Synthesis of 1-carbacephem derivatives.

Abstract

Total syntheses of several types of racemic 1-carbacephem derivatives, 30, 32, 35, 37, 39, 45, 46, 50, 56, 57, 58, 65, and preliminary biological results are described. Addition of azidoacetyl chloride to the Schiff base 10 in the presence of triethylamine gave cis-azetidinones 11a, b which were converted to the racemic key intermediate 5. By applying sequences of reactions developed in 1-oxacephem syntheses, various kinds of 1-carbacephems were prepared from 5. Among twelve derivatives prepared, 50 showed the highest antibacterial activity.