Connlab Holdings Limited

Nicholas Darby

Peter K Wolfert

A process for preparing 2-acyloxymethylpenams and 3-acyloxycephams of the formulae 1 and 2 ##STR1## in which R represents the aliphatic, aromatic, or heterocyclic moiety of an amino-protecting group commonly employed in penicillin chemistry, R.sup.1 is hydrogen or represents a carboxy-protecting group commonly employed in penicillin chemistry, and R.sup.2 is hydrogen, C.sub.1 -C.sub.6 alkyl which may also be substituted with Cl, OCH.sub.3, or CN, and phenyl which may also be substituted with CH.sub.3, F, Cl, OCH.sub.3 or NO.sub.2, by treating an unsym-azetidinone disulfide of the formula 3 ##STR2## in which R and R.sup.1 are as defined above and R.sup.4 is benzothiazol-2-yl or benzoxazol-2-yl with silver oxide, an acid of the formula R.sup.2 COOH, and iodine, or with a silver salt of the formula R.sup.2 COOAg and iodine, or with a Simonini complex of the formula R.sup.2 COOI.R.sup.2 COOAg, to obtain a mixture of the compounds of formulae 1 and 2, and optionally separating said mixture.

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Edmonton, Canada

Nicholas Darby