Studies on penam sulfones III. Synthesis and β-lactamase inhibitory activity of sodium (6R)-6-(α-hydroxybenzyl)-2β-methoxyiminomethyl-2α-methylpenam-3α-carboxylate 1,1-dioxide and sodium 2β-acyl-2α-methylpenam-3α-carboxylate 1,1-dioxide

The synthesis and in vitro synergies of (6R)-6-(α-hydroxybenzyl)-2β-methoxyiminomethyl-2α-methylpenam-3α-carboxylate 1,1-dioxide (4) and 2β-acyl-2α-methylpenam-3α-carboxylate 1,1-dioxide (15) are described. Compound 15 showed good in vitro synergy in combination with piperacillin and ceftazidime against chromosomally mediated class I cephalosporinase producing organisms including TEM, SHV, and OXA-type enzymes producing microorganisms.