halogen;

(e) preparirg a compound of formula I in which R⁵ is NHCONR¹²(C₆H_s) by react- s ing the corresponding compound of formula I in which R⁵ is NH₂ with a compound of formula (C₆H₅)R¹²NCOX^e in which R¹² is as defined in claim 1 and X^e represents halogen; or

(f) removing a protecting group from a compound of formula I in which one or more of the amino, hydroxy or carboxy groups is protected; o and where desired or necessary converting the resulting compound of formula I into a pharmaceutically acceptable salt thereof or vice versa.

13. A compound of formula II,

wherein R² represents C,^ alkyl optionally substituted by phenyl, R⁵ is NHCOOR¹³ and R¹³ is C,^ alkyl optionally substituted by phenyl or naphthyl and R³, R⁴, n and p are as defined in claim 1.

14. A compound including a group of formula A,

wherein R,, R₁₊₁ and R₁₊₂ independently represent amino acid side chains, or a tauto- meric form thereof.

15. A process for the production of a compound including a group of formula A, as defined in claim 14, which comprises reaction of a compound including a group of formula Al,

wherein R- and R_i+1 independently represent amino acid side chains, or protected derivatives thereof, and L is a leaving group, with a compound including a group of formula All,

H

wherein R₁₊₂ represents an amino acid side chain, or a protected derivative thereof.