Phosphorus oxychloride → 7-Chloro-3-(4-chlorophenyl)-2-(2-chlorophenyl)-5-methylpyrazolo[1,5-a]pyrimidine

Participants

Reaction Conditions

Reaction Steps

To a slurry of 3-(4-chlorophenyl)-2-(2-chlorophenyl)-5-methylpyrazolo[1,5-a]pyrimidin-7-ol (I-3A-4a; 1.08 g, 2.92 mmol) and diisopropylethylamine (0.763 ml, 4.38 mmol) in toluene (30 ml) at room temperature was added POCl3 (1.36 ml, 14.6 mmol), dropwise. The mixture was heated at 100° C. for 16 hours, cooled to room temperature, then slowly added to a stirred mixture of ice, saturated aqueous sodium bicarbonate and ethyl acetate. The aqueous layer was separated and extracted with additional ethyl acetate. The combined organic layers were washed with brine, dried (MgSO4), and then concentrated, in vacuo, to afford the crude product. Purification on a Biotage™ Flash 40M column using 0–10% ethyl acetate in hexanes as eluant afforded I-3A-4b (1.05 g, 92%) as a yellow solid: +ESI MS (M+1) 388.1; 1H NMR (400 MHz, CD2Cl2) δ 7.55–7.35 (m, 6H), 7.26 (d, J=8.7 Hz, 2H), 6.98 (s, 1H), 2.64 (s, 3H).

Provenance & Evidence