Synthesis Of Tetrahydro-?-carbolines Via Metal-free Intramolecular Cyclization Of Allenamides And Propargyltryptamine

Alkaloids are a type of nitrogen-containing organic compounds that are widely found in nature and possess chemical properties similar to alkalis.Alkaloids have strong biological activity due to their own structure and are important effective ingredients in Chinese herbal medicine.At the same time,there are many kinds of alkaloids,diversified biological sources,and complex and diverse chemical structures,which have always attracted people's attention.Carboline alkaloids are an important branch of alkaloids.Due to their quantitative advantages and significant biological activity,they have become a hot spot for research and utilization at home and abroad.Carboline alkaloids occupies a crucial position in the research of alkaloids in terms of extraction and separation,biosynthesis,chemical synthesis,or biological activity.Part 1: NIS-induced intramolecular cyclization of tryptamine-diene to synthesize tetrahydro-?-carboline compoundsSince the iodine reagent is a kind of cheap,easy-to-obtain,environmentally friendly electrophile with the property of activating unsaturated bonds,a series of iodine-containing organic molecular modules can be synthesized by using this property.We have developed a method to synthesize tetrahydro-?-carboline compounds with tryptamine-diene as a substrate and inducing intramolecular cyclization of dienamine through a halogen reagent.Twenty-one tetrahydro-?-carboline derivatives were synthesized,and the expansion reaction was carried out,and two coupling products were obtained,which proved that the target compound has certain application potential.The obtained compounds were characterized by hydrogen nuclear magnetic resonance spectroscopy,carbon spectroscopy,infrared and high-resolution mass spectrometry.The reaction has the characteristics of mild reaction conditions,short reaction time and good substrate universality.Part 2: The study of the intramolecular cyclization of propargyl tryptamine to synthesize tetrahydro-?-carboline compounds by the combined action of alkali and silicaWe started from tryptamine,firstly modified its propargylation,and then synthesized multi-substituted tetrahydro-?-carboline derivatives by intramolecular ring closure under the action of a base,and synthesized 10 in a good yield.A tetrahydro-?-carboline derivative.The obtained compounds were characterized and confirmed by hydrogen nuclear magnetic resonance spectroscopy,carbon spectroscopy,infrared and high-resolution mass spectrometry.The method has the advantages of low-cost and easy-to-obtain reaction substrates,mild reaction conditions,high atom economy,etc.,and lays a solid foundation for subsequent studies on the biological activity of ?-carboline alkaloids.