Cerium ammonium nitrate-catalyzed aerobic oxidative coupling of dithiocarbamates: facile synthesis of thioureas and bis(aminothiocarbonyl)disulfides
作者:Tian-Tian Li、Xiang-Hai Song、Mei-Shuang Wang、Ning Ma
DOI:10.1039/c4ra04628e
日期:——
Diverse disubstituted and trisubstituted thioureas were synthesized by the condensation of dithiocarbamate TEA (or DABCO) salts and amines using cerium ammonium nitrate (CAN) as a catalyst in high yields at room temperature. It is a one-pot method and it is unnecessary to isolate isothiocyanates. This reaction probably took place through nucleophilic addition of amines to isothiocyanates, which were generated by oxidative coupling of dithiocarbamates and the following decomposition of bis(aminothiocarbonyl)disulfides. When secondary amines and CS2 served as the reactants, bis(aminothiocarbonyl)disulfides were obtained via tandem nucleophilic addition/oxidative coupling reactions in moderate to excellent yields. In all the coupling reactions, the oxidant was air and CAN possibly acted as an SET catalyst.
A fluorous isatoic anhydride and isocyanate are synthesized and used as scavengers for amines in solution-phaseparallelsynthesis of urea, thiourea, and β-hydroxyamine analogs. The resulting fluorous derivatives are readily separated from the reaction mixture by solid-phase extractions (SPE) over FluoroFlash™ cartridges to give products with good purity. The SPE cartridges can be reused.