Potassium Iodide → 5-Benzyl-2-(4-fluorophenyl)-6,7-dihydropyrazolo[1,5-a]pyrazin-4(5H)-one

Participants

Reaction Conditions

Reaction Steps

To a solution of Intermediate 1C (80 g, 234 mmol) and potassium iodide (78 g, 469 mmol) in acetonitrile (800 mL) was added benzyl amine (28.2 mL, 258 mmol) and the reaction mixture was stirred at 90° C. for 12 h. Acetonitrile was removed under reduced pressure, crude was diluted with water and the aqueous layer was extracted with DCM (3×500 mL). The combined organic layer washed with brine, dried over Na2SO4, filtered and concentrated. The residue was purified by silica gel chromatography (120 g REDISEP® column, eluting with 1-2% methanol in chloroform). Collected fractions were concentrated together to afford Intermediate 1D (35 g, 46%). MS(ES): m/z=322 [M+H]+; 1H NMR (400 MHz, CDCl3) δ ppm 7.71-7.83 (m, 2H), 7.29-7.42 (m, 5H), 7.14 (s, 1H), 7.06-7.12 (m, 2H), 4.78 (s, 2H), 4.32-4.40 (m, 2H), 3.63-3.75 (m, 2H).

Provenance & Evidence