Synthesis of L‐glutamine‐S‐14C, L‐glutamic acid‐5‐14C, and L‐ornithine‐5‐14C

Abstract
On alkylation of K14CN with the methyl ester of L‐α‐benzyl‐oxycarbonylamino‐γ‐bromobutyric acid, the methyl ester of L‐α‐benzyloxycarbonylamino‐γ‐cyano‐14C‐butyric acid (II) was obtained The latter was submitted to mild alkaline hydrolysis to yield the free nitrilo acid III which on treatment with hydrogen bromide solution in acetic acid gave L‐glutamine‐5‐14C in one reaction step. L‐Ornithine‐5‐14C was prepared by catalytic hydrogenation of the nitrilo ester II, and L‐glutamic‐5‐14C acid was obtained on acid hydrolysis of the same compound (II). The activated ester (2, 4, 5‐trichlorophenyl ester) of acid III may serve as a suitable intermediate for the preparation of glutamine or ornithine peptides. All prepared substances were optically active L‐forms.