反应详情

10 g of 5-hydroxy-8-benzyloxy-3,4-dihydrocarbostyril was dissolved in 100 ml of anhydrous tetrahydrofuran, and 100 mg of p-toluenesulfonic acid was added to the solution. 10 g of dihydropyran was slowly added dropwise thereto at room temperature while stirring. After completion of the addition, the mixture was stirred at room temperature for 12 hours, poured into a large volume of a saturated aqueous solution of sodium chloride and then extracted with chloroform. The extract was washed successively with a 5% aqueous solution of sodium hydroxide and water, and the chloroform layer dried over anhydrous potassium carbonate. The chloroform was evaporated under reduced pressure, and the residue was crystallized from petroleum ether. Recrystallization from ethanol-water afforded 9.5 g of 8-benzyloxy-3,4-dihydrocarbostyril-5-ol-tetrahydropyranyl ether (IV) as colorless needle-like crystals having a melting point of 113.5°-114° C.

1. additionAfter completion of the addition
2. stirringthe mixture was stirred at room temperature for 12 hours
3. extractionextracted with chloroform
4. washThe extract was washed successively with a 5% aqueous solution of sodium hydroxide and water
5. dry with materialthe chloroform layer dried over anhydrous potassium carbonate
6. customThe chloroform was evaporated under reduced pressure
7. customthe residue was crystallized from petroleum ether
8. customRecrystallization from ethanol-water