Ethanol → Zaltoprofen

Participants

Reaction Steps

To a mixture of 150 mg of 2-(10,11-dihydro-10-oxodibenzo[b,f]-thiepin-2-yl)-propionamide and 2 ml of ethanol was added 400 mg of potassium hydroxide in 2 ml of water, and the mixture was refluxed with stirring for 6 hours. After the completion of the reaction, ethanol was removed by distillation to obtain a residue to which was added water. The residue was washed with ethyl acetate, and an alkaline layer was acidified with hydrochloric acid and extracted with ethyl acetate. The extract was washed with a saturated sodium chloride solution and dried over anhydrous sodium sulfate. The solvent was removed by distillation to obtain a brown oil substance, which was chromatographed over 4 g of silica gel and eluted with benzene-chloroform (1:1) to obtain a light yellow oil substance. This substance was recrystallized from benzene-n-hexane, thereby obtaining 96 mg (yield: 64%) of 2-(10,11-dihydro-10-oxodibenzo[b,f]thiepin-2-yl)-propionic acid as pale yellow crystals having a melting point of 130.5°-131.5° C.

Provenance & Evidence