Patent GB-1532211-A (GB)
Title: Lh-rh peptide analogues
IPC: C07K7/23
Filed: 1974-10-25
Abstract: 1532211 Peptides having LH-RH activity WELLCOME FOUNDATION Ltd 24 Oct 1975 [25 Oct 1974] 46167/74 Heading C3H [Also in Division C2] A peptide of the formula an acid addition salt thereof or a complex thereof with a pharmaceutically-acceptable metal ion wherein X<SP>1</SP> is H-Pyroglu, V<SP>1</SP>-Pro-(wherein V<SP>1</SP> is acyl, alkyloxycarbonyl, aralkyloxycarbonyl), V<SP>2</SP>-CO (wherein V<SP>2</SP> is cycloalkyl); X<SP>2</SP> is His or a direct bond; X<SP>3</SP> is Phe (optionally substituted in the benzene ring, Trp; X<SP>4</SP> is Gly, Ser, Ala, D-Ala, D-Leu, D-Val; X<SP>5</SP> is Phe (optionally substituted in the benzene ring); X<SP>6</SP> is Gly, Ala, D-Ala, D-Leu, D-Val; X<SP>7</SP> is Phe (optionally substituted in the benzene ring), Leu; X<SP>8</SP> is a direct bond when X<SP>2</SP> is His, or X<SP>8</SP> is Arg or Homoarg when X<SP>2</SP> is a direct bond; W is Gly-NH 2 , amino, N-alkylamino, N,N- dialkylamino (wherein alkyl has 1-4 carbon atoms, optionally substituted by an hydroxyl group), pyrrolidino, morpholino, 1-methyl-5- aminoethyltetrazoyl; provided that, when X<SP>1</SP>, X<SP>3</SP>, X<SP>4</SP>, X<SP>5</SP>, X<SP>7</SP> and X<SP>8</SP> are, respectively, HPyroglu, Trp, Ser, Leu, Arg, W is other Gly- NH 2  or NHEt when X<SP>6</SP> is Gly, and is other than Gly-NH 2  when X<SP>6</SP> is D-Ala, may be prepared by a process which comprises the condensation of a reagent wherein Y<SP>1</SP> is selected from (i) a group X<SP>1</SP> as defined, (ii) a group cyclizable to L-pyroglutamyl, (iii) the L-prolyl radical and (iv) a partial sequence having one of the groups (i), (ii), (iii) as defined at its N-terminus and from thereon corresponding to the product; with a reagent wherein Y<SP>2</SP> corresponds to the balance of the product, the reagents Y<SP>1</SP>-OH and H-Y<SP>2</SP> being optionally protected and/or activated where and as appropriate and wherein, in the groups Y<SP>1</SP> and Y<SP>2</SP> thereof, as appropriate any L-arginyl or L-homoarginyl radical present in the product is optionally replaced by an L-ornithyl or L- lysyl radical respectively, followed, if necessary and as appropriate, by deprotection of the product, cyclization of the N-terminal group thereof to L-pyroglutamyl or protection of the N-terminal group with V<SP>1</SP> as defined, guanidation of any L-ornithyl or L-lysyl radical therein to L-arginyl or L-homoarginyl respectively, conversion of the product into the peptide base or an acid addition salt thereof, and complexing of the peptide with a pharmaceutically-acceptable metal ion. V<SP>1</SP> is preferably C 2-4  acyl, (C 1-4  alkyl) oxycarbonyl, benzyloxycarbonyl and V<SP>2</SP> preferably contains 3 to 7 carbon atoms. Preferred substituents in the benzene ring of L-phenylalanyl are methoxy, chlorine, methyl, hydroxyl, nitro and amino. Acetic acid is the preferred acid and zinc (II) the preferred metal ion. Y<SP>1</SP>-OH may correspond to X<SP>1</SP>-X<SP>2</SP>-X<SP>3</SP>- X<SP>4</SP>-X<SP>5</SP>-X<SP>6</SP> or X<SP>1</SP>-X<SP>2</SP>, and the condensation may be effected in dimethyl-formamide as solvent in the presence of dicyclohexylcarbodiimide and 1-hydroxybenzotriazole. Examples describe the preparation of H - Pyroglu - Phe -Ala - Tyr - Gly - Leu - Arg- Pro - NHEt; H - Pyroglu - His - Trp - Ser - Tyr - Gly - Leu - Pro - NHEt; H - Pyroglu - His - Trp - Ser - Tyr - Gly - Leu- Pro - Gly - NH 2 ; H - Pyroglu - Phe - Ala - Tyr - Gly - Leu - Arg- Pro - AMT; Boc - Pro - Phe - Ala - Tyr - Gly - Leu - Arg - Pro - NHEt; Cyclopentylcarbonyl - Phe - Ala - Tyr - Gly - Leu - Arg - Pro - NHEt. Peptide intermediates isolated are: OCTAPEPTIDES: Boc-Pro-Phe-Ala-Tyr- (Bzl)-Gly-Leu-Arg(NO 2 )-Pro-NHEt; H-Pyroglu- Phe-Ala-Tyr-Gly-Leu-Arg(NO 2 )-Pro-NHEt. HEPTAPEPTIDES: Z-Trp-Ser(Bzl)-Tyr(Bzl)- Gly-Leu-Pro-Gly-NH 2 ; H-Trp-Ser-Tyr-Gly- Leu-Pro-Gly-NH 2 . HEXAPEPTIDES: Z-Trp-Ser(Bzl)-Tyr(Bzl) Gly-Leu-Pro-NHEt; H-Trp-Ser-Tyr-Gly-Leu- Pro-NH 2 ; H-Pyroglu-Phe-Ala-Tyr-Gly-Leu- OBut and OH. PENTAPEPTIDES: Z-Trp-Ser(Bzl)-Tyr- (Bzl)-Gly-Leu-OBut and OH; Z and H-Phe-Ala- Tyr-Gly-Leu-OBut. TETRAPEPTIDES: Z-Trp-Ser(Bzl)-Tyr- (Bzl)-Gly-OCH 3  and OH; Z and H-Ala-Try- Gly-Leu-OBut. TRIPEPTIDES: Z and H-Tyr-Gly-Leu- OBu<SP>t</SP>; Boc-Leu-Arg(NO 2 )-Pro-NHEt. Dipeptide intermediates isolated are: Z and H-Gly-Leu-OBu<SP>t</SP>; Boc and H-Arg(NO 2 )- Pro-NHEt and AMT (AMT is 1-methyl-5- aminomethyltetrazole). Pharmaceutical compositions for the regulation of ovulation (in a non-human female mammal) or for the regulation of maturation of spermatoza (in a non-human male mammal) comprise peptides (I), a pharmaceutically-acceptable acid addition salt thereof or a complex thereof with a pharmaceutically-acceptable metal ion in admixture with a pharmaceutically-acceptable carrier. The carrier may be a finely-divided solid or a liquid and the compositions are preferably in unit dosage form with administration preferably being via nasal, parenteral, oral or vaginal route. Pharmaceutical compositions exemplified are: H - Pyroglu - Phe - Ala - Tyr - Gly - Leu - Arg - Pro - NHEt acetate plus (i) starch, lactose, polyvinylpyrrolidone, magnesium stearate; (ii) theobroma oil; (iii) lactose, starch, polyethylenglycol 6000, magnesium stearate; (iv) dilute acetic acid, 4-chloro-3-methylphenol, water.