Ethyl vinyl ether → HCID 57067109, compound

Participants

Reaction Steps

10 g of methyl (4aS, 7S, 7aR)-1, 4a, 5, 6, 7, 7a-hexahydro-1-hydroxy-7-methylcyclopenta[c]pyran-4-carboxylate obtained in Definite Example 4 was dissolved in 100 ml of dichloromethane, and after 50 ml of ethyl vinyl ether and then 100 mg of pyridinium paratoluenesulfonate were added while the reaction mixture was being cooled by ice. Then, the reaction mixture was stirred at room temperature for 24 hours. The reaction mixture solution was extracted with dichloromethane. After 200 ml of dichloromethane was added to the reaction mixture solution, the organic layer was washed with 50 ml of saturated sodium hydrogen carbonate solution and 50 ml of saturated sodium chloride solution, and was then dried by magnesium sulfate. After filtration, the solvent was distilled off under a reduced pressure. 2.5 g of the resulting yellow oily substance, i.e., methyl (1S, 4aS, 7S, 7aR)-1-[1-(ethoxy)ethoxy]-1, 4a, 5, 6, 7, 7a-hexahydro-7-methylcyclopenta[c]pyran-4-carboxylate was dissolved in 30 ml of anhydrous tetrahydrofuran without purification, and 26.5 ml of diisobutylaluminum hydride (1.0 mol THF solution) was added dropwise while the reaction mixture was being cooled by ice and being stirred (in an argon gas atmosphere). After the reaction mixture was stirred at the same temperature for 2 hours, 2 ml of acetone was added. Next, 3.4 ml of water, 3.4 ml of an aqueous sodium hydroxide and 10 ml of water were added in the order named, and the reaction mixture was stirred. When insoluble matters were precipitated, the precipitate was filtrated and the solvent was distilled off under a reduced pressure. 2.3 g of the resulting colorless oily substance, i.e., (1S, 4aS, 7S, 7aR)-1-[1-(ethoxy)ethoxy]-1, 4a, 5, 6, 7, 7 a-hexahydro-4-(hydroxymethyl)-7-methylcyclopenta[c]pyran was dissolved in 30 ml of anhydrous dichloro-methane without purification, and 4 ml of pyridine was added. Next, 4 ml of acetic anhydride was added dropwise, and after 50 mg of 4-dimethylaminopyridine was added, the reaction mixture was stirred at room temperature for 5 hours. The reaction mixture was extracted with 150 ml of ethyl acetate. The organic layer which was washed by 100 ml of water, 2N hydrochloric acid solution (100 ml×2), saturated sodium hydrogen carbonate solution (100 ml×2) and 100 ml of saturated sodium chloride solution was dried by anhydrous magnesium sulfate, and the solvent was distilled off under a reduced pressure. The resulting colorless oily substance was purified by column chromatography using 50 g of silica gel, and there was obtained 1.6 g of colorless oily substance (1S, 4aS, 7S, 7aR)-4-(acetoxymethyl)-1-[1-(ethoxy)ethoxy]-1, 4a, 5, 6, 7, 7a-hexahydro- 7-methylcyclopenta[c]pyran (yield=60%) from the hexane:ether=7:3 eluent.

Provenance & Evidence