PROCESS FOR OBTAINING NONAPEPTIDE AND DECAPEPTIDE DERIVATIVES OF HORMONE FOR RELEASING OF LUTEINIZING HORMONE

Nonapeptide and decapeptide analogs of LH-RH of the formula (pyro)Glu-His-V-Ser-W-X-Y-Arg-Pro-Z (I) and the pharmaceutically acceptable salt thereof wherein: V is tryptophyl, phenylalanyl or 3-(1-naphthyl)-L-alanyl; W is tyrosyl, phenylalanyl or 3-(1-pentafluorophenyl)-L-alanyl; X is a D-amino acid residue wherein R is (a) a carbocyclic aryl-containing radical selected from the group consisting of naphthyl, anthryl, fluorenyl, phenanthryl, biphenylyl, benzhydryl and phenyl substituted with three or more straight chain lower alkyl groups; or (b) a saturated carbocyclic radical selected from the group consisting of cyclohexyl substituted with three or more straight chain lower alkyl groups, perhydronaphthyl, perhydrobiphenylyl, perhydro-2,2-diphenylmethyl and adamantyl; Y is leucyl, isoleucyl, nor-leucyl or N-methyl-leucyl; Z is glycinamide or -NH-R , wherein R is lower alkyl, cycloalkyl, fluoro lower alkyl or -NH-@-NH-R wherein R is hydrogen or lower alkyl, are disclosed. These compounds exhibit potent LH-RH agonist properties.