Hydrochloric Acid → 4-(2-Fluoro-4-nitrophenoxy)-5-methylpyrrolo[2,1-f][1,2,4]triazin-6-ol

Participants

Reaction Steps

To a heterogeneous mixture of 4-(2-fluoro-4-nitrophenoxy)-5-methylpyrrolo[2,1-f][1,2,4]-triazin-6-yl pivalate (1.45 g, 3.74 mmol) in absolute ethanol (19 mL), at room temperature under a nitrogen atmosphere, was added 1 N aqueous sodium hydroxide. The reaction mixture was stirred at ambient temperature for 1.5 h before being neutralized to pH 7 with 1 N aqueous hydrochloride. The reaction mixture was concentrated to remove ethanol, before being partitioned between ethyl acetate and water. The aqueous layer was extracted twice with ethyl acetate. The combined organic extracts were washed twice with water, once with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate and concentrated in vacuo. Purification by silica gel (Merck KGaA, 230–400 mesh particle size) flash chromatography, eluting with 2:1 hexane/ethyl acetate, afforded the title compound (602 mg, 53% for Steps A-B) as a yellow solid. 1H NMR (CDCl3) δ 8.20–8.12 (m, 2H), 7.84 (s, 1H), 7.58–7.53 (m, 1H), 7.53 (s, 1H), 4.76 (s, 1H), 2.48 (s, 3H); MS(ESI+) m/z 305.2 (M+H)+.

Provenance & Evidence