m-Chloroperbenzoic acid → N-cyclopentyl-3-[2-(cyclopentylamino)pyrimidin-4-yl]-2-(4methoxyphenyl)pyrazolo[1,5-a]pyrimidin-7-amine

Participants

Reaction Conditions

Reaction Steps

N-Cyclopentyl-3-iodo-2-(4-methoxyphenyl)pyrazolo[1,5-α]pyrimidin-7-amine (63 mg, 0.15 mmol), dichlorobis(triphenylphosphine)palladium(II) (25 mg, 0.015 mmol), and 2-(methylsulfanyl)-4-(tributylstannyl)pyrimidine (78 mg, 0.19 mmol) were added to toluene (3 mL) and heated to 110° C. for 16 hours. Additional dichlorobis(triphenylphosphine)palladium(II) (6 mg) was added and the reaction heated to 110° C. for 24 hours. The reaction was allowed to cool to room temperature, diluted with ethyl acetate, poured into 10% aqueous potassium fluoride containing 1% methanol, and stirred for 20 minutes before being extracted with ethyl acetate. The organic phase was concentrated and the residue purified by silica chromatography, eluting with a gradient of 5% to 10% acetone in dichloromethane to yield 25 mg of an approximate 1:1 mixture of N-cyclopentyl-2-(4-methoxyphenyl)pyrazolo[1,5-α]pyrimidin-7-amine and N-cyclopentyl-2-(4-methoxyphenyl)-3-[2-(methylsulfanyl)pyrimidin-4yl]pyrazolo[1,5-α]pyrimidin-7-amine. To a 0° C. solution of this mixture in dichloromethane (1 mL) was added 3-chloroperoxybenzoic acid (0.099 mg, 0.058 mmol). The mixture was allowed to warm to room temperature and stirred for 2 hours. The mixture was diluted with dichloromethane, washed with saturated aqueous sodium bicarbonate, and concentrated. The residue was dissolved in cyclopentylamine and stirred at room temperature for 2.5 hours. The mixture was concentrated and the residue purified by silica chromatography, eluting with a gradient of 5% to 15% acetone in dichloromethane to yield 14 mg (11%) of N-cyclopentyl-3-[2-(cyclopentylamino)pyrimidin-4-yl]-2-(4methoxyphenyl)pyrazolo[1,5-α]pyrimidin-7-amine. 1H NMR (CDCl3):δ 8.37 (d, 1H), 8.26 (d, 1H), 7.67 (d, 2H), 6.99 (d, 2H), 6.50 (d, 1H), 6.11 (d, 1H), 5.01 (m, 1H), 4.09 (m, 1H), 3.90 (s, 3H), 2.20 (m, 2H), 1.75 (m, 14H); MS m/z 470 (M+1).

Provenance & Evidence