Hydrochloric Acid → Thieno(2,3-b)pyridine

Participants

Reaction Conditions

Reaction Steps

To a vigorously stirred mixture of 2-nitrothiophene (J-1) (13 g, 0.1 mol) and concentrated hydrochloric acid (195 mL) was added tin (25 g) at 0° C. After most of the tin was dissolved, EtOH (70 mL) and anhydrous ZnCl2 (6 g) were added. The mixture was heated to 85° C., and then treated with malonaldehyde bis(diethyl acetal) (17.2 g, 0.078 mol) in EtOH (30 mL). The resulting reaction was maintained at 85° C. for 1 h, then poured onto ice (100 g), basified with NH3.H2O, and extracted with DCM (75 mL×3). The combined organic layers were concentrated and purified by chromatography on silica gel to give the title compound. MS (m/z): 135 (M)+.

Provenance & Evidence