Potassium Carbonate → 3-(2,5-Dichloropyrimidin-4-yl)pyrazolo[1,5-a]pyridine

Participants

Reaction Steps

K2CO3 (20.82 g, 150.65 mmol) and KOH (16.91 g, 301.31 mmol) were added in one portion to a mixture of (E)-4-(2-butoxyvinyl)-2,5-dichloropyrimidine (Intermediate 22, 74.46 g, 301.31 mmol) and 1-aminopyridinium iodide (66.9 g, 301.31 mmol) in DMSO (1.415 L) at r.t. The mixture was stirred at r.t. for 1.5 h and then at 90° C. for 4 h. After cooling, the mixture was diluted with water (5 L) and stirred for 0.5 h. The resulting solid was collected by filtration and washed with water (5 L). Purification by FCC, eluting with 0-20% EtOAc in CH2Cl2 gave the title compound (16.2 g, 20%) as a cream solid after trituration with diethyl ether; 1H NMR: 7.29 (1H, td), 7.74 (1H, ddd), 8.58 (1H, dt), 8.82 (1H, s), 8.98 (1H, dt), 9.10 (1H, s). m/z: ES+, MH+ 264.89.

Provenance & Evidence