Cooperative Activating Effect of Tertiary Amine/DMSO on Elemental Sulfur: Direct Access to Thioaurones from 2′-Nitrochalcones under Mild Conditions
作者:Thanh Binh Nguyen、Pascal Retailleau
DOI:10.1021/acs.orglett.7b03547
日期:2018.1.5
A newmode for the activation of elemental sulfur is reported. In the presence of both DMSO and a tertiary aliphatic amine (triethylamine or N-methylpiperidine), this element reacts directly with a wide range of 2′-nitrochalcones 1 to provide the corresponding thioaurones 2 in high yields even at room temperature and in the absence of transitionmetal catalyst.
Abstract A new and efficient approach for the synthesis of thioflavones and thioaurones by competitive cascade cyclization of 2′-tosyloxychalcones has been developed. 2′-Tosyloxychalcones were smoothly converted into thioflavones and thioaurones by incorporation of sulfur atom using elementalsulfur and triethylamine in DMSO with good yields. The advantages of the methodology are the formation of both