Abstract: The present application discloses a process for the conversion of penicillin-1-(R)-sulfoxide(s) and/or cephalosporin-1-(R)-sulfoxides in solution, to their corresponding 1-(S)-sulfoxides comprising the step of treating said 1-(R)-sulfoxide with a sufficient amount of an acid anhydride to convert at least some of said 1-(R)-sulfoxide to its corresponding 1-(S)-sulfoxide. Also disclosed is a process for the production of 1-(S)-sulfoxide from penicillin and/or cephalosporin by oxidizing the penicillin or cephalosporin with an oxidizing agent and simultaneously or subsequently adding a sufficient amount of an acid anhydride to convert at least some 1-(R)-sulfoxide to its corresponding 1-(S)-sulfoxide over a time period of from 5 minutes to 2 hours so as to maintain the pH above 3.5 and produce a solution of the corresponding 1-(S)-oxide. In a preferred embodiment, a buffer is incorporated in the solution to provide additional pH control during the reaction.

Abstract: A polymerizable or copolymerizable unsaturated polyester composition contains a peroxide initiator and a compound of the formula: ##STR1## wherein Y is hydroxy, alkoxy having 1-12 carbon atoms, or alkyl having 1-12 carbon atoms, and Z is hydrogen, hydroxycarbonyl, alkyl, cycloalkyl, aralkyloxycarbonyl having 1-20 carbon atoms, benzoyl, or alkanoyl having 1-4 carbon atoms.