Tetrabutylammonium Iodide/t-Butylhydroperoxide Catalytic/Oxidative Synthesis of Thiazolylidene Derivatives

Abstract

A novel method based on reaction of β-ketothioamides (KTAs) with malononitrile to construct thiazolylidenes has been developed under metal-free conditions. This method used cheap tetrabutylammonium iodide (TBAI) as catalyst and t-butylhydroperoxide (TBHP) as oxidant in the presence of Et 3 N at room temperature for 1 h to synthesize a series of 4-aminothiazolylidene derivatives in good yields. This reaction has some advantages such as simple operation, mild reaction conditions, short reaction time, environmentally benign and simple work-up. Keywords thiazolylidenes; β-ketothioamides; TBAI/TBHP; catalysis 噻唑啉类化合物在生物和医药等领域都有重要应 用, 与许多生物酶或受体结合表现出多种生物活性 [1] . 例如, Pyochelin (I)不仅是微生物的铁载体而且具有抗肿 瘤活性 [2a] , Didehydromirabazole A (II)对实体瘤具有特 异选择性, 同时还具有广谱抗肿瘤活性 [2b] . 另外, 化合 物 III 可作为大麻素受体配体 [3] , 2-酰基亚甲基-3-甲基噻 唑啉(IV)具有潜在的治疗类风湿性关节炎和其他炎症的 作用 [4] (图 1). 目前该类化合物的合成方法研究较少 [5] , 因此建立新的简单、高效的噻唑啉衍生物合成方法具有 重要意义.