Reactions of benzotriazoles with diethyl ethoxymethylenemalonate; ethylation and michael addition. Comparison with other esters andN-heterocycles

Benzotriazole and its 5-methyl-and 5-nitro derivatives react with diethyl ethoxymethylenemalonate by ethylation at each of the ring N-atoms and through Michael addition, to give the isomeric esters ethyl (E/Z) 3-[5(6)-R-benzotriazol-1-yl]propenoates. Benzotriazole and its 5-nitro derivative react similarly with ethyl acetoacetate but N-ethyl derivatives are obtained in lower yields. Other 1,2,3-triazoles derivatives and indole were ineffective in this reaction while benzimidazole produced similar results but accompanied with a small amount of a benzimidazoline addition product, whose structure has been determined by crystallo-graphic analysis.