Реакция #47218

Уравнение реакции

methyl 2-chloro-3,4-dihydroxybenzoate

KF

Dibromomethane

→

methyl 4-chlorobenzo[d][1,3]dioxole-5-carboxylate

Выход 42.0%

Растворители

DMF

water

Условия реакции

Обработка

1. 1
   Температураthe mixture was heated to 120° C. for 4 h
2. 2
   ТемператураThe mixture was cooled down to room temperature
3. 3
   Экстракцияextracted with ethyl ether
4. 4
   ПромывкаThe combined ether layers were washed with 1M NaOH, water, brine
5. 5
   Сушкаdried over anhydrous Na2SO4
6. 6
   Фильтрацияfiltered
7. 7
   Другоеsolvent removed under vacuum
8. 8
   ДругоеThe crude product was absorbed onto silica
9. 9
   Другоеpurified by flash column (silicagel, hexane

Методика

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.

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