Abstract
Methyl 3-methyl-7β-benzamido-3-cephem-4-carboxylate (1) and t-butyl 3, 4_??_-dimethyl-7β-pivalamido-7α-methylthio-2-cephem-4-carboxylate (7) were treated with triphenylmethyl tetrafluoroborate. 1 gave mainly 2-phenyl-4-triphenylmethyl-2-oxazolin-5-one (2), (Z)-methyl 2-formamido-3-methyl-4-triphenylmethylthio-2-butenoate (3), 2-triphenylmethyl benzoylglycine (4) and bis ((Z)-3-formamido-3-methoxycarbonyl-2-methyl-2-propene) disulfide (5). 7 gave methyl triphenylmethyl sulfide (8), 2-t-butyl-4-triphenylmethyl-4-methylthio-2-oxazolin-5-one (9) and 4-t-butoxycarbonyl-4, 5-dimethyl-4H-1, 3-thiazine (10). This reveals that triphenylmethyl cation cleaves the C6-C7 and N5-C8 bonds of cephem derivatives.
