反应详情

A mixture of 10 g of rac-2-methoxy-3,4-dihydro-2,5,7,8-tetramethyl-6-(phenylmethoxy)-2H-1-benzopyran, 10 g of calcium chloride, 100 ml of hexane and 50 ml of diethyl ether was stirred at -5° to -10° C. while HCl gas was bubbled in for 1 hr. An additional 10 g of calcium chloride was added and stirring was continued at room temperature for 2 hr. The mixture was filtered and the filtrate was concentrated in vacuo giving 10.2 g of title product as a light-brown oil. Proton NMR analysis revealed that this product consisted of 66% of the title compound and 33% of the starting 2-methoxy chroman.

1. customwas bubbled in for 1 hr
2. additionAn additional 10 g of calcium chloride was added
3. filtrationThe mixture was filtered
4. concentrationthe filtrate was concentrated in vacuo