Yiming Ren, C. Cai
Feb 1, 2008
Citations
0
Influential Citations
21
Citations
Journal
Organic Preparations and Procedures International
Abstract
Benzimidazoles and imidazolines are very useful intermediates for the development of molecules of pharmaceutical or biological interest. Substituted benzimidazole derivatives have found applications in diverse therapeutic areas including antiulcers, antihypertensives, antivkals, antifungals, anticancers, and antihistaminics to name just a few.' In addition, imidazoline units are also used as synthetic intermediates, chiral auxiliaries, chiral catalysts and ligands for asymmetric cataly~is.~ Due to their wide range of pharmacological activity, industrial and synthetic applications, a number of methods have been reported for the synthesis of benzimidazoles and imidazolines, which include preparation from esters using aluminium organic reagents as the cataly~t,~" the reaction between N-ethoxycarbonylthioamides with 1,2-diamine~,"~ and the reaction of aldehydes with 1,2-diamines followed by N-halosuccinimides (X = C1, Br, I).3c Recently, several methods have been developed, where azalactone~,~" 2-aryl1,l -d ibr~moethanes ,~~ nitriles4" and amino a ~ n i d e s ~ ~ have been used as starting materials for this synthesis. However, many of the synthetic protocols suffer from disadvantages, such as requring anhydrous4" or harsh reaction condition^,^^ prolonged reaction times? use of metals and expensive reagents? etc. Recently, molecular iodine5 has received considerable attention as an inexpensive, nontoxic, readily available catalyst for various organic transformations to afford the corresponding