Water → 7-Bromo-9-fluoro-1-methyl-4,5-dihydro-[1,2,4]triazolo[4,3-a]quinoline

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Reaction Steps

A suspension of 6-bromo-8-fluoro-3,4-dihydroquinoline-2(1H)-thione (1-4, 1.71 g, 6.57 mmol) and acetohydrazide (0.58 g, 7.89 mmol) in n-butanol (7 mL) was refluxed for 18 h under inert atmosphere. After cooling down to ambient temperature, ethyl acetate (10 mL) and water (10 mL) were added. The organic phase was then separated and the water phase was extracted with ethyl acetate (5×10 mL). The combined organic phases were washed with brine and dried over Na2SO4; the combined organic layers were then evaporated under reduced pressure to yield the crude product. The crude compound was purified by flash chromatography on silica gel to obtain the title compound as a white solid; 1H NMR (DMSO-D6, 500 MHz) δ=7.79 (dd, J=2.0 Hz, JHF=11.0 Hz, 1H), 7.63 (s, 1H), 2.95 (br s, 4H), 2.46 (d, JHF=8.5 Hz, 3H).

Provenance & Evidence