METHOD OF PRODUCING PENEM COMPOUNDS

New antibacterial agents are compounds of formula wherein R is hydrogen atom or C1-C4 alkyl group optionally substituted from halogen atom or hydroxy group optionally protected, A is Z, ZOCO or ZCO residue, wherein Z is phenylene, naphthylene, heterocyclediyl, C1-C7 alkylene, C2-C4 alkenylene, alkynylene, , C3-C8 cycloalkylene, aralkylene radical optionally substituted, and Q represents a group , wherein R1, R2 and R3 are each either: (i) optionally substituted alkyl, aralkyl or aryl radical or (ii) R1 is as defined above under (i) and R2, R3, taken together, represent an optionally substituted or fused heterocyclic radical or (iii) R1, R2, R3 taken together, represent an optionally substituted azonia-bicyclo or tricyclo radical or (iv) R1, R2, R3, taken together, represent an optionally substituted or fused pyridinium, pyrazinium, pyrazolium or pyridazinium radical, and the pharmaceutically or veterinarily acceptable salts thereof. The compounds are prepared by reacting the amine NR, R R with the corresponding penem substituted in the s positions by A-HC2-L group where A is as defined above and L is a leaving group.