反应详情

Methyl 7,8-dimethoxy-2H-1-benzopyran-5-carboxylate (390 g, 1.56 mol) in toluene (1.6 L) was cooled to -15° and a solution of sodium bis(2-methoxyethoxy)aluminum hydride (908 mL, 3.5M in toluene, 3.18 mol) and morpholine (277 g, 3.18 mol) in toluene (900 mL) was added over a 45 min period. After stirring for an additional 30 min, 2N sodium hydroxide solution (2.85 L) was added. The organic layer was separated, washed with 0.8N hydrochloric acid (3×1 L), 5% sodium bicarbonate (500 mL) and water (1 L), dried (MgSO4) and concentrated to give 7,8-Dimethoxy-5-formyl-2H-1-benzopyran (344 g, 86%).

1. customThe organic layer was separated
2. washwashed with 0.8N hydrochloric acid (3×1 L), 5% sodium bicarbonate (500 mL) and water (1 L)
3. dry with materialdried (MgSO4)
4. concentrationconcentrated