Chemical and biological reactivity of sulfamidopenicillins

Abstract

A number of semisynthetic penicillins bearing a sulfamido side chain at the 6-position have been prepared and their chemical and biological reactivity examined. The compounds do not show antibiotic activity against Escherichia coli but do show activity against Staphylococcus aureus. The rates of hydroxide-ion catalysed hydrolysis correlate well with the inductive effect of the sulfamido group indicating no pronounced steric effect on the chemical reactivity of the β-lactam ring. Molecular modelling studies show that the sulfamido group does not have an effect on the ‘open’versus‘closed’ conformations of the thiazolidine ring different from that of the benzylamido group. Comparisons with some sulfonamidopenicillins are made.