反应详情

To a suspension of 2-(1H-indol-3-yl)-5,5-dimethylcyclohexane-1,3-dione of Example 1f (2.5 g, 9.8 mmol) in diethoxymethoxyethane (20 mL), tetrafluoroboric acid (54 wt % solution in diethyl ether, 2 mL, 14.5 mmol) was added in two portions under stirring. The mixture was stirred at room temperature for 2 h and diluted with diethyl ether (20 mL). The solid product was filtered off, washed with diethyl ether and air-dried at room temperature to give 2.4 g (70%) of the product as red crystals, which was used in the next step without purification.

1. additionwas added in two portions
2. stirringThe mixture was stirred at room temperature for 2 h
3. filtrationThe solid product was filtered off
4. washwashed with diethyl ether
5. customair-dried at room temperature