PROCESS FOR PREPARING CEPHALOSPORIN ANTIBIOTICS

摘要

Cephalosporins I (Ra,Rb = C1-4 alkyl, forms C3-7 cyclo-alkylidene with C; R4 = H, 3-or 4-carbamoyl; B =>S or >S→O; R5a = -COOθ, -COOR5; R5 = carboxyl protecting group; R6 = H, carboxyl protecting group; R7 = amino; R6a = carboxyl protecting group) and their salts were prepd. Thus, (6R,7R)-7-≮(Z)-2-(2-aminothiazol-4-yl)-2-(1-carboxycyclopent-1-yl-oxyimino)-acetamido≉-3-(1-pyridiniummethyl)-ceph-e-em-4-carboxylate dihydrochloride salt was prepd. from (Z)-2-(1-tert.-butoxycar-bonylcyclopent-1-yl-oxyiminotritylamino)-2-(2-tritylaminothiazol-4-yl) acetic acid.