Synthesis Of Polysubstituted Thiazoles And Polysubstituted Benzothiazines

Cyclic structures exist widely in many natural products and pharmaceuticals.Especially the heterocyclic compounds which display a wide range of decent bioactivity are applied in medicine,pesticide and biological chemistry.Therefore,it is very significant to develop new-type,efficient and environmental-friendly approaches for the synthesis of heterocyclic compounds.Enaminones have frequently been used as synthetic intermediates in organic chemistry due to their unique property.This thesis focuses on developing novel synthetic methodologies for heterocyclic compounds starting from ?-bromoenaminones or 2-Iodobenzamide compounds.This paper contains two main parts,Part one:firstly,a series of ?-bromoenaminones was synthesized.Then a novel procedure was developed for the synthesis of muti-substituted thiazole derivatives via cyclization in the presence of base.This system tolerated a broad range of a-bromoenaminones and achieved moderate to good yields of polysubstituted thiazole derivatives.Fifteen compounds were synthesized and one of which was characterized by X-ray single crystal diffraction.Part two:a new method was developed for the synthesis of muti-substituted benzothiazine derivatives catalyzed by copper salt.Fifteen compounds were synthesized in 48%?83%yields and one of which was characterized by X-ray single crystal diffraction.All new compounds in this paper were characterized by 1H NMR?13C NMR and HRMS spectroscopy.