(8S)-8-[(1,1-Dimethylethoxy)carbonyl]-12,12-dimethyl-10-oxo-3-thioxo-11-oxa-2,4,9-triazatridecanoic Acid Phenylmethyl Ester is an intermediate in the synthesis of Arginino-succinic Acid Disodium Salt (A769200). Arginino-succinic Acid Sodium Salt is used in the characterization of δ-crystallin in avian species.