Design,synthesis, and biological evaluation of a series of beta-lactam-based prodrugs

By use of pro-dual-drug concept the synthesis of 6-beta-(R)-2-(clavaminio-9-N-yl)-2-(4-hydroxyphenylacetamido)]penicillanic acid (10), 6-beta-(R)-2-(amino)-2-(4-(clavulano-9-O-yl)phenylacetamido)]penicillanic acid (13), (Z)-4-2-(amoxycillin-4-O-yl)ethylidene]-2-(clavulano-9-O-yl)-3-methoxy-Delta(alpha,beta)-butenolide (19), and 3-(amoxicillin-4-O-yl)methyl]-7-(phenoxyacetamido)-(1-oxo)-3-cephem-4-carboxylic acid (23) was accomplished. Unlike penicillin G, ampicillin, or amoxicillin, these four heretofore undescribed compounds 10, 13, 19, and 23 showed notable activity against beta-lactamase (betaL) producing microorganisms, Staphylococcus aureus A9606, S. aureus A15091, S. aureus A20309, S. aureus 95, Escherichia coli A9675, E. coli A21223, E. coli 27C7, Pseudomonas aeruginosa 18S-H, and Klebsiella pneumoniae A20634 TEM. In comparison with amoxicillin (9), alpha-amino-substituted compound 10 and butenolide derivative 19 showed a broadened spectrum of antibacterial activity; yet they were found to be less active than 13 and 23. Like clavulanic acid (7) or cephalosporin-1-oxide (21), the newly synthesized compounds 10, 13, 15, 16, 19, or 23 functioned as potent inhibitors of various bacterial betaLs.