N-Chlorosuccinimide/Sodium Hydroxide-Mediated Synthesis of Benzimidazoles from Amidines under Mild Conditions
摘要:
A convenient room-temperature one-pot procedure for the preparation of benzimidazoles derivatives from N-arylamidines has been developed. The reaction of N-aryl-N'-chloro amidines, generated by the treatment of N-arylamidines with N-chlorosuccinimide, in presence of sodium hydroxide provides benzimidazoles in good to excellent yields. Nitrogen anion generated in situ from succinimide (by-product of the chlorination step using NCS) and hydroxide anion was found to be highly effective as Bronsted base to promote the cyclization into benzimidazole of N-aryl-N'-chloroamidine.
Iron(II) Bromide-Catalyzed Synthesis of Benzimidazoles from Aryl Azides
作者:Meihua Shen、Tom G. Driver
DOI:10.1021/ol801227f
日期:2008.8.7
The identity of the ortho-substituent of an arylazide influences its reactivity toward transition metals. Substitution of a vinyl group with an imine disables rhodium(II)-mediated C-H amination and triggers a Lewis acid mechanism catalyzed by iron(II) bromide to facilitate benzimidazole formation.
An intramolecular aryl C−H amination reaction has been achieved using molecular iodine as the sole oxidant for the synthesis of benzimidazole derivatives. The required substrates were readily prepared by addition or coupling of arylamines with the corresponding nitriles or aryl iodides. Iodine‐mediated oxidative cyclization of these substrates in the presence of potassium carbonate (K2CO3) as base
使用分子碘作为合成苯并咪唑衍生物的唯一氧化剂,已经实现了分子内芳基CH氨基化反应。通过将芳基胺与相应的腈或芳基碘加成或偶联,可以轻松制备所需的底物。在以碳酸钾(K 2 CO 3)为碱的情况下,这些底物的碘介导的氧化环化作用可提供中等至良好收率的相应产物。此处介绍的无过渡金属协议对空气不敏感,操作简单。这种通用且环保的合成方法学广泛适用于各种N芳基取代的am和吡啶2胺,可直接接触1 H来自相应前体的-苯并[ d ]咪唑和吡啶并[1,2- a ]苯并咪唑衍生物。
Water-soluble preflux, printed circuit board, and process for treating the surface of a metal in a printed circuit board
申请人:——
公开号:US20030141351A1
公开(公告)日:2003-07-31
The invention provides a water-soluble prefluxe that can solve problems with a soldering land array having a narrow spacing in that fused solder is likely to cause soldering bridges with defective soldering, a printed circuit board with its film formed thereon, and a surface treatment process for a metal in that circuit. The water-soluble preflus comprises given two different benzimidazoles compound and an iodine-based compound optionally with an amino acid, etc. The invention provides a printed circuit board with a film of that preflux formed thereon, and a surface treatment process for the metal in that circuit.