Three-component cyclocondensations. Two methods for the efficient preparation of 5-aminothiazolium salts via the reaction of isocyanides either with dimethylthioformamide and imino chloro sulfides or benzaldimines and aryl chlorothioformates
作者:Fabienne Berree、Yvelise Malvaut、Evelyne Marchand、Georges Morel
DOI:10.1021/jo00074a032
日期:1993.10
Treatment of imino chloro sulfides with dimethylthioformamide and isocyanides at room temperature provides selectively the 5-amino-4-(dimethylamino)-2-(methylthio)(or phenylthio)thiazolium salts. Similarly, the reactions of p-tolyl chlorothionoformate and phenyl chlorodithioformate with a mixture of benzaldimine and isocyanide afford rapidly the 5-amino-4-phenylthiazolium salts. We suggest that these reactions involve the N-(thiocarbonyl)formamidinium and benzylideniminium chlorides as transient intermediates, which are trapped by isocyanides according to a [1 + 4] cycloaddition process. The structure of the thiazolium salts and some of their reactivities are discussed.