Synthesis and antimicrobial activity of pyrimidinylureidocephalosporins

The synthesis of a series of 7R-[(R)-2-[3-[5-pyrimidinyl]ureido]-2-(aryl)acetamido]-3-cephem-4- carboxylates is described. Variation of the substituents at the 3-position in the cephem nucleus, at the 2-position of the pyrimidine ring, and of the phenyl residue in the acyl side chain is carried out. Qualitative structure-activity relationships in this series are discussed. VX-VD 2, the most interesting compound, exhibits broad antimicrobial activity against Gram-negative bacteria, including Pseudomonas aeruginosa.