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

On alkylation of K 14 CN with the methyl ester of L‐α‐benzyl‐oxycarbonylamino‐γ‐bromobutyric acid, the methyl ester of L‐α‐benzyloxycarbonylamino‐γ‐cyano‐ 14 C‐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‐ 14 C in one reaction step. L‐Ornithine‐5‐ 14 C was prepared by catalytic hydrogenation of the nitrilo ester II, and L‐glutamic‐5‐ 14 C 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.