CA2054667A1

CA2054667A1 - Cyclopeptides

Info

Publication number: CA2054667A1
Application number: CA002054667A
Authority: CA
Inventors: Guenter Hoelzemann; Alfred Jonczyk; Juergen Harting; Hartmut Greiner
Original assignee: Individual
Current assignee: Merck Patent GmbH
Priority date: 1990-11-02
Filing date: 1991-10-31
Publication date: 1992-05-03
Also published as: IE913831A1; HUT61582A; ZA918717B; EP0484719A2; PT99384A; JPH04300895A; DE4034829A1; KR920009846A; HU913450D0; EP0484719A3; AU8676291A; CS331491A3

Abstract

A B S T R A C T

The invention relates to novel cyclopeptides of the formula I
I
in which A,B,C,X and Y have the meanings indicated in Claim 1. These substances have, inter alia, bronchial muscle relaxant and anti-inflammatory activity.

Description

Merck Patent Gesellschaft mit beschr~nkter Haftung 6100 D a r m s t a d t Cyclopeptides The invention relates to novel cyclopeptides of the formula I

- A-B-C-X-in which A i8 Asn, Asp~OR), Gln, Glu(OR), Hypro, Ly~, Orn, Ser or Thr, 10 B and C are each N~-MePhe, N~-MeTrp, Phe, Tcc, Tic, Trp or Tyr, X is Gly, (S,S)-Gly-tANC-2]-Leu, or, if A is not equal to Gln, also Gly-Leu, Y i3 Leu, Met, Met(O), Met(O2) or Nle, X-Y together are also Gly-Leu(red)- Leu and R i8 H, alkyl having 1-4 C atoms or benzyl, and their salt~.
Similar compounds are known from Pharmazie 40 (8), 532-5, (1985).
The ob~ect of the invention wa~ to find novel compounds having useful properties, in particular those which can be used for the preparation of medicaments.
It has been found that the compounds of the formula I and their salt~ have very useful properties. In particular, they have a tachykinin antagonist (e.g. anal-gesic) effect. Thi~ analgesic effect can be detected, e.g. by the methods which are given in US-A-4,472,305, e.g. in the writhing test on rats or mice (for method compare C. Vander Wende and S. Margolin, Fed. Proc. 15, 494 ff. (1956); E. Siegmund et al., Proc. Soc. exp. Biol.
(NY) 95, 729-731 (1957); L.L. Hendershot and J. Forsaith, J. Pharmacol, exp. Ther. 125, 237-240 (1959)). In addition, there are anti-inflammatory and/or spasmolytic ~ ~ ~ 4 ~

effects. Furthermore, the compounds of the formula I show a relaxant effect on the bronchial musculature.
The compounds can be employed as pharmaceutical active compounds in human and veterinary medicine, in particular for the prophylaxis and the treatment of asthmatic disorders, spastic disorders, states of pain, inflammations, disorders of the central nervous system and/or the circulation.
The abbreviations of amino acid radicals shown above and below ~tand for the radical~ of the following amino acid~:
Asn asparagine Asp(OR) aspartic acid (ester) Gln glutamine 15 Glu(OR) glutamic acid ~ester) Gly glycine Hypro hydroxyprolina Leu leucine Lys lysine Met methionine ~et(O) methionine S-oxide Met( 2 ) methionine-S,S-dioxide Nle norleucine N~-Me-Phe N-methyl-phenylalanine 25 N~-MeTrp N~-methyl-tryptophan Orn ornithine Phe phenylalanine Ser serine Tcc 1,2,3,4-tetrahydro-~-carboline-3-carboxylic acid Tic 1,2,3,4-tetrahydroisoquinoline-1-carboxylic acid Trp tryptophan Tyr tyrosine.
35 In addition, the following have the meanings below:
BOC tert.-butoxycarbonyl CBZ benzyloxycarbonyl DCCI dicyclohexylcarbodiimide DMF dimethylformamide 2~a~7 EDCI N-ethyl-N'-(3-dimethylaminopropyl)-carbodi-imidehydrochloride FMOC 9-fluorenylmethoxycarbonyl r(cH2)21 S Gly-[ANC-2]-leu- the radical -HN-CH-CO---N-CH(i-C4H9)-CO-HOBt 1-hydroxybenzotriazole Leu(red) the radical -HN-CH(i-C4Hg)-CH2 Me methyl OMe methyl ester OEt ethyl ester POA phenoxyacetyl TFA trifluoroacetic acid If the amino acids mentioned above can occur in several enantiomeric forms, then all these forms and al~o their mixtures (e.g. the DL-forms) are included above and below, e.g. as constituents of the compounds oi the formula I. The L-forms are preferred. If individual compound~ are mentioned below, then the abbreviations of these amino acids in each case relate to the L-form, if not expre~sly stated otherwise.
The invention further relate~ to a process for the preparation of a cyclopeptide of the formula I, characterized in that i~ i~ liberated from one of it~
functional derivatives by treating with a ~olvolyzing or hydrogenolyzing agent, or in that a peptide of the formula II
H-Z-OH

in which Z is A-B-C-X-Y, B-C-X-Y-A, C-X-Y-A-B, X-Y-A-B-C, Leu Y-A-B-C-Gly, Y-A-B-C-X or Leu~red)-Leu-A-B-C-Gly, or a reactive derivative of such a peptide is treated with a cyclizing agent, and in that, if appropriate in a 207~b~7 compound of the formula I, a thioether group is oxidized to a sulfoxide group or to a sulfone group and/or a compound of the formula I is converted into one of its salts by treating with an acid.
The radicals ~ as well as A, B, C, X, Y and Z
above and below have the meanings given in the formulae I or II, if not expressly stated otherwise.
In the above formulae, A preferably corresponds to one of the amino acids Gln, Gln(OR), Hypro and Ser, but al80 Asn, A~p(OR), Lys, Orn and Thr, R is H, alkyl (1-4 C atoms) or benzyl, alkyl prefsrably being methyl, ethyl, isopropyl or tert butyl.
B preferably corresponds to one of the amino acids Trp and Phe, but ~ust like C which preferably corre~ponds to Phe, i8 also N~-MePhe, N~-MeTrp, Tcc, Tic or Tyr.
X is equally Gly, Gly-leu or (S,S)-Gly-[ANC-2]-leu, Gly-leu being possible only if A is not equal to Gln.
Furthermore, Y preferably is Leu or Met, but also Met(O), Met( 2 ) or Nle, the D configuration being preferred in these cases.
However, X and Y together can also be the component Gly-leu(red)-leu.
~ccordingly, the invention in particular relate~
to tho~e compounds of the formula I in which at least one of the said radicals has one of the preferred meanings qiven above.
A preferred group of compounds can be expressed by the part formula Ia, which otherwise corresponds to the formula I, but in which A is Gln, D-Gln, Glu, Glu(OtBu), Hypro or Ser, B is Trp, C is Phe, X is Gly, Gly-leu (where A is not equal to Gln) or (StS)-Gly-[ANC-2]-leu, Y is Leu, Met or D-Met, X-Y together are also Gly-leu(red)-leu.
The compounds of the formula I and also the tarting materials for their preparation are otherwise prepared by known methods, as are described in the literature ~e~g. in the standard works such as Houben-Weyl, Methoden der organischen Chemie, (Methods of s Organic Chemistry) Georg-Thieme-Yerlag, Stuttgart), in particular under reaction conditions which are known and suitable for the said reactions. In this context, use can also be made of known variants which are not mentioned in more detail here.
~he starting substances can also be formed in situ, if desired, ~uch that they are not isolated from the reaction mixture, but immediately reacted further to give the compounds of the formula I.
~he compounds of the formula I can be obtained by liberating them from their functional derivatives by solvolysis, in particular hydrolysis, or by hydrogenolysis.
Preferred starting materials for the solvolysis or hydrogenolyRis are those which contain appropriate protected amino and/or hydroxyl groups instead of one or more free amino and/or hydroxyl groups, preferably those which carry an amino protecting group instead of an H
atom which is bonded to an N atom, e.g. those which correspond to the formula I, but contain an NHR~ group (in which R' is an amino protecting group, e.g. BOC or CBZ) instead of an NH2 group.
In addition, starting materials are preferred which carry a hydroxyl protecting group instead of the H
ato~ of a hydroxyl group, e.g. those which correspond to the formula I, but contain an R''O-phenyl group (in which R'' is a hydroxyl protecting group) instead of a hydroxy-phenyl group.
Several - identical or different - protected amino and/or hydroxyl group~ can be present in the molecule of the starting material. If the protective groups present are different from one another, in many cases they can be removed selectively.
The expression ~amino protecting group~ i5 generally known and relates to groups which are suitable ~5~ 7 for protecting (for blocking) an amino group from chemi-cal reactions, but which are easily removable, after the desired chemical reaction has been carried out on other positions of the molecule. Typical groups of this type are, in particular, unsubstituted or substituted acyl, aryl, aralkoxymethyl or aralkyl groups. As the amino protecting groups are removed after the desired reaction (or reaction sequence), their nature and size i8 otherwise not critical; but those having 1-20, in particular 1-8, C atoms are preferred. The expression "acyl group" is to be taken in its widest sense in connection with the present process. It includes acyl groups derived from aliphatic, araliphatic, aromatic or heterocyclic carboxylic acids or sulfonic acids and in lS particular alkoxycarbonyl, aryloxycarbonyl and, above all, aralkoxycarbonyl groups. Examples of acyl groups of thi~ type are alkanoyl such as acetyl, propionyl or butyryl; aralkanoyl such as phenylacetyl aroyl such as benzoyl or toluyl; aryloxyalkanoyl such as POA; alkoxy-carbonyl such as methoxycarbonyl, ethoxycarbonyl, 2,2,2-trichloroethoxycarbonyl, BOC, 2-iodoethoxycarbonyl;
aralkyloxycarbonyl such as CBZ ("carbobenzoxy"), 4-methoxybenzyloxycarbonyl and FMOC. Preferred amino protecting groups are BOC, and in addition CBZ, FMOC, benzyl and acetyl.
~ he expression "hydroxy protecting group" is also generally known and relates to groups which are suitable for protecting a hydroxyl group from chemical reactions, but which are easily removable, after the desired chemi-cal reaction has been carried out on other positions ofthe molecule. Typical groups of this type are the above-mentioned unsubstituted or substituted aryl, aralkyl or acyl groups, and in addition al80 alkyl groups. The nature and size of the hydroxy protecting groups is not critical, as they are removed again after the desired chemical reaction or reaction sequence; preferred groups are those having 1-20, in particular 1-lO C atoms.
Ex~mples of hydroxyl protecting groups are, inter alia, benzyl, p-nitrobenzoyl, p-toluenesulfonyl and acetyl, 2 ~

benzyl and acetyl being particularly preferred.
The functional derivatives of the compounds of the fonnula I to be used as starting materials can be prepared by customary methods of amino acid and peptid~
synthesis, such as are described e.g. in the standard works and patent applications mentioned, and e.g. also by the Merrifield solid pha~e method (B.F. Gysin and R.B.
Merrifield, J. Am. Chem. Soc. 94, 3102 et seq. t1972)).
The liberation of the compounds of the formula I
from their functional derivatives is carried out depending on the protecting group used - e.g. with strong acids, preferably with TFA or perchloric acid, but also with other strong inorganic acids such as hydrochloric acid or sulfuric acid, or strong organic carboxylic acids such a~ trichloroacetic acid or sulfonic acids such as benzene- or p-toluenesulfonic acid. The presence of an additional inert solvent is possible, but not always necessary. Suitable inert solvents are preferably organic, for example carboxylic acids such as acetic acid, ethers such as tetrahydrofuran or dioxane, amides such as DMF, halogenated hydrocarbon~ such as dichloro-methane, and in addition also alcohols such as methanol, ethanol or isopropanol and also water.
In addition, mixtures of the abovementioned 801vents are suitable. TFA i8 preferably used in an excess without addition of a further solvent, perchloric acid in the form of a mixture of acetic acid and 70 %
perchlori~ acid in the ratio 9:1. The reaction temper-atures for the cleavage are preferably between about O
and about 50, preferably between 15 and 30 (room temperature).
The BOC group can be removed e.g. preferably using 40 ~ TFA in dichloromethane or with about 3 to 5 N
HCl in dioxane at 15-30, the FMOC group using an about ~5 5- to 20 ~ solution of dimethylamine, diethylamine or piperidine in DMF at 15-30.
Protecting groups which can be removed by hydro-genolysis (e.g. CBZ or benzyl) can be removed, e.g. by treating with hydrogen in the presence of a catalyst 2 ~

(e.g. a noble metal catalyst such as palladium, preferab-ly on a carrier such as carbon). Suitable solvents in this case are those mentioned above, in particular e.g.
alcohols such as methanol or ethanol or amides such as S DMF. The hydrogenolysis is carried out, as a rule, at temperature~ between about 0 and 100 and pressure~
between about 1 and 200 bar, preferably at 20-30 and 1-10 bar. Hydrogenolysis of the CBZ group is easily carried out e.g. on 5 to 10 % Pd-C in methanol or using ammonium formate tinstead of H2) on Pd-C in methanol/DMF at 20-30.
Compounds of the formula I can also be obtained by cyclization of compounds of the formula II under the conditions of a peptide synthesis. In this case, the reaction is preferably carried out by customary methods of peptide synthesi~, as are described e.g. in Houben-Weyl, loc cit. volume 15/II, pages 1 to 806 (1974).
The reaction is preferably carried out in the presence of a dehydrating agent, e.g. a carbodiimide ~uch as DCCI or EDCI, and in addition propanephosphonic anhydride (compare Angew. Chem. 92, 129 (1980)~, diphen-ylphosphoryl azide or 2-ethoxy-N-ethoxycarbonyl-1,2-di-hydroquinoline, in an inert solvent, e.g. a halogenated hydrocarbon such as dichloromethane, an ether such as tetrahydrofuran or dioxane, an amide such as DMF or dimethylacetamide, a nitrile such as acetonitrile, or in mixtures of these solvents, at temperatures between about -10 and 40, preferably between 0 and 30. In order to promote intramolecular cyclization before intermolecular peptide bonding, it is preferable to work in dilute solutions (dilution principle).
Instead of II, suitable reactive derivatives of these sub3tances can also be employed in the reaction, e.g. those in which reactive groups are intermediately blocked by protecting groups. The amino acid deriv-atives II can be used e.g. in the form of their activated esters which are preferably formed in situ, e.g. by addition of HOBt or N-hydroxysuccinimide.
The star~ing materials of the formula II are, as a rule, novel. They can be prepared by known methods, ~5~7 g e.g. the abovementioned methods of peptide synthesis and of removal of protective groups.
As a rule, protected penta- or hexapeptide esters of the formula R'-Z-OR'', e.g. BOC-Z-OMe or BOC-Z-OEt are initially synthesized, which are first hydrolyzed to give acids of the formula R'-Z-OH, e.g. BOC-Z-OH; the protec-tive group R' is removed from these, by means of which the free peptides of the formula H-Z-OH (II) are obtained.
It is also possible to oxidize a thioether group to a sulfoxide group or sulfone group, in particular a group Y = Met to a group Y = Met(O) or Met( 2 ) ~ e.g. by passing air into a solution of the compound of the formula I tY = Met) in acetonitrile/water at temperatures between O and 30. The thioether can also be oxidized with H2~2. The sulfoxide is thu~ predominantly obtained at 20 in methanol using the calculated amount of oxidizing agent, and the sulfone is predominantly obtained at 50, on the other hand, using an excess of the oxidizing agent.
Conversely, a ulfoxide group (e.g. in I, Y
= ~et(o)) can be reduced to give a thioether group (e.g.
in I, Y = Met), e.g. using NH4I in aqueous TFA at temperatures between -10 and 25.
A base of the formula I can be converted into the appropriate acid addition salt using an acid. Suitable acids for this reaction are in particular those which yield physiologically acceptable salts. Inorganic acids can thu~ be used, e.g. sulfuric acid, nitric acid, hydrohalic acids such as hydrochloric acid or hydrobromic acid, phosphoric acids such a~ orthopho~phoric acid and sulfamic acid, and in addition organic acids, in par-ticular aliphatic, alicyclic, araliphatic, aromatic or heterocyclic mono~ or polybasic carboxylic, sulfonic or sulfuric acids, e.g. formic acid, acetic acid, propionic acid, pivalic acid, diethylacetic acid, malonic acid, succinic acid, pimelic acid, fumaric acid, maleic acid, lactic acid, tartaric acid, malic acid, benzoic acid, salicylic acid, 2- or 3-phenylpropionic acid, citric 2 ~ t) ~ 7 acid, ~luconic acid, ascorbic acid, nicotinic acid, isonicotinic acid, methane- or ethanesulfonic acid, ethanedisulfonic acid, 2-hydroxyethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthal-ene-mono- and -disulfonic acids, and laurylsulfuric acid.
Salts with physiologically unacceptable acids, e.g.
picrates, can be used for the isolation and/or purifica-tion of the compounds of the formula I.
The novel compounds of the formula I and their physiologically acceptable salts can be used for the production of pharmaceutical preparations by bringing them into a suitable dosage form together with at least one excipient or auxiliary and, if desired, together with one or more other active compound(s~. The preparations thus obtained can be employed as pharmaceuticals in human or veterinary medicine. Suitable excipient sub tances are organic or inorganic subs~ances which are suitable for enteral (e.g. oral or rectal), parenteral or local (e.g.
topical) administration or for administration in the form of an inhalant spray and which do not react with the novel compounds, for example water, lower alcohols, vegetable oils, benzyl alcohols, polyethylene glycols, glycerol triacetate and other fatty acid glycerides, gelatin, soya lecithin, carbohydrates such as lactose or starch, magn~sium stearate, talc, cellulose and vaseline.
Tablets, coated tablet~, capsules, syrups, liquids or drop~, in particular, are used for oral administration;
film tablets and capsules having ga~tric ~uice-resistant coatings or capsule shells are especially of interest.
Suppositories are used for rectal administration, and solutions, preferably oily or aqueous solutions, and in addition suspensions, emulsions or implants, are used for parenteral administration. Solutions, e.g., which can be used in the form of eye drops, and in addition, e.g.
suspensions, emulsions, creams, ointments or compresses are suitable for topical application. Sprays can be used which contain the active compound either dissolved or suspended in a propellant gas mixture (e.g. chlorofluoro-hydrocarbons) for administration as inhalant sprays. The active compound here i5 preferably used in micronized form, it being possible for one or more additional physiologically tolerable solvents to be present, e.g.
ethanol. Inhalant solutions can be administered with the aid of customary inhalers. The novel compounds can also be lyophylized and the lyophylizates obtained used e.g.
for the production of in~ection preparations. The prepar-ations indicated can be sterilized and/or can contain auxiliaries such as preservative~, stabilizers and/or wetting agents, emulsifiers, ~alts for influencing osmotic pressure, buffer substances, colorants and/or flavourings. If desired, they can also contain one or more other active compounds, e.g. one or more vitamins.
The substances according to the invention are as a rule administered in analogy to other known commercial-ly available peptide~, but in particular in analogy to the compounds described in US-A-4,472,305, preferably in dosages between about 0.05 and 500, in particular between 0.5 ~nd 100 mg per dosage unit. The daily dose i8 prefer-ably between about 0.01 and 2 mg/kg of body weight. Thespecific dose for each intended patient depends, however, on many different factors, for example the activity of the ~pecific compound employed, the age, ~ody weight, general state o health, sex, the cost, the tLme and route of administration, and the rate of excretion, pharmaceutical combination and severity of the particular disorder to which the therapy applies. Parenteral admini-~tration is preferred.
All temperatures above and below are stated in C. In the following examples, "customary working up"
means: water is added, if necessary, the mixture is neutralized and extracted with ether or dichloromethane, the organic phase is separated off, dried over sodium sulfate, filtered and evaporated and the residue is purified by chromatography on silica gel and/or crystal-lization. RT = retention time (minutes) for HPLC on an RP 18 250-4 column, if not stated otherwise; eluent:
a = water, b = 0.3 % TFA in water, c = acetonitrile.
Rf = R~ value by thin-layer chromatography on silica gel;

2 ~ 7 eluent: chloroform/methanol/acetic acid 85:10:5.
Example 1 2.0 g of BOC-Leu-D-Met-H~pro-Trp-Phe-Gly-OMe are dissolved in 60 ml of methanol, l.S ml of 2 N sodium S hydroxide solution are added and the mixture is stirred for 3 hours at 20. After evaporation the residue is taken up in water, acidified to pH 3 with dilute HCl and extracted with ethyl acetate. The extract is dried over Na2SO4, evaporated again and the BOC-Leu-D-Met-Hypro-Trp-Phe-Gly-OH obtained i9 stirred at 20 for 2 hours with 20 ml of 2 N HCl in dioxane. The mixture i5 evaporated, the H-Leu-D-Met-Hypro-Trp-Phe-Gly-OH obtained is dissolved in a mixture of 1800 ml of dichloromethane and 200 ml of DMF and cooled to 0, 0.5 g of DCCI, 0.3 g of ~OBt and 0.23 ml of N-methylmorpholine are added succe3~ively with stirring, and the mixture is ~tirred for a further 24 hours at 0 and 48 hours at 20. The solution is concentrated and treated with a mixed bed ion exchanger to free it from salts. This is then filtered off, the solution is e~aporated and the residue i~
purified by chromatography. Cyclo(-Hypro-Trp-Phe-Gly-Leu-D-Met-) i~ obtained; m.p. 175.
The following are obtained analogously:
from BOC-A~n-Trp-Tic-Gly-Leu-D-Met-OEt:
Cyclo-[-AEn-Trp-Tic-Gly-Leu-D-Met-]
from BOC-Phe-Gly-Leu(red)-Leu-D-Gln-Trp-OMe:
Cyclo-[-D-Gln-Trp-Phe-Gly-Leu(red)-Leu-], m.p.189 from BOC-Gln-Trp-PhQ-(S,S)-Gly-[ANC-2]-Leu-Met-OEt:
-Cyclo-[-Gln-Trp-Phe-(S,S)-Gly-[ANC-2]-Leu-Met-], m.p. 186 from BOC-Gly-Leu(red)-Leu-Gln-Trp-Phe-OMe:
Cyclo-[-Gln-Trp-Phe-Gly-Leu(red)-Leu-], m.p. 195 from BOC-Trp-Phe-Gly-Met-Gln-OMe:
Cyclo-[-Gln-Trp-Phe-Gly-Met-], m.p. from 280 (dec.) from BOC-Phe-Gly-Leu-D-Leu-Glu-Trp-OMe:
Cyclo-[-Glu-Trp-Phe-Gly-Leu-D~Leu-]
from BOC-Glu-Trp-Phe-Gly-Leu-Leu-OEt:
Cyclo-[-Glu-Trp-Phe-Gly-Leu-Leu-], R~ 0.45 2 ~3 ~ ~ $ 7 from BOC-Phe-Gly-Leu-Leu-Glu(OtBu)-Trp-OMe:
Cyclo-[-Glu(OtBu)-Trp-Phe-Gly-Leu-Leu-], Rf 0.6 from BOC-Hypro-Phe-Phe-Gly-Leu-D-Met-OMe:
Cyclo-[-Hypro-Phe-Phe-Gly-Leu-D-Met-]
S from BOC-Hypro-Phe-Tyr-Gly-Leu-D-Met(O)-OMe:
Cyclo-[-Hypro-Phe-Tyr-Gly-Leu-D-Met(O)-]
from BOC-Hypro-Phe-Tyr-Gly-Leu-D-Met(Oz)-OMe:
Cyclo-[-Hypro-Phe-Tyr-Gly-Leu-D-Met( 2 ) - ]
from BOC-Hypro-Trp-Phe-Gly-Leu-Met-OMe:
Cyclo-[-Hypro-Trp-Phe-Gly-Leu-Met-], m.p. 175 from BOC-Phe-Phe-Gly-D-Leu-Lys-OMes Cyclo-[-Lys-Phe-Phe-Gly-D-Leu-]
from BOC-Trp-Phe-Gly-Leu-D-Leu-Lys-OMe:
Cyclo-[-Lys-Trp-Phe-Gly-Leu-D-Leu-.]
from BOC-Ser-Trp-Phe-(S,S)-Gly-[ANC-2]-Leu-D-Met-OMe:
Cyclo-[-Ser-Trp-Phe-(S,S)-Gly-[ANC-2]-Leu-D
-Met-]
from BOC-Ser-Trp-Phe-Gly-Leu-D-Met-OMe:
Cyclo-[-Ser-Trp-Phe-Gly-Leu-D-Met-]
20 from BOC-Ser-Trp-Phe-(S,S)-Gly-[ANC-2]-Leu-Met-OMe:
Cyclo-[-Ser-~rp-Phe-(S,S)-Gly-[ANC-2]-Leu-Met-].

Example 2 A solution of 1.5 g of BOC-Ser-Trp-Phe-Gly-Leu-Met-OMe in methanol (50 ml) is treated with 2 ml of hydrazine hydrate, stirred for 16 hours and evaporated.
The BOC-Ser-Trp-Phe-Gly-Leu-Met-NH-NHzobtained is stirred at 20 for 2 hours with 20 ml of 2 N HCl in dioxane.
Evaporation gives the H-Ser-Trp-Phe-Gly-Leu-Met-NH-NH2 dihydrochloride which is dissolved in 50 ml of DNF. It is cooled to -15 with stirring, and 0.83 ml of 35 %
hydrochloric acid and 1.5 ml of a 14 % aqueous NaNO2 solution are added successively. The mixture i~ stirred at -15 for 1 hour and poured into 2 1 of cooled DMF, 1.1 ml of N-methylmorpholine are added, and the mixture is stirred for a further 24 hour~ at -15 and then for 2 days at 20. The solution is concentrated, a mixed bed ion exchanger is added to remove salts, the mixture is filtered, the filtrate is evaporated, and the residue is 2 ~ ~ ~ 6 ~; 7 purified by chromatography to give cyclo(-Ser-Trp-Phe-Gly-Leu-Met-~; R~ 0.5 The following are obtained analogously:
from BOC-Gln-Trp-D-Phe-Gly-Leu-D-Met-OMe:
Cyclo-[-Gln-Trp-D-Phe-Gly-Leu-D-Net-]
from BOC-Gln-Trp-Phe-Gly-D-Met-OMe:
Cyclo-[-Gln-Trp-Phe-Gly-D-Met-], m.p. from 280 (dec.) from BOC-Ser-Phe-Phe-Gly-Leu-D-Met-OMe:
Cyclo-[-Ser-Phe-Phe-Gly-Leu-D-Met-]
from BOC-Ser-Trp-Phe-Gly-Leu-Nle-OMe:
Cyclo-[-Ser-Trp-Phe-Gly-Leu-Nle-].

Example 3 A solution of 100 mg of cyclo(-Gln-Trp-Phe-Gly-Met-~ and 1 equivalent of 30 % H202 solution in 50 ml of methanol is stirred at 20 for 2 hours. Evaporation and customary working up give cyclo[-Gln-Trp-Phe-Gly-Net(O)-].
Example 4 A solution of 100 mg of cyclot-Hypro-Trp-Phe-Gly-Leu-D-Met-J and 10 equivalents of 30 % H202 solution in 50 ml of methanol is warmed to 50 for 2 hours.
Evaporation and customary working up give cyclo~-Hypro-Trp-Phe-Gly-Leu-D-Met( 2 ) - ] -.
Exampl~ 5 Air i8 passed through a solution of 1 g of cyclo[-Asn-Trp-Tic-Gly-Leu-D-Met-) in 50 ml of acetonitrile and 50 ml of water until reaction i8 complete. Customary working up gives the corresponding 8ul foxide cyclo[-Asn-Trp-Tic-Gly-Leu-D-Met(O)-].

Example 6 20 ml of a 2 M NH4I solution is added at O to a solution of 1 g of cyclot-Ser-D-Trp-Phe-Gly-Leu-Met(O)-]
in 50 ml of TFA. After stirring at 0 for 1 hour, the resulting iodine is reduced by adding thioglycolic acid, and the mixture i5 worked up a~ i8 customary to give 2 ~ 5 ~

cyclot-Ser-D-Trp-Phe-Gly-Leu-Met-).
The following are obtained analogously from the corresponding oxidized cyclic peptides:
Cyclo-[-Ser-Phe-Tyr-Gly-Leu-D-Met-]
Cyclo-[-Ser-Trp-N~-MePhe-Gly-keu-D-Met-].

The example~ below relate to pharmaceutical preparations.

Example A: In~ection vials A solution of 100 g of cyclo[-Ser-Trp-Phe-Gly-Leu-Met-) and 5 g of disodium hydrogenphosphate in 31 of doubly distilled water is ad~u~ted to pH 6.5 with 2 N
hydrochloric acid, sterile filtered, filled into in~ec-tion vials and lyophilized under sterile conditions, and the vials are closed in a sterile manner. Each in~ection vial contain~ 5 mg of active compound.

Example B: Suppositories A mixture of 20 g of cyclo[-Glu-Trp-Phe-Gly-Leu-Leu-) is fused with 100 g of ~oya lecithin and 1400 g of cocoa butter, and the mixture is poured into mould~ and allowed to cool. Each suppository contains 20 mg of - active compound.

Example C: Solution A solution of 1 g of cyclo[-Glu-Trp-Phe-Gly-Leu-D-Leu-], 9.38 g of NaH2PO4.2H20, 28.48 g of Na2HPO4.12H20 and 0.1 g of benzalkonium chloride is prepared in 940 ml of doubly distilled water. The solution is ad~usted to pH 6.8, made up to 1 1 and sterilized by irrad$ation.
This solution can be used in the form of eye drops.

Example D: Ointment 500 mg of cyclot-Ser-Phe-Tyr-Gly-Leu-D-~et-) is mixed with 99.5 g of petroleum ~elly under aseptic condition~.

Claims

1. Cyclopeptides of the formula I

I

in which A is Asn, Asp(OR), Gln, Glu(OR), Hypro, Lys, Orn, Ser or Thr, B and C are each N.alpha.-MePhe, N.alpha.-MeTrp, Phe, Tcc, Tic, Trp or Tyr, X is Gly, (S,S)-Gly-{ANC-2]-Leu, or, if A is not equal to Gln, also Gly-Leu, Y is Leu, Met, Met(O), Met(O2) or Nle, X-Y together are also Gly-Leu(red)- Leu and R is H, alkyl having 1-4 C atoms or benzyl, and their salts.

2. a) Cyclo[-Gln-Trp-Phe-Gly-D-Met-);
b) Cyclo[-Hypro-Trp-Phe-Gly-Leu-Met-];
c) Cyclot-Hypro-Trp-Phe-Gly-Leu-D-Met-).

3. Process for the preparation of a cyclopeptide of the formula I according to Claim 1, characterized in that it is liberated from one of its functional derivatives by treating with a solvolyzing or hydrogenolyzing agent, or in that a peptide of the formula II
H-Z-OH II
in which Z is , Y-A-B-C-X or Leu(red)-Leu-A-B-C-Gly, or a reactive derivative of such a peptide with a cyclizing agent, and in that, if appropriate in a com-pound of the formula I, a thioether group is oxidized to a sulfoxide group or to a sulfone group and/or a sulf-oxide group is reduced to a thioether group and/or a compound of the formula I is converted into one of its salts by treating with an acid.

4. Method for the production of pharmaceutical preparations, characterized in that a compound of the formula I and/or one of its physiologically acceptable salts are brought into a suitable dosage form together with at least one solid, liquid or semisolid excipient or auxiliary.

5. Pharmaceutical preparation, characterized in that it contains at least one compound of the formula I and/or one of its physiologically acceptable salts.

6. Use of compounds of the formula I or their physiologically acceptable salts for the production of a medicament.

7. Use of compounds of the formula I or their physiologically acceptable salts in the control of cardiovascular disorders, spastic disorders, states of pain, inflammations, disorders of the central nervous system and/or the circulation and/or in the stimulation of lacrimal secretion.