我们在此提出了一种有效的加氢元素化反应方法,例如使用对甲苯基磺酰亚胺负载的双核钛配合物对杂枯烯碳二亚胺、芳基异氰酸酯和异硫氰酸酯与苯胺或苯硫酚进行氢胺化、氢硫醇化和氢磷酸化。所有反应均在温和的条件下和较短的反应时间内以优异的收率实现。通过光谱技术分离和充分表征产物。我们还提出了一种在第一步中涉及质子提取(苯胺或苯硫酚的 E-H)的机制。在反应机理中,双核 Ti IV配合物的酰胺基团充当离去基团,而磺酰亚胺键不受影响。
An “on-water” exploration of CuO nanoparticle catalysed synthesis of 2-aminobenzothiazoles
作者:Saroj Kumar Rout、Srimanta Guin、Jayashree Nath、Bhisma K. Patel
DOI:10.1039/c2gc35575b
日期:——
An âon-waterâ one-pot process has been engineered for the preparation of 2-aminobenzothiazole from ortho-halo (âF, âCl, âBr and âI) substituted unsymmetrical thioureas. For ortho âI and âBr substrates the reactions afford 2-aminobenzothiazoles under metal free condition promoted by base. However, the relatively inert ortho âCl and âF substrates undergo intramolecular arylthiolation only in the presence of CuO nanoparticles yielding 2-aminobenzothiazoles. This methodology provides easy access to aminobenzothiazoles utilising even the ortho âCl and âF substrates. The catalyst is recyclable several times without loss of substantial activity. Other remarkable features include the wide range of functional group tolerance, absence of chromatographic purification (for ortho âI and âBr substrates) and providing moderate to excellent yield of the products under mild conditions, thus rendering the methodology as a highly eco-friendly alternative to the existing methods.
The 1,10-phenanthroline-catalyzedtandemreaction of 2-iodoaniline with isothiocyanate in water is described, which provides an environmentally benign, efficient and simple route for the preparation of 2-aminobenzothiazoles. The present tandem process shows broad substrate scope in the absence of transition metals and phase-transfer catalysts.
A general, efficient, and more practical protocol for the base-mediated intermolecular or intramolecular S-arylation leading to the 2-aminobenzothiazole derivatives is reported. Remarkably, all reactions were carried out under transition-metal-free conditions with good to excellent yields, rendering the methodology presented herein highly valuable from both environmental and economic points of view
Metal-Free Synthesis of 2-Substituted (N, O, C) Benzothiazoles via an Intramolecular C−S Bond Formation
作者:Enguang Feng、He Huang、Yu Zhou、Deju Ye、Hualiang Jiang、Hong Liu
DOI:10.1021/cc9001839
日期:2010.7.12
convenient method was developed for the preparation of 2-substituted (N, O, C) benzothiazoles from N'-substituted-N-(2-halophenyl)thioureas, O'-substituted-N-(2-halophenyl) carbamothioates, or N-(2-halophenyl) thioamides via a base-promoted cyclization in dioxane without any transition metal. A one-pot variant combining the synthesis of the thiourea and the cyclization was also demonstrated. High yields
The impact of modular substitution on crystal packing: the tale of two ureas
作者:Vijay S. Koshti、Shridhar H. Thorat、Ravindra P. Gote、Samir H. Chikkali、Rajesh G. Gonnade
DOI:10.1039/c6ce01324d
日期:——
of iodide and urea/thiourea groups was synthesized in excellent yields in a single step synthetic protocol. The existence of the anticipated (thio)ureaderivatives was unambiguously established using a combination of 1–2D NMR spectroscopy, ESI-MS and single crystal X-ray diffraction studies. These (thio)urea compounds were classified into four classes as follows: a) mono-substituted urea, b) di-substituted