beta-lactam antibiotics derived from nitrogen heterocyclic acetic acids. 2. Cephalosporin derivatives

Three cephalosporin derivatives were prepared from 1,4-dihydro-4-oxypyridine-1-acetic acid. These were the 7-aminocephalosporanic acid (7-ACA) derivative and the compounds with 5-methyl-1,3,4-thiadiazol-2-thiol and 1-methyl-1,2,3,4-tetrazole-5-thiol at C-3 of the cephalosporin nucleus. The antibacterial activity of the 7-ACA derivative was comparable to cephalothin, and that of the other two derivatives was comparable to cefazolin. The 7-ACA derivative, compared to cephalothin, was significantly less metabolized, was less protein bound, and had a longer half life.