A solution of 1.0 g (2.3 mmol) of N-(6-benzyloxy-3-acetoxy-2,2-dimethylchroman-4-yl)-N-methyl-methanesulfonamide (Example 2) and 2.1 g (13.8 mmol) of DBU in 4.2 ml of toluene was heated at 105° C. for 5 h. The reaction mixture was diluted with EA and washed with hydrochloric acid until the aqueous phase gave an acidic reaction. The mixture was washed with sodium bicarbonate solution, dried over magnesium sulfate and concentrated i. vac., giving 0.85 g of N-(6-benzyloxy-2,2-dimethyl-2H-chromen-4-yl)-N-methyl-methanesulfonamide.
