Study On The Application Of Pyridine Carboxylic Acid Nitroxide Ligands In The Catalytic Oxidation Of Alcohols And The Oxidative Ammination Of Alcohols To Nitriles

The oxidation of alcohols to the corresponding aldehydes/ketones and oxidative amination of alcohols to nitriles are quite important reactions in organic and medical synthesis.With water as solvent or under solvent-free conditions,molecular oxygen or peroxides as the oxidant to realize these catalytic transformations is environmentally friendly,pollution-free,and also conforms to the requirements of green chemistry.In this thesis,an catalytic system composed of bidentate N,O-containing ligand sodium pyridine-2-carboxylate,CuBr,TEMPO and K₂CO₃ was developed to catalyze the oxidation of alcohols to the aldehydes.The optimized reaction conditions were obtained through the screening conditions,which were:CuBr 5 mol%,ligand 5 mol%,TEMPO 5 mol%,K₂CO₃ 10 mol%,H₂O 2 mL,reaction temperature 25°C.Subsequently,the applicability of the catalytic system was investigated.The results showed that the catalytic system can efficiently catalyze oxidation different aromatic alcohols to their corresponding aromatic aldehydes.A new catalytic system composed of CuCl/L/TEMPO for the catalytic oxidation of alcohols to nitriles was found.Under solvent-free conditions,with benzyl alcohol as the model substrate and aqueous ammonia as nitrogen source,the optimized conditions were obtained through the screening conditions,which were:CuCl 9 mol%,L 6 mol%,TEMPO 8 mol%,reaction temperature 50°C.Subsequently,the applicability of the catalytic system was investigated by the oxidative amination reaction of different benzylic alcohols.The results showed that the system could efficiently catalyze aerobic oxidation of various benzyllic alcohols with electron-donating or electron-withdrawing groups on the ortho or para of the benzylic alcohols to their corresponding aromatic nitriles.Under solvent-free conditions,a new catalytic system for the catalytic oxidation of alcohols to ketones was developed using Mn?OAc?₂ as catalyst,2,6-pyridinedicarboxylic acid as ligand,TBHP as oxidant.The optimized conditions were obtained through the screening conditions,which were:2 mol%Mn?OAc?₂,3.5mol%2,6-pyridinedicarboxylic acid,molar ratio of substrate to TBHP 1:2,reaction temperature 100°C.Under the optimum conditions,the system was applied to the catalytic oxidation of different secondary alcohols.The results showed that most of secondary alcohols can be oxidized to their corresponding aromatic ketones.