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■ Synthesis of Trifluoromethylated Dihydro-1,4-oxathiin-3-carboxanilides through Polymer-bound Activated Ester

Hoh-Gyu Hahn,* Kee Hyuk Chang, Kee Dal Nam, Su Yeoul Bae, and Heduck Mah

*Organic Chemistry Laboratory, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 136-791, Korea

Abstract

A synthesis of new trifluoromethylated dihydro-1,4-oxathiin-3-carboxanilids (2) through polymer-bound activated ester is described. Chlorination of ethyl γ,γ,γ-trifluoroacetoacetate (3) followed by treatment of 2-mercaptoethanol gave hydroxyxathianes isomers (cis-10 and trans-11). Replacement of hydroxy to chlorine and then dehydrochlorination afforded trifluoromethyl dihydro-1,4-oxathiin ester (7). The polymer-bound trifluoromethylated dihydro-1,4-oxathiin-3-carboxylic acid, 4-hydroxy-3-nitrobenzophenone ester (16) was prepared through the reaction of polystyrene-bound 4-hydroxy-3-nitrobenzophenone (14) with the trifluoromethylated dihydro-1,4-oxathiin-3-carbonyl chloride (15). Refluxing of 16 with anilines in acetonitrile gave the corresponding carboxanilide (2). The reaction rate depended on the nucleophilicity of nitrogen in aniline.