Mfg. antibiotic cephem cpds. by acylation using reactive ester(s)

摘要

A cephem cpd. of the formula (I) is prepd. by esterifying an acid having the formula (II) with a cpd.having the formula (IV) in the presence of an organic amine to give a reactive ester of the formula (V) and then reacting this with an amine of the formula (II) in an organic solvent. R1 = H or alkali metal; R2 = H, acetoxymethyl or 5- or 6-membered ring heterocyclyl; R3 = benzotriazolyl, pyridyl, succinimidyl or phthalimidyl. n = 1 or 2.