Cetrorelix Impurity 27

AC-3- (2-naphthyl) -D-Ala-4-Cl-D-Phe-3- (3-Pyridyl) -D-Ala-Ser-Tyr-D-Cit-Leu-Arg-Pro-NH2; (S) -1- (N2- (L-leucyl) -N2- ((R) -2- ((S) -2- ((S) -2- ((R) -2- ((R) -2- ((R) -2-acetamido-3- (naphthalen-2-yl) propanamido) -3- (4-chlorophenyl) propanamido) -3- (pyridin-3-yl) propanamido) -3-hydroxypropanamido) -3- (4-hydroxyphenyl) propanamido) -5-ureidopentanoyl) -L-arginyl) pyrrolidine-2-carboxamide