壳寡糖前驱体的制备与表征

研究了一种简单的用化学选择性来保护壳寡糖氨基的方法,用于制备N-邻苯二甲酰化壳寡糖,这种可溶性N-保护壳寡糖前驱体对壳寡糖进一步进行可控化学修饰非常重要.通过控制邻苯二甲酸酐与壳寡糖的摩尔比、反应时间及反应温度制备了取代度不同、产物组成均一的环状酰亚胺型邻苯二甲酰化壳寡糖前驱体,并用红外光谱法、X射线衍射对N-邻苯二甲酰化壳寡糖的取代度、分子结构等进行了表征.结果表明:随着邻苯二甲酸酐与壳寡糖氨基摩尔比的增加,产物的取代度增大,与有机溶剂的亲和性增加.XRD也表明,尽管壳寡糖链上悬挂很大的取代基,但N-邻苯二甲酰化壳寡糖却具有结晶性.     

Highly efficient procedure for the conjugate addition of amines to electron deficient alkenes catalyzed by novel ionic liquid

A highly efficient procedure has been developed for the conjugate addition of amines to electron deficient alkenes. The novel ionic liquid [HO₃S-bPy][FeCl₄] with both Lewis and Brønsted acid sites has been synthesized successfully for the reactions. The results show that the catalyst was very efficient for the conjugate addition of amines to electron deficient alkenes with excellent yields in several minutes. This method has several key features including operational simplicity, no need of any solvent, low cost of the catalyst used, high yields, reusability, excellent chemoselectivity, and wide applicability.