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 (157-4, 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. Then the organic phase was separated, and the water phase was extracted with ethyl acetate (5×10 mL). The combined organic phases were washed with brine, dried over Na2SO4, and evaporated under reduced pressure. The crude compound was purified by flash chromatography on silica gel to obtain title compound (white solid). 1H NMR (DMSO-D6, 500 MHz) 6=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