Reacción #47218

Ecuación de reacción

methyl 2-chloro-3,4-dihydroxybenzoate

KF

Dibromomethane

→

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

Rendimiento 42.0%

Disolventes

DMF

water

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturathe mixture was heated to 120° C. for 4 h
2. 2
   TemperaturaThe mixture was cooled down to room temperature
3. 3
   Extracciónextracted with ethyl ether
4. 4
   LavadoThe combined ether layers were washed with 1M NaOH, water, brine
5. 5
   Secadodried over anhydrous Na2SO4
6. 6
   Filtraciónfiltered
7. 7
   Otrosolvent removed under vacuum
8. 8
   OtroThe crude product was absorbed onto silica
9. 9
   Otropurified by flash column (silicagel, hexane

Procedimiento

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.

Fuente