Direct Intramolecular Amination Of Tryptophan Esters To Prepare Pyrrolo[2, 3-b] Indoles

Pyrrolo[2,3-b]indoles are widely used in chemical,pharmaceutical,the skeleton structure of the compounds are often found in molecular structure such as drugs,active natural products,etc.for example,Weidong Ding and others found a new kind of antibiotics,the pyrrolo[2,3-b]indole skeleton structure is an indispensable part;In addition,hydrogenated pyrrolo[2,3-b]indole skeleton structure,as a kind of important pharmacophore structure,also common in indole alkaloids and molecular structure of natural products.In short,the skeleton of pyrrolo[2,3-b]indole have wide scientific research value and market prospects.Traditional methods for the synthesis of pyrrolo[2,3-b]indoles,having many drawbacks.For example,there exists a multi-step synthesis,atom economy is not high,the conditions are harsh,the limited raw material sources,there needs the forerunner groups in substrate,applicability is not good,production rate is not high.Therefore,through a more simple starting materials,less reaction steps,mild reaction conditions,and the use of cheap pollution-free catalysts and oxidant to the preparation of pyrrolo[2,3-b]indoles is very necessary.Our goal is to find a more attractive approach to the pyrrolo[2,3-b]indole skeleton.This metal-free reaction has enabled the synthesis of pyrrolo[2,3-b]indoles from readily available tryptophan esters under mild conditions,and we can get a variety of derivatives by modifying in different positions.This method have many advantages,for example,the synthetic route is short,starting materials is simple,mild reaction conditions,inexpensive and pollution-free of peroxide,wide range of substrates,easy separation of product,and it has enabled the gramscale synthesis of pyrrolo[2,3-b]indoles.So this method will have good application prospect in the field of organic synthesis and medicine.