Synthesis Of Imidazo[1,2-a]pyridine And Thiazole Derivatives From Amines

Nitrogen-containing heterocyclic compounds are very widely present and are used in various chemical fields.Imidazo[1,2-a]pyridines and thiazoles are a very important class of nitrogen heterocyclic compounds.Compounds with imidazo[1,2-a]pyridine as a backbone structure possess a variety of pharmacological activities and are common in various natural and synthetic drugs,such as zolpidem,which is mainly used for sedation and hypnosis in clinic.Thiazole ring is a kind of very important nitrogen-containing sulfur-containing five-membered heterocyclic ring.Its compounds have good application prospects in clinical medicinal,biological,materials science and other fields,and are mostly used in rubber accelerators and fungicides,chemical dyes,film color,etc.Therefore,it is of great significance to develop new and efficient synthetic methods for the construction of these two kinds of compounds.In this thesis,the method of synthesizing imidazo[1,2-a]pyridine and thiazole with amines as nitrogen source was studied.The main research contents are as follows:1.A study of synthesis imidazo[1,2-a]pyridine with easily available 2-aminopyridines and aldehydes as raw materials was carried out.The reaction was catalyzed by cheap elemental sulfur without transition metal catalysis.Under the optimized standard conditions,the reaction had good substrate applicability and functional group stability.Excellent yield can also be obtained by gram-scale reaction,which provides a new way for the synthesis of imidazo [1,2-a] pyridine.2.The reaction of three-component "one-pot" synthesis of 2,4-disubstituted thiazole compounds with benzylamine,elemental sulfur and acetophenone as raw materials was carried out.The reaction has excellent chemoselectivity.Under the promotion of inexpensive isonicotinic acid,the unactivated acetophenone and benzylamine are dehydrated condensed,terminally oxidized,and [2+2+1] cyclized highly selective synthesis 2,4-disubstituted thiazole compound.