The Research Of Ring-opening Reactions Of Aziridines With Nucleophile

Aziridine is a kind of saturated ternary heterocyclic compounds which has biological activity, exists in some bioactive natural product, has the antivirus, antitumor, and other biological activity. The ring-opening reaction of aziridines with sulfur nucleophilic reagent can be used for the synthesis ofβ-amino sulfides which are important for the synthesis of many biologically interesting molecules such as amino acids, heterocycles and alkaloids.The simple and most straightforward route toβ-amino sulfides involves the regioselective ring opening of tosylaziridines with thiols using acid or base catalysts. Lewis acids such as boron trifluoride etherate and zinc chloride as well as Br(?)nsted acids-like trifluoromethanesulfonic acid have been employed as acid catalysts. However, many of these methods suffer from the fact that a Lewis acid or strong base was necessary to effect the reaction. Moreover, varied reaction conditions are needed for various aziridines because of the different reactivity of substrates and reagents, as well as the complexity of the structure of aziridines.This paper focuses on developing a new simple, easy to operate, economic, and environmental friendly nucleophilic ring-opening reaction method. Through changing the conditions of the reaction, and screening different catalysts, in order to improve the reaction yield and regio-and stereoselective, we found a), Under solvent-free conditions, silica gel promoted the ring-opening of aziridines with various nucleophiles (such as 4-bromo thiophenol, thioacetic acid, sodium thiocyanate, etc) to give the correspondingβ-aminosulfides, respectively. Most reactions gave high yields up to 99% within 2 h. b), Cheap and easily available organic base TMG catalyzed the ring-opening of aziridines with various nucleophiles (such as 4-bromo thiophenol, thioacetic acid, etc) in toluene with high yield and high regioselectivity, affording the correspondingβ-aminosulfides, respectively. Most reactions completed within one day with high up to 97% yield. When the catalyst loading was decreased to 1%, the reaction could still give 70% yield in 30 h.