反应详情

As shown by scheme (CLX), to a solution of 2-amino-3-nitrophenol 44 (10 g, 65 mmol) in anhydrous 1,4-dioxane (1 L) was added bromine (12.5 g, 78 mmol). The mixture was stirred at room temperature overnight. The solid was collected by filtration, washed with dioxane and dried. 2-amino-5-bromo-3-nitrophenol 45 (18 g, 90%) was obtained as its HBr salt in a form of a yellow solid. 1H NMR (DMSO-d6): δ 6.28 (br, 2H); 6.99 (d, J=2.2 Hz, 1H); 7.57 (d, J=2.1 Hz, 1H). MS (ESI+): m/z=234. Compound 45 (6 g, 19.1 mmol) was converted into compound 46 by using a method that was analogous to that used to synthesize compound 27, as shown on scheme (CXLI). Hydrogenation of compound 46 affords compound 47 (3.1 g, 67%) as a red solid.

1. filtrationThe solid was collected by filtration
2. washwashed with dioxane
3. customdried