Esterification and Chemoselective Synthesis of R-Tetrahydrothiazo-2- thione-4-carboxylic Esters Cata

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A series of esters of R-tetrahydrothiazo-2-thione-4-carboxylic acid[ R-TTCA] was synthesized by direct esterification of R-TTCA with alcohols(CH3OH, C2H5OH, n-C3H7OH, i-C3H7OH, n-C4H9OH, sec-C4H9OH) in the presence of TiCl4 as the catalyst at room temperature without using any other solvent or dehydrant in high yields,91.6%-99.1% for primary alcohols and 55%- 80% for secondary alcohols. The catalyst has a strong chemoselecfive activity for the esterification of primary alcohols with R-TTCA in the presence of secondary alcohols. Owing to high yield, high chemoselectivity, and mild conditions used, this is an efficient method for the esterification of primary alcohols with R-TTCA.
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