5-Bromo-2-hydrazinopyridine → HCID 90011163, compound

Participants

Reaction Steps

Step-1: Ethyl 1-(5-bromopyridin-2-yl)-5-cyclopropyl-1H-pyrazole-3-carboxylate: To a stirred solution of ethyl 4-cyclopropyl-2,4-dioxobutanoate (0.378 g, 2.05 mmol) in acetic acid (5 mL) was added 5-bromo-2-hydrazinylpyridine (386 mg, 2.05 mmol) at room temperature and the resulting mixture was refluxed for 2 h. The reaction was then cooled to room temperature and the solvent was evaporated under vacuum. The crude product was purified by flash column chromatography (silica gel, ethyl acetate-hexane system as eluent) to afford 300 mg (43%) of the title compound as pale yellow syrup. 1HNMR (400 MHz, CDCl3) δ 8.55 (d, J=2.0 Hz, 1H), 7.98 (dd, J=2.0 & 8.0 Hz, 1H), 7.87 (d, J=8.0 Hz, 1H), 6.50 (s, 1H), 4.41 (q, J=7.0 Hz, 2H), 2.70-2.64 (m, 1H), 1.40 (t, J=7.0 Hz, 3H), 1.05-1.00 (m, 2H), 0.75-0.71 (m, 2H); ESI-MS (m/z) 336, 338 [(MH)+Br79,81].

Provenance & Evidence