Water → N-cyclopentyl-3-[2-(cyclopentylamino)-4-pyrimidinyl]-2-(4-methoxyphenyl)-pyrazolo[1,5-a]pyridin-7-amine

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Reaction Steps

To a solution of (2E)-1-[7-(cyclopentylamino)-2-(4-methoxyphenyl)pyrazolo[1,5-a]pyridin-3-yl]-3-(dimethylamino)-2-propen-1-one (5.97 g, 14.7 mmol) in dimethylformamide (80 mL) was added N-cyclopentyl guanidine hydrochloride (4.33 g, 26.5 mmol; Prepared by modification of a procedure from Bannard, R. A. B. et al., Can. J. Chem. 1958, 36, 1541–1549), followed by potassium carbonate (2.03 g, 14.7 mmol). The resulting solution was heated at reflux for 6 hours. Upon cooling to room temperature, water was added. The mixture was extracted with ethyl acetate. The ethyl acetate phase was washed with brine, dried (magnesium sulfate), filtered and concentrated in vacuo. The resulting residue was purified by flash chromatography (4:6 ethyl acetate:hexane) to give N-cyclopentyl-3-[2-(cyclopentylamino)-4-pyrimidinyl]-2-(4-methoxyphenyl)-pyrazolo[1,5-a]pyridin-7-amine (5.02 g, 73%) as a yellow solid. 1H NMR (CDCl3): δ 7.95 (d, 1H), 7.72 (d, 1H), 7.54 (dd, 2H), 7.25 (t, 1H), 6.94 (dd, 2H), 6.28 (d, 1H), 6.00–5.97 (m, 2H), 5.03 (d, 1H), 4.33–4.31 (m, 1H), 3.96 (m, 1H), 3.83 (s, 3H), 2.10–2.01 (m, 4H), 1.77–1.50 (m, 12H); MS m/z 469 (M+1); Anal. Calcd for C28H32N6O: C, 71.77; H, 6.88; N17.93. Found: C, 71.41; H, 7.02; N, 17.89.

Provenance & Evidence