p-Toluenesulfonic acid → HCID 9884605, compound

Participants

Reaction Steps

A few mg of toluene-4-sulfonic acid are added to a solution of 7 g of 3-[1-(4-fluorophenyl)-1-hydroxy-1-(4-methanesulfonylphenyl)methyl]dihydrofuran-2-one, prepared in Example 3, in 100 ml of toluene and the mixture is refluxed for 10 hours in a Dean-Stark apparatus. The solvent is then evaporated off to dryness under vacuum and the residue is chromatographed using a 9/1 dichloromethane/acetone mixture as the eluent to give an oil, which is chromatographed using t-butyl methyl ether as the eluent to give 2.9 g of (E)-3-[1-(4-fluorophenyl)-1-(4-methanesulfonylphenyl)methylidene]dihydrofuran-2-one (second product eluted) in the form of crystals melting at 187°-9° C. 1.5 g of (Z)-3-[1-(4-fluorophenyl)-1-(4-methanesulfonylphenyl)methylidene]dihydrofuran-2-one (first product eluted) are recovered in the form of crystals melting at 157°-158° C.

Provenance & Evidence