提出了前所未有的两步,一锅法合成苯并咪唑并二嗪5,5-二氧化物。当在热条件下仅形成稠合的苯并咪唑[1,2- b ] [1,2,4]噻二嗪时,已经达到了基于反应条件的区域选择性,而苯并咪唑[2,1- c ] [1,2,4]噻二嗪则在热条件下形成。仅在微波辐射下产生。该方案的显着特征包括2-氨基苯并咪唑与邻卤代磺酰氯的区域选择性磺酰化,随后形成NC键。这些稠合的区域异构体的酸形式已用于引入新型的含胍的异香豆素骨架。
提出了前所未有的两步,一锅法合成苯并咪唑并二嗪5,5-二氧化物。当在热条件下仅形成稠合的苯并咪唑[1,2- b ] [1,2,4]噻二嗪时,已经达到了基于反应条件的区域选择性,而苯并咪唑[2,1- c ] [1,2,4]噻二嗪则在热条件下形成。仅在微波辐射下产生。该方案的显着特征包括2-氨基苯并咪唑与邻卤代磺酰氯的区域选择性磺酰化,随后形成NC键。这些稠合的区域异构体的酸形式已用于引入新型的含胍的异香豆素骨架。
A Novel Mechanistic Study on Ultrasound-Assisted, One-Pot Synthesis of Functionalized Benzimidazo[2,1-<i>b</i>]quinazolin-1(1<i>H</i>)-ones
作者:Li-Hsun Chen、Tsai-Wen Chung、Bharat D. Narhe、Chung-Ming Sun
DOI:10.1021/acscombsci.5b00186
日期:2016.3.14
Ultrasound-assisted synthesis of benzimidazo[2,1-b]quinazolin-1(1H)-ones was achieved via piperidine-catalyzed three-component reaction of 2-aminobenzimidazoles, an aromatic aldehyde, and 1,3-dione in aqueous isopropanol. This mechanism was first suspected following our identification of unusual reaction intermediates in a one-pot reaction. An unprecedented coupling reaction, it involved a nucleophilic
通过哌啶催化的2-氨基苯并咪唑,芳香族醛和1,3-二酮在异丙醇水溶液中的三组分反应实现苯并咪唑并[2,1 - b ]喹唑啉-1(1 H)-的超声辅助合成。在我们确定了一锅反应中不寻常的反应中间体之后,首先怀疑了这种机制。前所未有的偶联反应,它涉及2-氨基苯并咪唑对原位生成的迈克尔加合物的亲核攻击,然后发生电环形成反应。与普遍接受的机理相反,2-氨基苯并咪唑与Knoevenagel加合物的直接反应不能释放目标化合物。
Three Component Divergent Reactions: Base-Controlled Amphiphilic Synthesis of Benzimidazole-Linked Thiazetidines and Fused Thiadiazines
作者:Manikandan Selvaraju、Sandip Dhole、Chung-Ming Sun
DOI:10.1021/acs.joc.6b01586
日期:2016.10.7
A divergent reaction of 2-aminobenzimidazole with isothiocyanates and dihalomethanes has been developed for the selective synthesis of benzoimidazothiazetidine and benzoimidazothiadiazine. A single-pot reaction of 2-aminobenzimidazole in the presence of sodium hydride delivers benzoimidazothiazetidine, whereas triethylamine promotes the formation of benzoimidazothiadiazine via a sequential stepwise, fashion. The reaction sequence involves the initial formation of thiourea followed by regioselective nucleophilic addition and intramolecular ring-closing with dihalo electrophiles. The observed regioselectivity,of this reaction is governed by the nature of bases and the reaction sequence.