Phosphorus oxychloride → 2-Chloropyrazolo[1,5-a]pyridine

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Reaction Steps

A stirred solution of pyrazolo[1,5-a]pyridin-2-ol (27-1; 0.9 g, 0.0067 mol) in POCl3 (10 mL) was heated in a sealed tube at 145° C. for 6 h. The reaction mixture was cooled to room temperature, poured into ice cold water (20 mL) and extracted with dichloromethane (3×20 mL). The combined organic layers were washed with saturated sodium chloride, dried over sodium sulphate and concentrated under vacuum to afford the crude compound, which was purified by column chromatography to obtain the title compound. 1H NMR (400 MHz, DMSO-d6) δ 8.36-8.34 (d, J=7.2 Hz, 1 H), 7.44-7.42 (d, J=9.2 Hz, 1 H), 7.17-7.13 (m, 1 H), 6.78-6.74 (m, 1 H), 6.43 (s, 1 H). MS (M+1): 152.8.

Provenance & Evidence