Protection of carboxyl gps. in penicillin and cephalosporin synthesis

摘要

Temporary protection of COOH groups by conversion into -COOCH2CCl3 groups, the COOH group subsequently being released by treating with chemical reducing agents (e.g. nascent hydrogen, alkali or alkaline earth metals in liquid NH3, or strongly reductive metal salts (e.g. CrII cpds.). Temporary protection of COOH groups in preparative chemistry and during degradation reactions. The 2, 2, 2-trichloroethyl protecting group is readily, but specifically removable by treatment with chemical reducing agents, but is resistant and inert to a wide variety of other reaction conditions. Reactions on the ester group itself (e.g. re-esterification etc. of the COOCH2CCl3 group) can, however, be carried out.