Ammonium Chloride → 5-ethyl-7-oxo-6,7-dihydro-5H-thieno[3,2-b]pyridine-4,6-dicarboxylic acid 6-ethyl ester 4-isopropyl ester

Participants

Reaction Conditions

Reaction Steps

Mix 7-oxo-7H-thieno[3,2-b]pyridine-4,6-dicarboxylic acid 6-ethyl ester 4-isopropyl ester (0.512 g, 1.66 mmol) and copper(I) iodide (0.695 g, 3.65 mmol) in THF (35 ml). Cool the mixture to −78° C. Inject ethyl magnesium bromide (3.0 M in diethyl ether, 1.66 ml) and stir for 1.5 h. Add another portion of ethyl magnesium bromide (3.0 M in diethyl ether, 3.30 ml) and keep the reaction at −78° C. for one more hour. Warm up to −20° C. overnight in a freezer. Pour the reaction mixture into saturated ammonium chloride solution (200 ml). Extract with ethyl acetate (3×200 ml). Combine all the organic layers, dry over Na2SO4, filter and concentrate to give 5-ethyl-7-oxo-6,7-dihydro-5H-thieno[3,2-b]pyridine-4,6-dicarboxylic acid 6-ethyl ester 4-isopropyl ester (0.520 g, 93%) as a crude oil. MS (ES+): 340 (M+H).

Provenance & Evidence