Hydrochloric Acid → 3-(2-Bromopyridin-3-yl)-2H-1,4-benzoxazin-5-amine

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Reaction Conditions

Reaction Steps

A suspension of iron (1.71 g, 30.7 mmol) (<10 micron) in ethanol (33.5 mL) was treated with 1.0 M hydrogen chloride in water (3.1 mL, 3.1 mmol) and was stirred at 60° C. for 2 h. The mixture was then cooled to 55-60° C. and treated with 5.0 M ammonium chloride in water (5.3 mL, 26.4 mmol) followed by addition of 3-(2-bromopyridin-3-yl)-5-nitro-3,4-dihydro-2H-1,4-benzoxazin-3-ol (2.16 g, 6.13 mmol, washed with 5 mL ethanol). The resulting suspension was stirred at 60-65° C. for 2 h. The suspension was diluted with acetonitrile to about 100 mL and filtered over Celite. The solid was washed with additional acetonitrile and the filtrate was concentrated to a solid. This solid was dissolved in ethyl acetate which was then dried over magnesium sulfate, filtered, and concentrated to give the desired product (1.85 g, 99%), used without further purification. LCMS calculated for C13H11BrN3O (M+H)+: m/z=304.0, 306.0. found: 304.0, 306.0.

Provenance & Evidence