Study On The Chemical Selective Diversity Of The Bromocyclization

Through bromocyclization to construct multi functionalized cyclic compounds is one of the most important tools in organic synthesis, which the most common is bromolactonization reaction and bromoetherification reaction. Lactones is an important structural skeleton widespread in nature with rich pharmacological activities, and the most commonly used method for synthesizing the lactoneskeleton is halolactonization. Over the past 20 years, huge research efforts on this reaction have been made to improve the stereoselectivity and regionselectivity of the reaction. This type of reactions have many advantages, such as high yields, good selectivities, low toxicity, no pollution to the environment and so on, in line with the theme of green chemistry. This thesis outlines the recent progresses in the research of halolactonization reaction, and our study ofthe bromolactonizationreaction with unsaturated ureas as substrates and N-bromosuccinimide as an important source of bromine. Main contents include:the bromocyclization of N-phenylurea andN-tert-butylurea withN-bromosuccinimide.In this reaction, different configurations of the product can be obtained by changing the substituents on the nitrogen.The most important is that, through a simple and effective bromocyclization reactionwith good regioselectivities,six-membered ring heterocyclic compounds containinga pyrimidineketone structure are synthesized practically.