SYNTHESIS OF N-ALKOXYCARBONYL-3-SUBSTITUTED TETRAMIC ACIDS AND FUNCTIONALIZED ENOLS VIA C-ACYLATION REACTIONS OF ACTIVE METHYLENE-COMPOUNDSWITH N-HYDROXYSUCCINIMIDE ESTERS OF N-ALKOXYCARBONYL-ALPHA-AMINO ACIDS

The N-hydroxysuccinimide esters of N-alkoxycarbonyl-alpha-amino acids react with active methylene compounds (malonic and acyl acetic esters) ,under basic conditions, to produce N-alkoxycarbonyl-3-substituted tet ramic acids 7-17; in the case of the N-hydroxysuccinimide ester of L-a lanine, the corresponding optically active tetramic acids 15 and 16 ar e obtained. In addition, the C-acylation reactions of cyanoacetic este rs furnishes the functionalized enols 18-23 in very good yields. Spect ral data and physical characteristics for all compounds:are reported.