Synthesis of methyl 3-amino-4-aryl(or methyl)sulfonyl-2- thiophenecarboxylates from 3-alkoxy-2-aryl(or methyl)-sulfonylacrylonitriles

The synthesis of a series of methyl 3-amino-4-aryl(or methyl)sulfonylthiophene-2-carboxylates by reaction of 3-alkoxy-2-aryl(or methyl)sulfonylacrylonitriles with methyl thioglycolate in the presence of triethylamine is described. Hydrolysis/decarboxylation of the ester at the 2- position and acylation of the resulting amine represents a convenient route to 4-arylsulfonyl-3-carboxamidothiophenes. Attempted acylation of a title aminothiophene under standard conditions was unsuccessful.