Water → 3,4,5,6,7,8-Hexahydrobenzo[4,5]thieno[2,3-c]pyridin-1(2H)-one

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Reaction Conditions

Reaction Steps

A 50-mL single-neck round-bottomed flask equipped with a reflux condenser, magnetic stirrer and nitrogen inlet was charged with 105d (285 mg, 1.38 mmol) and polyphosphoric acid (15 g). After stirring at 80° C. for 16 h, the reaction mixture was cooled to room temperature, and water (30 mL) was added. The resulting mixture was stirred for 30 min and filtered. The filter cake was washed with water (20 mL) and dried in a vacuum oven at 45° C. to afford a 75% yield (215 mg) of 105e as an off-white solid: mp 203° C. dec; 1H NMR (500 MHz, CDCl3) δ 5.62 (s, 1H), 3.59 (t, 2H, J=7.0 Hz), 2.81 (t, 2H, J=6.0 Hz), 2.72 (t, 2H, J=7.0 Hz), 2.48 (t, 2H, J=6.0 Hz), 1.84 (m, 4H). MS (APCI+) m/z 208.3 (M+H)

Provenance & Evidence