Triethylamine → 7-Chloro-2-(2-chlorophenyl)-pyrazolo[1,5-a]pyrimidine

Participants

Reaction Conditions

Reaction Steps

To a slurry of 2-(2-chlorophenyl)-4H-pyrazolo[1,5-a]pyrimidin-7-one (I-1A-1b; 30.0 g, 122 mmol) and triethylamine (25.5 ml, 183 mmol) in toluene (1.3 liters) at room temperature was added POCl3 (58 ml, 0.62 mol), dropwise. The mixture was heated at 95° C. for 4 hours, cooled to room temperature, then slowly added to a stirred mixture of ice, sodium bicarbonate (300 g) and ethyl acetate (1 liter), keeping the temperature at 0° C. The aqueous layer was separated and extracted with additional ethyl acetate. The combined organic layers were dried (MgSO4), and then concentrated, in vacuo, to afford an amber solid. This material was purified by silica gel chromatography using 2:1:0.1 methylene chloride/hexanes/methanol as eluant to afford I-1A-1c as a colorless solid (17.5 g, 54%): +APcI MS (M+1) 264.2; 1H NMR (400 MHz, CD2Cl2) δ 8.40 (d, J=4.6 Hz, 1H), 8.00–7.97 (m, 1H), 7.56–7.53 (m, 1H), 7.45–7.39 (m, 2H), 7.34 (s, 1), 7.03 (d, J=4.6 Hz, 1H).

Provenance & Evidence