Hydrochloric Acid → 3,4-dihydro-6-methoxy-2-[2-(p-toluenesulfonyloxy)ethyl]-2,5,7,8-tetramethyl-2H-benzopyran

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Reaction Conditions

Reaction Steps

Pyridine (150 ml) was added to 40 g (160 mmol) of 3,4-dihydro-2-(2-hydroxyethyl)-6-methoxy-2,5,7,8-tetramethyl-2H-benzopyran for dissolution of the latter. Then the solution was cooled to 0° C. and thereto was added with vigorous stirring 34.5 g of p-toluenesulfonyl chloride gradually. After stirring at 0° C. for 1 hour, the reaction mixture was poured into 1 liter of dilute hydrochloric acid and extracted with diethyl ether. The ether layer was washed with water, dried over anhydrous magnesium sulfate and filtered. After removal of low-boiling substances from the filtrate by distillation, the residue was purified by silica gel column chromatography to give 49.8 g (78.6% yield) of 3,4-dihydro-6-methoxy-2-[2-(p-toluenesulfonyloxy)ethyl]-2,5,7,8-tetramethyl-2H-benzopyran, which has the following FD mass spectrum.

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