反应详情

To a heavy walled vial containing methyl 2-chloro-3,4-dihydroxybenzoate (899.8 mg, 4.4 mmol, 1 equiv.) in 13 mL DMF was added KF (1.29 g, 22.2 mmol, 5 equiv.) and the mixture was stirred at room temperature for 30 min. Dibromomethane (0.375 mL, 5.3 mmol, 1.2 equiv.) was added and the mixture was heated to 120° C. for 4 h. The mixture was cooled down to room temperature, diluted with water, and extracted with ethyl ether. The combined ether layers were washed with 1M NaOH, water, brine, dried over anhydrous Na2SO4, filtered and solvent removed under vacuum. The crude product was absorbed onto silica and purified by flash column (silicagel, hexane:ethyl acetate 8 Å to give 395.8 mg (42%) of methyl 4-chlorobenzo[d][1,3]dioxole-5-carboxylate as a colorless crystalline solid. See Tetrahedron Lett. 38: 3361-3364 (1978); U.S. Patent Appl. Publication No. 20050009867.

1. temperaturethe mixture was heated to 120° C. for 4 h
2. temperatureThe mixture was cooled down to room temperature
3. extractionextracted with ethyl ether
4. washThe combined ether layers were washed with 1M NaOH, water, brine
5. dry with materialdried over anhydrous Na2SO4
6. filtrationfiltered
7. customsolvent removed under vacuum
8. customThe crude product was absorbed onto silica
9. custompurified by flash column (silicagel, hexane