Dimethylformamide → 2-(3-Chloro-4-cyanophenyl)-3-cyclopentyl-2,3,3a,4-tetrahydrochromeno[4,3-c]pyrazole-7-carboxylic acid

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The title compound was prepared from methyl 3-(cyclopentylmethylene)-4-oxochroman-7-carboxylate, Preparation 31 (573 mg, 2.0 mmol) and 2-chloro-4-hydrazinylbenzonitrile hydrochloride; Preparation 1 (612 mg, 3.0 mmol) according to Method B and Method C. The crude precipitate was formed from dimethylformamide and methanol to give 2-(3-chloro-4-cyanophenyl)-3-cyclopentyl-2,3,3a,4-tetrahydrochromeno[4,3-c]pyrazole-7-carboxylic acid (yellow solid, 237 mg, 0.563 mmol, 28% yield). The title compound was largely present as (±)-(3RS,3aSR)-2-(3-chloro-4-cyanophenyl)-3-cyclopentyl-2,3,3a,4-tetrahydrochromeno[4,3-c]pyrazole-7-carboxylic acid. 1H NMR (400 MHz, DMSO-d6) δ ppm 13.20 (s, 1H), 7.98 (d, J=8.2 Hz, 1H), 7.70 (d, J=9.0 Hz, 1H), 7.58 (dd, J=8.2, 1.6 Hz, 1H), 7.47 (d, J=1.2 Hz, 1H), 7.41 (d, J=2.0 Hz, 1H), 7.20 (dd, J=8.8, 2.1 Hz, 1H), 4.95 (dd, J=9.4, 7.0 Hz, 1H), 4.78 (dd, J=10.2, 5.9 Hz, 1H), 4.31 (dd, J=13.3, 10.5 Hz, 1H), 4.00 (ddd, J=13.2, 9.7, 5.7 Hz, 1H), 2.03-2.16 (m, 1H), 1.13-1.68 (m, 8H). ES-MS m/z 422 (M+H).

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