反応 #47218

反応方程式

methyl 2-chloro-3,4-dihydroxybenzoate

KF

Dibromomethane

→

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

収率 42.0%

溶媒

DMF

water

反応条件

後処理

1. 1
   温度the mixture was heated to 120° C. for 4 h
2. 2
   温度The mixture was cooled down to room temperature
3. 3
   抽出extracted with ethyl ether
4. 4
   洗浄The combined ether layers were washed with 1M NaOH, water, brine
5. 5
   乾燥dried over anhydrous Na2SO4
6. 6
   ろ過filtered
7. 7
   その他solvent removed under vacuum
8. 8
   その他The crude product was absorbed onto silica
9. 9
   その他purified by flash column (silicagel, hexane

実験手順

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.

出典