Acetic Acid → HCID 90011447, compound

Participants

Reaction Conditions

Reaction Steps

Step-1: Ethyl-1-(5-bromopyridin-2-yl)-5-methyl-1H-pyrazole-3-carboxylate: To a stirred solution of 5-bromo-2-hydrazinylpyridine (16.6 g, 89.0 mmol), in ethanol (5 mL) and acetic acid (10 mL) was added ethyl 2,4-dioxopentanoate (14.0 g, 89.0 mmol) drop-wise at 0° C. and the resulting mixture was stirred at 100° C. for 2 h. The reaction mixture was then cooled to room temperature and the solvent was evaporated under vacuum. The residue was diluted with water (50 mL) followed by ethyl acetate (100 mL). The layers were separated and the aqueous layer was extracted with ethyl acetate (2×100 mL). The combined organic layers were washed with brine (100 mL), dried (Na2SO4) and filtered. The filtrate was rotary evaporated and the crude product was purified by flash column chromatography (silica gel, ethyl acetate-hexanes system as eluent) to afford 2.60 g (10%) of the title compound as white solid. 1HNMR (400 MHz, CDCl3) δ 8.51-8.50 (m, 1H), 7.96-7.93 (m, 2H), 6.71 (s, 1H), 4.41 (q, J=7.0 Hz, 2H), 2.67 (s, 3H), 1.41 (t, J=7.0 Hz, 3H); ESI-MS (m/z) 310, 312 [(MH)+, Br79,81].

Provenance & Evidence