摘要:
AbstractThe chemical resolution of γ,γ′‐di‐t‐butyl DL‐N‐benzyloxycarbonyl‐γ‐carboxy‐glutamate is described in detail (preliminary account see [1]). The D (−)‐derivative was obtained as a crystalline quinine salt, and the L (+)‐derivative as a crystalline salt with (−)‐ephedrine in yields of 44 and 70%, respectively. Physical data are indicated for the enantiomers of γ,γ′‐di‐t‐butyl N‐benzyloxycarbonyl‐γ‐carboxyglutamate, γ,γ′‐di‐t‐butyl γ‐carboxyglutamate, and γ‐carboxyglutamic acid. The absolute configurations and optical purities of the γ,γ′‐di‐t‐butyl (+)‐ and (−)‐N‐benzyloxycarbonyl‐γ‐carboxyglutamates were determined by removal of the protecting groups and decarboxylation to optically active glutamic acid.