Synthetic Studies on Novel β-Lactam Compounds from L-Aspartic Acid

Abstract

The optically active monocyclic β-lactams 1 were synthesized from L-aspartic acid α-benzyl ester by the four-component-condensation method. The conversion of the amides 1 to the corresponding methyl esters 2 were accomplished via imino chlorides. The tricyclic β-lactam 4 and 5 were prepared by intramolecular Friedel-Crafts acylation, whose ketone groups were reduced to the methylene analogues 8 and 10, respectively. Further transformation of the furan derivative 10a to a bicyclic 1-carbacephem compound 12 by oxidative ring cleavage was also investigated.