2-AMINO-5,6-DIHYDRO-4H-CYCLOPENTA[B]THIOPHENE-3-CARBOXYLIC ACID ETHYL ESTER

120-92-3

105-56-6

4815-29-6

GENERAL METHOD: Cyclopentanone (1.06 mL, 10 mmol), ethyl cyanoacetate (1.15 mL, 10 mmol), morpholine (0.90 mL, 10 mmol), and sulfur powder (0.32 g, 10 mmol) were dissolved in ethanol (10 mL) with stirring and refluxed overnight. Upon completion of the reaction, the reaction mixture was cooled to room temperature and the solvent was subsequently removed under vacuum. The crude product was washed with cold ethanol, filtered through a sintered funnel and dried under vacuum. The dried crude product was dissolved in dichloromethane and washed with brine. The organic layer was separated and concentrated under low vacuum to afford the target compound ethyl 2-amino-5,6-dihydro-4H-cyclopenta[b]thiophene-3-carboxylate (2a), yield: 73% (1.83 g).