Organic Selenium-catalyzed Depurination Reaction

Deoximation reaction is an important transformation in pharmacal industry.At present,the conventional deoximation technologies employ heavy metal catalysts,which are high cost and lead to the heavy metal residue in products.Organoselenium catalysts are highly efficient for oxidation reactions.The processes are metal-free and are suitable for pharmaceutical synthesis which has high requirement on the metal residue.This article introduces a new method for oxidative deoximation reactions:Catalyzed by organoselenium catalyst under aerobic conditions with H2O2 lead to the deoximation free of waste.The main results and conclusions are summarized as following three parts:Firstly,the article has studied what the influence will be of benzaldehyde oxime deoximation caused by solvent,selenium catalysts,temperature,and the amount of H2O2.Obtaining the optimal reaction conditions,the target product GC yield up to 99%,the selectivity of 96%.Under this condition,various of non-electron-substituted aromatic aldoximes were obtained in the medium yield and a strong electron donor-substituted aromatic aldoxime obtain relatively better yield,the acetoxime yield was only 17%.The next step will continuous study on the organic selenium catalyzed ketoxime deoxime reaction regulation.Secondly,the article has also studied what the influence will be of acetophenone oxime deoximation caused by solvent,temperature,amount of H2O2.and the response time.Reaction process conditions were investigated,such as:solvents,temperature,the amount of H2O2 and the reaction time.Selecting the best reaction condition,Aromatic ketoxime can be a good performance of the deoxime.Organicselenium catalyst can be recycled,recycling 5 times still have a relatively good catalytic effect.Based on the experimental verification mechanism and results,and the verification of 77Se NMR experiments,we explain the possible mechanism.Faced with the development requirements of new catalysts,we use selenium doped C3N4 to obtain novel selenium catalyst.Used to catalyze the oxidation of cyclohexene to produce 2-cyclohexenol and 2-cyclohexenone.Reaction process conditions were investigated,such as:solvents,temperature,the amount of catalyst and the reaction time etc.At present,it is still need further study on the yield and selectivity of 2-cyclohexenol and 2-cyclohexenone.Above all,we have developed a new kind of deoximation.The reaction is metal-free,additive-free and employs H2O2/air as the clean oxidant which shows a good practical value.In addition,a new type of selenium catalyst prepared herein,as extends the usage of selenium catalyst.