反应详情

Sulfuric acid (3.0 mL, 56 mmol) was added dropwise over 2 min to a solution of methyl 3-hydroxy-4-methoxybenzoate (3.64 g, 20 mmol), tetrabutylammonium hydrogensulfate (340 mg, 1.0 mmol), isopropyl nitrate (5.0 mL, 50 mmol), and dichloromethane (40 mL) at 0° C. The reaction was allowed to warm to rt, maintained for 45 min, and then quenched with ice water (100 mL). This mixture was extracted with dichloromethane (250 mL×2). The combined extracts were dried, filtered, concentrated, and purified by silica gel chromatography (4:1→3:7; hexanes:ethyl acetate) to give methyl 3-hydroxy-4-methoxy-2-nitrobenzoate: MS (ESI): 228.4.

1. temperaturemaintained for 45 min
2. customquenched with ice water (100 mL)
3. extractionThis mixture was extracted with dichloromethane (250 mL×2)
4. customThe combined extracts were dried
5. filtrationfiltered
6. concentrationconcentrated
7. custompurified by silica gel chromatography (4:1→3:7; hexanes:ethyl acetate)