NEW PROCESS FOR PREPARING AN OCTAPEPTIDE

An octapeptide, endowed with thymic humoral activity, of the formula (A): H-Leu-Glu-Asp-Gly-Pro-Lys-Phe-Leu-OH and pharmaceutically acceptable salts thereof are prepared by condensing a compound of the formula (B) X-Leu-G @u-A@p-Gly-K wherein X is an amino protecting group, Y and Y min are each optional and each independently represents a carboxy protecting group and K is a hydroxy or hydrazido group, with a compound of formula (C): H-Pro-L @s-Phe-Leu-Q (C) wherein W is an amino protecting group and Q represents a carboxy protecting group or a hydroxy group deprotecting the resultant compound of the formula (D) X-Leu-G @u-A@p-Gly-Pro-L @s-Phe-Leu-Q (D) wherein X,Y,Y min ,W and Q are as defined above; and, if desired, converting the resulting peptide of formula (A) into a pharmaceutically acceptable salt thereof.