Semisynthetic beta-lactam antibiotics. I. Synthesis and antibacterial activity of new ureidopenicillin derivatives...

The synthesis and antibacterial activity of new ureidopenicillin derivatives having catechol moieties in the 6-acyl side chain are described. These compounds showed remarkably strong activities against Pseudomonas aeruginosa. Especially, 6-[(R)-2-[3-(3,4-dihydroxybenzoyl)-3-methyl-1-ureido]-2- phenylacetamido]penicillanic acid (7a) had the most potent activity in vitro against Gram-negative bacteria, its activity being 30 approximately 60-fold greater than that of piperacillin against most strains of P. aeruginosa.