To a suspension of 2-(3-aminophenyl)-N-cyclopentyl-3-[2-(cyclopentylamino)-4-pyrimidinyl]pyrazolo[1,5-a]pyridin-7-amine (150, mg, 0.33 mmol) in N,N-dimethylformamide (5 mL) was added pyridine (40 μL, 0.49 mmol). The reaction mixture was cooled to 0° C. under nitrogen, then methanesulfonyl chloride (28 μL, 0.36 mmol) was added dropwise. After stirring at room temperature for 18 hours, the reaction mixture turned clear. Ethyl acetate and water were added and the phases separated. The organic phase was washed with water and brine, then dried over magnesium sulfate. Filtration and concentration, followed by flash chromatography (95:5 chloroform:methanol) gave N-(3-{7-(cyclopentylamino)-3-[2-(cyclopentylamino)-4-pyrimidinyl]pyrazolo[1,5-a]pyridin-2-yl}phenyl)methanesulfonamide (170 mg, 96%) as a yellow syrup. 1H NMR (CDCl3): δ 7.93 (d, 1H), 7.66 (d, 1H), 7.42 (m, 1H), 7.35–7.25 (m, 5H), 6.25 (m, 1H), 5.99 (m, 2H), 5.62 (broad, 1H), 4.29 (m, 1H), 3.96 (m, 1H), 2.94 (s, 3H), 2.10–1.99 (m, 4H), 1.77–1.49 (m, 12H). MS m/z 532 (M+1).
