Efficient Synthesis of Highly Substituted Furan, Thiophene, Pyrrole and 2‐Aminothiazole Derivatives

Abstract

Ethyl cyanoacetate dimer (1) undergoes bromination with N‐bromosuccinimide (NBS) to afford 3‐amino‐4‐bromo‐2‐cyano‐pent‐2‐enedioic acid diethyl ester (2). This bromo derivative reacts with potassium carbonate, sodium hydrogen sulfide, aromatic amines, ammonium thiocyanate, thiourea, N‐phenylthiourea, and thiosemicarbazide to afford highly substituted furan, thiophene, pyrrole, and 2‐aminothiazole derivatives. Mechanistic explanations as well as structure elucidations are discussed.

Keywords:

• 2‐aminothiazole derivatives
• ethyl cyanoacetate dimer
• furan‐2,4‐dicarboxylic acid diethyl ester
• N‐substituted pyrrole
• thiophene‐2‐carboxylic acid ethyl ester