Example 2: Synthesis of 2-amino-1-(4-nitrophenyl)ethanone hydrochloride
2-Bromo-4'-nitroacetophenone (25 g) prepared in Example 1 was dissolved in dichloromethane (250 mL), hexamethylenetetramine (20.1 g) was added, and the reaction was stirred for 1 hour at room temperature. After the reaction was completed, the solid crude product (30 g) was collected by filtration. The crude product was dissolved in a mixture of ethanol (162 mL) and concentrated hydrochloric acid (40 mL) and the reaction was continued with stirring for about 3 hours. After the reaction mixture was left to stand for about 48 hours, the solid product was precipitated, filtered, washed with water and dried to give the target compound 2-amino-1-(4-nitrophenyl)ethanone hydrochloride (refer to the method described in US4812470).
Yield: 11.8 g (72% yield);
1H NMR (DMSO-d6, 300MHz): δ 8.3 (broad peak, 3H), 8.38 (double peak, 2H), 8.27 (double peak, 2H), 4.68 (single peak, 2H).