Dimethyl Sulfate → 4-methoxy-3-[3-[3-chloro-4-(trifluoromethoxy)phenyl]-1-oxo-2-propenyl]-2H-1-benzopyran-2-one

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Reaction Steps

In 15 ml of hexamethylphosphoramide was dissolved 1.37 g of 4-hydroxy-3-[3-[3-chloro-4-(trifluoromethoxy)phenyl]1-oxo-2-propenyl]-2H-1-benzopyran-2-one, to this solution was added 0.17 g of sodium hydride (60% oily), and this was stirred at room temperature for 30 minutes. Then, 0.8 ml of dimethyl sulfate, and this was stirred at 65° C. for 2 hours. 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 washed with t-butyl methyl ether to obtain 0.38 g of 4-methoxy-3-[3-[3-chloro-4-(trifluoromethoxy)phenyl]-1-oxo-2-propenyl]-2H-1-benzopyran-2-one [Compound No. (2c-17)] as a pale yellow crystal.

Provenance & Evidence