Enzymatic synthesis of .beta.-lactam antibacterials

A process for the synthesis of a penicillin or cephalosporin comprising the steps of:

• subjecting an amine of the formula:
• H.sub.2 N--Q
• optionally in an enzymatically acceptable conventional salt or ester form to enzymatic catalysis in the presence of an acylase and in the presence of an ester of the formula:
• ##STR30## wherein Q is a group of the formula:
• ##STR31## Z is hydrogen, halogen, or a group which consisting of 1 to 7 carbon atoms selected from the group consisting of methyl, lower alkoxy, monocyclic (O, N or S)-heterocyclic thio, monocyclic lower aralkyl, lower alkanoyloxy, lower alkanoyloxy-lower alkyl, monocyclic (O, N or S)-heterocyclic thio-lower alkyl, or pyridinium-lower alkyl, optionally substituted with lower alkyl, carboxy-lower alkyl, lower alkoxy, carbamoyl or halogen;
• RCO, which contains 1 to 15 carbon atoms, is lower alkanoyl, lower alkenoyl, monocyclic lower aralkanoyl, monocyclic aryloxylower alkanoyl, (O, N or S)-heterocyclic-lower alkanoyl, (O,N or S)-heterocyclic thio-lower alkanoyl, cyanoacetyl, cyanomethylthioacetyl, monocyclic arylglycyl, monocyclic cycloalkenylglycyl, monocyclic arylglycolyl, N-acylarylglycyl, monocyclic arylmalonyl or arylsulfoalkanoyl, optionally substituted with lower alkyl, aminomethyl, halogen, hydroxy, lower alkanoyloxy or lower alkoxy;
• X is hydrogen, lower alkyl or hydroxymethyl;
• Y is hydrogen or lower alkyl;
• and n is an integer of from 1 to 20, to form a penicillin or cephalosporin of the formula:
• RCONH--Q
• wherein R and Q are as defined above.