Hydrochloric Acid → Ethyl furo[3,2-b]pyridine-6-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of conc. hydrogen chloride (100 mL) containing zinc chloride (11.6 g, 83 mmoL) was added 3-(t-butoxycarbamoyl)furan (13.8 g, 75.4 mmol). After stirring for 5 minutes, the reaction mixture was diluted with ethanol (60 mL) and a solution of ethoxycarbonylmalonaldehyde (11.6 g, 80.6 mmol) in ethanol (40 mL) was added. This mixture was warmed at 80° C. for two hours and then cooled and poured into ice/water and made basic with ammonium hydroxide. The product was extracted into methylene chloride, dried over anhydrous sodium sulfate, filtered through a pad of charcoal and evaporated. This residue was chromatographed on silica gel eluting with chloroform to give 5.92 g of purified product. Crystallization from hexane provided product with, mp: 63°-65° C.

Provenance & Evidence