Nonapeptide and decapeptide analogs of LHRH which have the formula
and the pharmaceutically acceptable salts thereof, wherein:
A is an amino acyl residue selected from the group consisting of L-pyroglutamyl, D-pyroglutamyl, N-acyl-D,L-tryptophanyl, N-acyl-glycyl, N-Ac-D,L-Δ 3,4 -prolyl, N-Ac-D,L-prolyl, N-Ac-L-alkylprolyl, N-Ac-D,L-phenylalanyl, N-Ac-D,L-p-chlorophenylalanyl, N-Ac-D,L-seryl, N-Ac-D,L-threonyl, N-Ac-D,L-alanyl, 3-(1-naphthyl)-D,L-alanyl, 3-(2-naphthyl)-D,L-alanyl, 3-(2,4,6-trimethylphenyl)-D,L-alanyl, 3-(4-trifluoromethylphenyl)-D,L-alanyl, 3-(9-anthryl)-D,L-alanyl, 3-(2-fluorenyl)-D,L-alanyl, and 3-(Het)-D,L-alanyl wherein Het is a heterocyclic aryl containing radical selected from
wherein A" and A' are independently selected from the group consisting of hydrogen, lower alkyl, chlorine and bromine, and G is selected from the group consisting of oxygen, nitrogen and sulfur;
B is an amino acyl residue selected from the group consisting of D-phenylalanyl, D-p-Cl-phenylalanyl, D-p-F-phenylalanyl, D-p-nitrophenylalanyl, 3-(3,4,5-trimethoxyphenyl)-D-alanyl, 2,2-diphenylglycine, D-a-methyl-p-Cl-phenylalanine and 3-(2,4,6-trimethylphenyl)-D-alanyl;
C is an amino acyl residue selected from the group consisting of L-tryptophanyl, D-tryptophanyl, D-phenylalanyl, D-Me s phenylalanyl, 3-(2-pyridyl)-D-alanyl, 3-(3-pyridyl)D-alanyl, 3-(1-naphthyl)-D-alanyl, 3-(2-naphthyl)-D-alanyl and 3-(4-pyridyl)-D-alanyl.
D is an amino acyl residue selected from the group consisting of L-seryl, and D-alanyl;
E is an amino acyl residue selected from the group consisting of L-phenylalanyl and L-tyrosyl;
F is an amino acyl selected from the group consisting of the radicals represented by the following structural formulas:
wherein

n is 1 to 5 ;
R, is alkyl of 1 to 12 carbon atoms, -NRR 3 wherein R is hydrogen or alkyl of 1 to 4 carbon atoms, R 3 is alkyl of 1 to 12 carbon atoms, cycloalkyl, phenyl, benzyl, -(CH 2 ) n -morpholino or -(CH 2 ) n N(R 4 ) 2 wherein n is 1 to 5 and R 4 is lower alkyl;
R 2 is hydrogen or R 3 ; or R, and R 2 comprise a ring represented by the following structural formulas:
wherein n is 1 to 7; A is hydrogen, alkyl of 1 to 6 carbon atoms or cycloalkyl; and X is halo or A or b) H 2 N-CH-CO 2 H
wherein R 5 is alkyl of 1 to 6 carbon atoms, benzyl, phenylethyl, cyclohexyl, cyclopentyl; and R 6 , R 7 and R 8 are hydrogen or alkyl of 1 to 4 carbon atoms; and n is the integer 2-5; or
C) a substituent of the formula
wherein R 9 is hydrogen, alkyl of 1 to 12 carbon atoms, phenyl or phenylloweralkyl;
G is an amino acyl residue selected from the group consisting of L-leucyl, L-norleucyl and L-norvatyl;
H is D-alaninamide, D-leucinamide, glycinamide or -NHR 5 wherein R 5 is lower alkyl, cycloalkyl, fluoro lower alkyl, or NHCONH-R 10 wherein R, o is hydrogen or lower alkyl; and the pharmaceutically acceptables salts thereof.