Pyridine → 7-oxo-7H-thieno[3,2-b]pyridine-4,6-dicarboxylic acid 6-ethyl ester 4-isopropyl ester

Participants

Reaction Steps

Add pyridine (1.20 ml, 14.8 mmol) to a suspension of 7-hydroxy-thieno[3,2-b]pyridine-6-carboxylic acid ethyl ester (1.10 g, 4.93 mmol) in dichloromethane (50 ml), and then add isopropyl chloroformate (1.0 N in toluene, 14.8 ml). Stir the reaction mixture at room temperature overnight. Wash the mixture with 1 N HCl (50 ml) followed by brine (3×50 ml). Separate the organic layer, dry over sodium sulfate, filter and concentrate. Purify using silica gel column chromatography (gradient eluent, 0-60% ethyl acetate in hexane) to provide 7-oxo-7H-thieno[3,2-b]pyridine-4,6-dicarboxylic acid 6-ethyl ester 4-isopropyl ester (1.37 g, 90%) as a white crystalline solid. MS (ES+): 310 (M+H).

Provenance & Evidence