反应 #2139955

反应方程式

3-benzyloxy-8-ethoxy-4,7-difluoro-6H-benzo[c]chromen-6-one

compound

4-bromo-1-ethoxy-2-fluorobenzene

ethylene glycol dimethyl ether

sodium borohydride

→

3-benzyloxy-8-ethoxy-4,7-difluoro-6H-benzo[c]chromene

收率 78.0%

溶剂

THF

反应条件

后处理

1. 1
   workup.ADDITION2.37 ml (23.0 mmol) of boron trifluoride/THF complex were added with ice-
2. 2
   温度cooling
3. 3
   其他The mixture was subjected to conventional purification

实验过程

2.00 g (5.24 mmol) of 3-benzyloxy-8-ethoxy-4,7-difluoro-6H-benzo[c]chromen-6-one, the compound of Example 841, were dissolved in 12 ml of THF, and 2.37 ml (23.0 mmol) of boron trifluoride/THF complex were added with ice-cooling. 24 ml of ethylene glycol dimethyl ether and then in portions 530 mg of sodium borohydride were subsequently added. The mixture was subsequently stirred at room temperature for 18 hours and then transferred onto ice. The mixture was subjected to conventional purification, giving 1.5 g (78% of theory) of 3-benzyloxy-8-ethoxy-4,7-difluoro-6H-benzo[c]chromene as colourless crystals. These were dissolved in THF, hydrogenated at a pressure of 1 bar in the presence of 0.6 g of Pd/C (5%), filtered and evaporated, giving 1.2 g (99% of theory) of 8-ethoxy-4,7-difluoro-3-hydroxy-6H-benzo[c]chromene as colourless crystals.

来源