Efficient syntheses of ethyl 4-cyano-5-hydroxy-2-methyl-1H-pyrrole-3-carboxylate and ethyl (2Z)-(4-cyano-5-oxopyrrolidin-2-ylidene)ethanoate

Active methylenes in the synthesis of a pyrrole motif: an imperative structural unit of pharmaceuticals, natural products and optoelectronic materials

“…Triethylamine catalyzed synthesis of novel 4-cyano-5hydroxy-2-methyl-1H-pyrrole-3-carboxylate from 2-cyanoacetamide has been discussed by P. B. S. Dawadi and J. Lugtenburg (Scheme 15). 72 The reaction of ethyl 2-chloroacetoacetate with 2cyanoacetamide in the presence of a non-nucleophilic base, triethylamine in stoichiometric amounts, afforded C-alkylation product ethyl 4-cyano-2-hydroxy-2-methyl-5-oxopyrrolidine-3carboxylate 48, followed by its p-toluenesulfonic acid-catalyzed dehydration to obtain 4-cyano-5-hydroxy-2-methyl-1H-pyrrole-3-carboxylate in 81% yield. This work enables access to libraries of biologically signicant pyrrole derivatives from commercially available starting materials.…”

2-Cyanoacetamide

“…4 (C) The triethylamine-catalyzed alkylation of 2-cyanoacetamide (1) with 2-chloroacetoacetate (9) followed by nucleophilic attack of the amide nitrogen on the carbonyl group and acid-catalyzed dehydration led to the formation of substituted pyrrole 10 in good yield. 5 …”