Synthesis of new penicillin derivatives as drug-like molecules for biological screening

Chemical modification of penicillin β-lactam ring was made. Six thiazolidine amides were produced through N4-C7 β-lactam ring opening of penicillin V methyl ester with various aliphatic, aromatic, and heterocyclic primary amines. Five 8-hydroxypenillic acid derivatives with side chains of methyl, propyl, benzyl, and diethylaminoethyl groups were yielded via β-lactam ring rearrangement from 6-aminopenicillanic acid (6-APA). Parallel synthetic methods were used for the alkylation of 8-hydroxypenillic acid and β-lactam ring opening of penicillin V methyl ester. The biological activities of the compounds were evaluated.