Cyclopentylamine → 1-[7-(Cyclopentylamino)-2-(4-methoxyphenyl)pyrazolo[1,5-a]pyridin-3-yl]ethanone

Participants

Reaction Conditions

Reaction Steps

To a solution of 1-[7-(chloro)-2-(4-methoxyphenyl)pyrazolo[1,5-a]pyridin-3-yl]ethanone (5.0 g, 16.6 mmol) in toluene (100 mL) was added successively racemic-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (620 mg, 1.0 mmol), cesium carbonate (8.12 g, 24.9 mmol), cyclopentylamine (8.2 mL, 83.1 mmol), and palladium(II) acetate (150 mg, 0.66 mmol). The resulting mixture was stirred at 95° C. for 4 hours, at which time the reaction was judged complete by thin layer chromatography. The solution was cooled to room temperature and diethyl ether and water were added to the reaction mixture. The phases were separated, and the aqueous phase again extracted with diethyl ether. The combined organic phases were dried (magnesium sulfate), filtered and concentrated. The resulting residue was purified by flash chromatography (4:1 hexanes:ethyl acetate) to give 1-[7-(cyclopentylamino)-2-(4-methoxyphenyl)pyrazolo[1,5-a]pyridin-3-yl]ethanone (5.66 g, 97%) as a yellow foam. 1H NMR (CDCl3): δ 7.65 (d, 1H), 7.48 (d, 2H), 7.39 (t, 1H), 6.99 (d, 2H), 6.09 (d, 1H), 6.01 (d, 1H), 3.95 (m, 1H), 3.84 (s, 3H), 2.09 (s, 3H), 2.09-2.00 (m, 2H) 1.76-1.22 (m, 6H); MS m/z 350 (M+1).

Provenance & Evidence