Development Of New Synthesis Method For Pharmaceutical Intermediates β-ionone Epoxide:Oxidation With Molecular Oxygen

5,6-Epoxy-β-ionone is the product of epoxidation of natural terpenoid β-ionone,which has unique industrial application value as an important pharmaceutical intermediate.Therefore,it is particularly important to develop a green synthesis of 5,6epoxy-β-ionone.In recent years,selenium-containing compounds and materials have attracted widespread attention due to the unique chemical and biological activities.In the field,investigations on selenium catalysis are unfolding.Selenium is a beneficial metabolizable element in human beings,so the tolerance of which residue in drugs is higher than that of the transition metals.Therefore,the development of an epoxidation method using selenium as catalyst to selectively synthesize 5,6-epoxy-β-ionone by molecular oxygen oxidation of β-ionone is a profound synthesis path that meets the requirements of pharmaceutical industry.In this thesis,three different molecular oxygen oxidation processes were designed,and all of them could produce β-ionone epoxide in the presence of selenium-containing catalysts.The specific studies are as follows:In chapter 2,three catalysts were prepared,and they were Se/SiO2-F,Se/SiO2,and SiO2-F.The catalytic activities of the materials were evaluated via their performances in β-ionone epoxidation.Se/SiO2-F was finally screened out to be a preferable catalyst for β-ionone epoxidation.A series of reaction conditions such as catalyst dosage and reaction temperature were regulated.The process employed oxygen as an oxidant,and was performed under simple and mild conditions,affording 5,6-epoxy-β-ionone with 73%selectivity.Control experimental results and XPS analysis showed that the reaction occurred via unique free radical mechanisms.In chapter 3,a Se/C-Fe catalyst was designed to catalyze β-ionone epoxidation.Compared to the materials in Chapter 2,the catalytic activity of Se/C-Fe was significantly enhanced.After screening of the catalyst dosage,reaction time,temperature,oxidant,etc.,the reaction could be optimized to produce 5,6-epoxy-βionone in 57%yield with 78%conversion.In chapter 4,a highly crystalline K-intercalation Se/C material was designed and employed as catalyst.In the reaction,N-hydroxyphthalimide（NHPI）was introduced as co-catalyst,while oxygen was employed as oxidant.After screening the catalyst dosage,co-catalyst dosage,reaction time and reaction temperature,the reaction could be optimized to produce 5,6-epoxy-β-ionone in 61%yield,while the conversion ratio ofβ-ionone was 92%.The total process is simple to operate,and the catalyst has excellent stability and recyclability.