Studies On The NBS-promoted Three-membered Ring Opening Reaction And Synthesis Of Nitrocaine

N-bromosuccinimide(NBS),as a common chemical reagent in the laboratory,is cheap and readily available,and frequently used in bromination reactions.It could be used as a potential bromine cation prescuor to participate in the electrophilic addition reaction,and could also be involved in the free radical reaction as a bromine free radical source.Cyclopropene is the smallest unsaturated cyclic compound with large ring tension and high reactivity.Its ring-opening products could be used in biological synthesis and pharmaceuticals.Thus the ring-opening reaction of cyclopropylenes promoted by cheap reagent is of great significance for the development and preparation of drugs.Procaine is a clinical drug mainly used for infiltration anesthesia,block anesthesia,etc.The combination of procaine hydrochloride and other drugs can be used for anti-aging therapy.With the deepening of clinical drug use and people's unremitting pursuit of anti-aging,the market demand of the drug is gradually increasing.Among them,nitrocaine is an important precursor for the synthesis of procaine.This paper is divided into three chapters:The first chapter is a literature review,and the organic chemical reactions promoted by NBS are summaried.The reactions of NBS as bromination reagent,catalyst and oxidant are mainly introduced.In the second chapter,under the catalysis of NBS,cyclopropene carboxylate undergoes regioselective oxidation and ring opening to form ?,?-unsaturated carboxylic acid ester compounds.The reaction has the advantage of simple operation,mild reaction conditions,and high yields.The obtained ?,?-unsaturated carboxylic acid ester compounds are important pharmaceutical intermediates and have wide applications in the synthesis of natural products and drugs.The third chapter mainly optimizes the synthetic method of nitrocaine by the transesterification method and the direct esterification method,respectively.And finally the optimal conditions for the synthesis of nitrocaine was established.