Synthesis and structure-activity relationships in the cefpirome series. II. Analogues of cefpirome with different 7-heteroarylacetamido and 3'-ammonium substituents.

The synthesis and antibacterial activity in vitro of 7-(2-heteroarylacetamido)-3-[(2,3- cyclopentenopyridinium)methyl]cephalosporins and of some related compounds with different ammonium functions in 3'-position are described. The 7-[5-amino-1,2,4-thiadiazol-3-yl] and the 7-[4-aminopyrimidin-2-yl] analogues of cefpirome and compounds with 3-aliphatic ammoniummethyl functions have excellent antibacterial activity. Cephalosporins with different N-heterocycles other than pyridine in 3'-position are less active than their 3-pyridiniummethyl analogues.

Synthesis and structure-activity relationships in the cefpirome series. I. 7-[2-(2-Aminothiazol-4-yl)-2-(Z)-oxyiminoacetamido]-3-[(su bstituted-1-pyridinio)methyl]ceph-3-em-4-carboxylate s.

7-[2-(2-Aminothiazol-4-yl)-2-(Z)-oxyiminoacetamido]-3-[(s ubs tituted-1-pyridinio)methyl]ceph-3-em-4-carboxylates II are a group of beta-lactam antibiotics with extraordinary high antibacterial activity. The promising member of this group, cefpirome (HR 810, II-1) is a candidate for clinical use. Synthetic pathways to II starting from cefotaxime derivatives I or 7-aminocephalosporanic acid (7-ACA) are described.