Aromatic ring transfer—a new synthesis of 2,4-diaryl-4H-3,1-benzothiazines
摘要:
A new synthetic approach to 2,4-diaryl-4H-3,1-benzothiazines is described based on the rearrangement of 2-isothiocyano triarylmethanes in the presence of AlCl3. An aryl ring is found to migrate to the carbon atom of an isothiocyano group followed by intramolecular cyclization as a result of electrophilic attack of the benzhydryl carbocation on the sulfur atom. (c) 2006 Elsevier Ltd. All rights reserved.
描述了1-(二芳基甲基)-2-异硫氰酸根合苯到2,4-二芳基-4 H -3,1-苯并噻嗪衍生物的新的重排。在Friedel-Crafts条件下用三氯化铝处理起始化合物导致芳基取代基通过亲电的ipso取代机理迁移,然后环化形成3,1-苯并噻嗪环。预期的分子内硫代氨基甲酰化反应也会发生,并且5,11-dihydro-6 H -dibenzo [ b,e分离出[]氮杂-5-硫酮副产物。讨论了影响反应机理和选择性的因素。还合成了相应的1-(芳基甲基)-2-异硫氰酸根合苯衍生物,并研究了它们在Friedel-Crafts反应条件下的行为,以证实中间体二苯甲基/苄基阳离子的稳定性在确定反应过程中的关键作用。 1-(二芳基甲基)-2-异硫氰酸根合苯-Friedel-Crafts-重排-芳基迁移-3,1-苯并噻嗪
Gram-Scale Synthesis of Substituted Triarylmethanes
作者:Meng-Yang Chang、Chun-Yi Lin、Shin-Mei Chen
DOI:10.1055/a-1863-3443
日期:2022.10
A high-yield, open-vessel route for the facile-operational, gram-scale synthesis of functionalized triarylmethanes (TRAMs) is described via silica-coated magnetic nanoparticles of modified polyphosphoric acid (NiFe2O4@SiO2-PPA)-mediated intermolecular Friedel–Crafts reaction of substituted aryl aldehydes with 2 equivalents of oxygenated arenes under environmentally friendly reaction conditions.