tert-Butyl 2-(4-formylphenyl)morpholine-4-carboxylate (300 mg, 1.03 mmol) was dissolved in dimethylacetamide (4.5 ml). 1,2-Diaminobenzene (134 mg, 1.24 mmol) and sodium metabisulfite (294 mg, 1.54 mmol) were added and the reaction mixture was stirred at 90° C. overnight. After cooling, the reaction mixture was poured into water and extracted with ethyl acetate. The organic layer was dried over MgSO4 and evaporated. The crude material was purified by flash chromatography (20 g silica gel, 40 to 70% ethyl acetate in heptane) to yield a white solid (333 mg, 85%). MS (ISP): 280.3 (100%, [M-BOC+H]+), 380.2 (20%, [M+H]+).
