2-Methoxyethanol → HCID 90011233, compound

Participants

Reaction Steps

Step-3: Ethyl 1-(5-Bromopyridin-2-yl)-3-cyclopropyl-1H-pyrazole-5-carboxylate: To a stirred solution of ethyl 4-cyclopropyl-2-(methoxyimino)-4-oxobutanoate (420 mg, 1.97 mmol) in acetic acid:2-methoxyethanol (6 mL, 2:1) was added 5-bromo-2-hydrazinylpyridine (370 mg, 1.97 mmol) at room temperature. The resulting mixture was refluxed for 3 h. The reaction mixture was cooled to room temperature and the solvent was evaporated under vacuum. The crude product was purified by flash column chromatography (silica gel, ethyl acetate-hexanes system) to afford 220 mg (33%) of the title compound as pale yellow syrup. 1HNMR (400 MHz, CDCl3) δ 8.49 (d, J=2.0 Hz, 1H), 7.95 (dd, J=2.0 & 8.0 Hz, 1H), 7.58 (d, J=8.0 Hz, 1H), 6.56 (s, 1H), 4.30 (q, J=7.0 Hz, 2H), 2.04-1.98 (m, 1H), 1.29 (t, J=7.0 Hz, 3H), 1.02-0.97 (m, 2H), 0.83-0.79 (m, 2H); ESI-MS (m/z) 336, 338 [(MH)+, Br79,81].

Provenance & Evidence