Novel alkoxylations of cephalosporins by cerium(IV) salts and by electro-oxidative procedures
Abstract
Electrolyses of cephalosporins in methanol–tetrahydrofuran mixtures in the presence of tetraethylammonium tosylate provide useful syntheses of the corresponding 2-methoxy derivatives [(2), (3b), and (6)]. The same derivatives are produced when the cephalosporins are treated with cerium(IV) ammonium nitrate (CAN) in methanolic tetrahydrofuran. Alkoxylations of the cephalosporin (1) by CAN or by the electro-oxidative procedure, in the presence of ethanol, propan-2-ol, or benzyl alcohol, lead to the corresponding 2-ethoxy (7a), 2-isopropoxy (7b), and 2-benzyloxy derivatives.