To a solution of N-cyclopentyl-4-[2-(4-fluorophenyl)-7-(methylsulfanyl)pyrazolo[1,5-c]pyrimidin-3-yl]pyrimidin-2-amine (40 mg, 0.095 mmol) in dichloromethane (2 mL) was added 3-chloroperoxybenzoic acid (12 mg, 0.14 mmol) and the reaction mixture stirred at room temperature for 1 hour. t-Butylamine (3 mL) was added and heated to reflux for 3 hours. The reaction was allowed to cool and diluted with water. The mixture was extracted with ethyl acetate and the organic phase washed with brine before being concentrated under vacuum. The residue was purified by silica gel chromatography eluting with SO/5 acetone in dichloromethane to yield a 1:1 mixture of starting material and product. The residue was dissolved in dichloromethane (2 mL) and 3-chloroperoxybenzoic acid (18 mg, 0.21 mmol) was added. The mixture was stirred for 2 hours and then t-butylamine (3 mL) was added. The reaction mixture was stirred for 3 hours, diluted with water, extracted with ethyl acetate, washed with brine, concentrated, and the residue purified by silica gel chromatography eluting with 5% acetone in dichloromethane to yield N-(tert-butyl)-3-[2-(cyclopentylamino)pyrimidin-4-yl]-2-(4-fluorophenyl)pyrazolo[1,5-c]pyrimidin-7-amine (6 mg, 14%), 1H NMR (CDCl3): δ 8.02 (d, 1H), 7.72 (d, 1H), 7.60 (dd, 2H), 7.47 (d, 1H), 7.13 (t, 2H), 6.42 (s, 1H), 6.25 (d, 1H), 5.14 (bs, 1H), 4.28 (m, 1H), 2.04 (m, 2H), 1.45–1.78 (m, 15H). MS m/z 446 (M+1).
