Synthesis of 5-Thienylfuran-3(2H)-ones via the Microwave-Assisted Tandem Reaction of Cyanopropargylic Alcohols with Thiophene-2-carboxylic Acids
摘要:
Tertiary cyanopropargylic alcohols undergo tandem reaction with thiophene-2-carboxylic and benzo[b]thiophene-2-carboxylic acids under microwave irradiation (MeCN, Et3N, 100 degrees C, 2.5-16 h) to afford 4-cyano-5-thienylfuran-3(2H)-ones in 69-89%. The cyano function of the synthesized furanones is readily hydrolyzed (aq EtOH, KOH, 20-25 degrees C, 24 h) to give quantitatively the corresponding amides, 5,5-dialkyl-4-oxo-2-(2-thienyl)-4,5-dihydrofuran-3-carboxamides.
Abstract 5-Alkyl/aryl/hetaryl-4-cyano-3(2H)-furanones undergo ring-cleavage/recyclization in the presence of water under mild conditions [MOH (M = Na, K), aqueous ethanol, 20–25 °C] to afford 4-acyl/aroyl/hetaroyl-5-amino-3(2Н)-furanones in 75–99% yields. 5-Alkyl/aryl/hetaryl-4-cyano-3(2H)-furanones undergo ring-cleavage/recyclization in the presence of water under mild conditions [MOH (M = Na, K)