Nitrosation of methyl 2-cinnamoylamino-3-dimethylaminopropenoates. Alkyl N-cinnamoyloxalic acid hydroxyimidic amides, intermediates in the synthesis of alkyl 5-styryl-1,2,4-oxadiazole-3-carboxylates

Alkyl 2-(substituted cinnamoylamino)-3-dimethylaminopropenoates 5, prepared either from glycine (1) and substituted cinnamoyl chlorides 2 via oxazol-5(4H)-ones 4, or from cinnamoylglycinate with t-butoxybisdimethylaminomethane, were transformed by nitrosation into 5-substituted-1,2,4-oxadiazole-3-carboxylates 8. The formation of alkyl N-cinnamoyloxalic acid hydroxyimidic amides 7, which were isolated as intermediates, represent a novel synthesis of N-acyl substituted hydroxyimidic amides.