Acetic Anhydride → 2,3-Dihydro-4H-thiopyrano[2,3-b]pyridin-4-one

Participants

Reaction Steps

A solution of 14 g. (61.6 mmol) 3-(3-Carboxy-2-pyridylthio)propionic Acid [prepared as described in lit.: J. Heterocyclic Chem., 37, 379 (2000)] and 15 g. (185 mmol, 3 eqs) of anhydrous sodium acetate, in 200 mL. of acetic anhydride was refluxed (160° C.) under stirring, N2 atm, dry conditions, for 2 hours. Cooled, diluted with 300 mL of water, basified with 30% ammonium hydroxide solution to pH 8-9, extracted with 3×200 mL chloroform. Combined organics washed with 2×60 mL Sodium bicarbonate (satn.sol), water, dried, evaporated, gave 2.8 g. (27%) of the title compound, reddish solid, m.p. 66-8° C., (M+H)+=166.2.

Provenance & Evidence