Water → HCID 178491497, compound

Participants

Reaction Steps

A light brown solution of 3-(cyclopentylamino)-2-(2,4-dimethoxyphenyl)-1H-imidazo[1,2-b]pyrazole-7-carbonitrile (1.09 g, 3.1 mmol) in DMSO (200 mL) was stored for 35 days at RT. Within 24 h, it became a dark brown solution. After 35 days, LC/MS analysis indicated the absence of starting material and the presence of a strong desired peak. Then, it was poured into water (1 L) and the resulting cloudy brown solution was extracted with ethyl acetate (2×200 mL). Then, the combined extracts were washed with water and brine solution (2 L) to remove the DMSO. The organic layer was dried over anhydrous MgSO4, filtered, and concentrated to give the red brown paste (1.25 g) which was purified using an ISCO (150 g) column chromatography eluting with 0-40% ethyl acetate in hexanes. The desired fractions were combined and the solvent was removed under vacuum to obtain 224 mg (19.7% yield) of (E)-5-amino-1-(1-(cyclopentylimino)-2-(2,4-dimethoxyphenyl)-2-oxoethyl)-1H-pyrazole-4-carbonitrile as an off-white solid. 1H NMR (400 MHz, DMSO-d6) δ: 1.40-1.85 (br m, 8H), 3.66 (m, 1H), 3.66 (s, 3H), 3.87 (s, 3H), 6.62 (d, J=2.4 Hz, 1H), 6.71 (dd, J=2.4 and 9.0 Hz, 1H), 7.63 (s, 1H), 7.86 (d, J=9.0 Hz, 1H), 8.05 (brs, 2H). LC/MS calcd. for C19H21N5O3 (m/e) 367.4, obsd. 368.0 (M+H, ES+).

Provenance & Evidence