Dimethyl Sulfate → 4-methoxy-3-[3-[3-chloro-4-(trifluoromethoxy)phenyl]-1-oxo-2-propenyl]-6-methyl-2H-pyran

Beteiligte Stoffe

Reaktionsschritte

In 4 ml of hexamethylphosphoramide was dissolved 0.33 g of 4-hydroxy-3-[3-[3-chloro-4-(trifluoromethoxy)phenyl]-1-oxo-2-propenyl]-6-methyl-2H-pyran-2-one, to this solution was added 50 mg of sodium hydride (60% oily), and the mixture was stirred at room temperature for 30 minutes. Then, 0.2 ml of dimethyl sulfate was added, and the mixture was stirred at 65° C. for 1 hour, and at room temperature overnight. Thereafter, the reaction mixture was added to ice water, and this was extracted with ethyl acetate. The organic layer was washed with an aqueous saturated sodium chloride solution, dried with anhydrous magnesium sulfate, and concentrated. The residue was subjected to silica gel column chromatography to obtain 0.13 g of 4-methoxy-3-[3-[3-chloro-4-(trifluoromethoxy)phenyl]-1-oxo-2-propenyl]-6-methyl-2H-pyran [Compound No. (2a-17)] as a pale yellow crystal.

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