¦¢-nitrostyrene With N, N-dibromo The Wulai Sugar Ambroxol Addition Reaction

The aminohalogenation is a reaction for the converting common petroleum olefins into vicinal haloamine products by the addition of amine and halogen moieties onto carbon-carbon double bonds. the animobromination are important building blocks in organic and medicinal chemistry, because they can be easily converted into amino acids or aziridinecarboxylates by replacement of the halogen in both intramolecular and intermolecular reactions, May be further converted into numerous useful functional groups, such as the alkamine, diethylenetriamine, etc. It is also of considerable significance, which vicinal haloamino products are relatively research on biochemical and drug chemical as well as pharmaceutical molecular synthesis for 40 years. The synthesis and nature research of vicinal haloamino product become an active research field in the world. Meanwhile, the confusing mechanism hypothesis of the original aminohalogenation may also have attributed to this situation. So researchers are interested in the topics as follow so far:1. The research for screening various nitrogen/halogen sources.2. The research for explore new catalysts.3. The research for expanding substrate scopes.4. Asymmetric synthesis of aminohalogenation.In the past two decades, many aminohalogenation processes have been developed for a variety of simple olefins and electron-deficient olefins, includingα,β-unsaturated ketones, cinnamates, and unsaturated nitriles. The aminohalogenation ofβ-nitrostyrenes has not been well documented so far. Adductive products of aminohalogenation forβ-nitrostyrenes could be converted into diamine and other useful compounds.Basd on this situation, in this paper, we have developed a new system for the aminobromination ofβ-nitrostyrenes with N,N-dibromourethane(DBU) as the nitrogen/bromine sources, The advantages of this system are mild, simple operation, good reaction selectivity, wide range of products, and the absolute regioselectivity. Using this method, we have synthesized 21 samples of haloamino products ofβ-nitrostyrene derivatives. Affacting factor for the aminobromination ofβ-nitrostyrenes have been investgated. The reaction mechanism was speculated according to the reaction result.The first chapter is a summary on research progress of the aminohalogenation. It contains halogen and nitrogen sources, catalyst, the substrates study condition of aminobromination reaction at various systems.In the chapterⅡ, experimental design and exploration of this issue. The 21 kind of typicalβ-nitrostyrnes compounds were synthesized which were applied to aminohalogenation. We also designed to synthesize the related nitrogen source/halogen sources, which were used for aminohalogenation and explorated the aminohalogenation of thisβ-nitrostyrnes.In the chapterⅢ, the new method of variousβ-nitrostyrenes of haloamino addition reaction have been developed, in which N, N-dibromourethane is as nitrogen/halogen sources. Theβ-nitrostyrenes (1-phenyl-2-nitroethene) of haloamino addition reaction was performed handily in CH3CN at room temperature without both catalyst and special protection of inert gas in which the absolutely regioselective products and excellent yields (up to 97%) were obtained; For theβ-methyl analogue, the reaction proceeded smoothly under the same conditions to provide the aminobrominated products in 48% yields, The possible reason are due to stereo-hindrance effect of theβ-CH3. In the presence of 20 mol% K2CO3, theβ-methyl analogue gave the desired adductive product in 71% yield within 24 h. We mainly investigated the reaction activity and selectivity of different substrates influenced by substituent and structure in the optimum conditions. According to the experiments, drastic difference in both reactivity and selectivity of the reactions was observed.In this paper, N, N-dibromourethane as nitrogen/halogen sources, the aminohalogenation reaction ofβ-nitrostyrene derivatives is easy to be carried out under room temperature. The operation is simple and it reacts under mild reaction conditions with good yield. The products structure were characterized by elemental analysis,1H NMR,13C NMR and X-ray crystallography.