Facile synthesis of phthalidyl fused spiro thiohydantoins through silica sulfuric acid induced oxidative rearrangement of ninhydrin adducts of thioureas
作者:Subhro Mandal、Animesh Pramanik
DOI:10.1016/j.tet.2019.130817
日期:2020.1
A one-pot three-component sequential synthetic protocol produces structurally and biologically important phthalidyl fused spiro N,N′-disubstituted thiohydantoins from readily available aromatic isothiocyanates, primary amines and ninhydrin. In this three-step synthesis while the initial two steps are catalyst-free, in the final step silica sulfuric acid (SSA) induces an oxidative rearrangement in [3
一锅三组分顺序合成方案可生产结构和生物学上重要的邻苯二甲酰基稠螺N,N'易得的芳族异硫氰酸酯,伯胺和茚三酮制得的β-二取代硫代乙内酰脲。在此三步合成过程中,当最初的两个步骤均无催化剂时,在最后的步骤中,二氧化硅硫酸(SSA)在溶剂下茚三酮和硫脲的[3.3.0]-双环1,2-二醇加合物中引起氧化重排无条件生成最终产物螺旋融合的硫代乙内酰脲。SSA的适度酸度与适度的氧化性共同促进了1,2-二醇中间体中的轻度氧化重排,从而生产出具有多种功能的螺合硫代乙内酰脲。SSA的易于回收利用,产品的收率高至优异,基材范围更广,反应时间更短,三分之二的无溶剂工艺以及高原子经济性使该方法具有吸引力和实用性。