Methy (3S,8S,9S)-3-(1,1-Dimethylethyl)-8-hydroxy-13,13-dimethyl-4,11-dioxo-9-(phenylmethyl)-6-[[4-(2-pyridinyl)phenyl]methyl]-12-oxa-2,5,6,10-tetraazatetradecanoic Acid Ester is an intermediate used in the synthesis of Atazanavir-d9 (A790053), which is the deuterated analog of Atazanavir (A790051), a azapeptide HIV protease inhibitor derivative. Atazanavir have been investigated as potential treatment of human immunodeficiency virus (HIV) and for anticancer purposes.