Synthesis of trifluoromethylated dihydro-1,4-oxathin-3-carboxanilides through polymer-bound activated ester

A synthesis of new trifluoromethylated dihydro-1,4-oxathiin-3-carboxanilids (2) through polymer-bound activated ester is described. Chlorination of et hyl gamma,gamma,gamma-trifluoroacetoacetate (3) followed by treatment of 2- mercaptoethanol gave hydroxyoxathianes isomers (cis-10 and trans-11). Repla cement of hydroxy to chlorine and then dehydrochlorination afforded trifluo romethyl dihydro-1,4-oxathiin ester (7). The polymer-bound trifluoromethyla ted dihydro-1,4-oxathiin-3-carboxylic acid, 4-hydroxy-3-nitrobenzophenone e ster (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 gav e the corresponding carboxanilide (2). The reaction rate depended on the nu celophilicity of nitrogen in aniline.