Phosphorus oxychloride → 7-Chlorothieno[3,2-b]pyridine

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Reaction Conditions

Reaction Steps

A stirred suspension of thieno[3,2-b]pyridin-7-ol (5.0 g, 33.1 mmol) in POCl3 (15 mL) was heated at 105° C. in an oil bath for 4 hrs. The resultant solution was cooled to room temperature and the POCl3 was removed under reduced pressure. The residue was cooled in an ice/water bath and cold water was added. The mixture was made basic with concentrated NH4OH solution and extracted with EtOAc. The organic extract was dried over anhydrous sodium sulfate and concentrated to produce oil, which was purified by column chromatography (eluent EtOAc-hexane, 1:4) to afford the title compound as a brown solid (4.5 g, 72% yield). 1H NMR (400 MHz, CDCl3) δ (ppm): 8.60 (d, J=4.9 Hz, 1H), 7.80 (d, J=5.5 Hz, 1H), 7.60 (d, J=5.5 Hz, 1H), 7.30 (d, J=4.9 Hz, 1H).

Provenance & Evidence