Synthetic studies on 1,2-dehydro-1-carbacephem compounds.

Abstract

7-Azido-1, 2-dehydro-1-carbacephem 13 was efficiently synthesized by employing ketene-imine cycloaddition, intramolecular Horner-Emmons reaction and elimination of a phenylsulfoxide group or an ammonium group. 7-Acylamino 1, 2-dehydro-1-carbacephems, 18 and 19, were obtained from 13. Infrared absorption frequencies of the β-lactam carbonyl in 1, 2-dehydro-1-carbacephem compounds thus prepared are equal to or higher than those of the corresponding 1-carbacephem compounds. However, 18 and 19 exhibited very poor antibacterial activity.