Study On The Synthesis Of 1,2:4,5-Di-O-isopropylidene-D-erythro-2,3-hexodiulo-2,6-pyranose(D-epoxone)

We studied and optimized the preparation of 1,2:4,5-Di-O-isopropylidene-D-erythro-2,3-hexodiulo-2,6-pyranose(D-Epoxone)from D-Fructose.D-Epoxone is a fructose-derived chiral ketone catalyst used widely in scientific research for the asymmetric epoxidation of olefins,particularly olefins with no allylic alcohol groups.The epoxidation of olefins using D-Epoxone offers excellent asymmetric selectivity and has great potential in chemical manufacturing and in particular the preparation of pharmaceutical intermediates.One of the factors that limited the large scale use of D-Epoxone is the difficulties in its preparation,which is more serious when being moved from grams scale to kilogram scale,this has a lot to do with the reaction parameters as well as the choices of oxidants in the second steps,in particular the treatment of the oxidation reaction.We used D-Fructose as the starting material,and we have examined the parameters for the first step of isopropylidination of the sugar,which includes the reaction time,temperature and etc that influence the distribution of the thermokinetic product 1,2:4,5-Di-O-isopropylidene-D-fructopyranose and thermodynamic 2,3:4,5-Di-O-isopropylidene-D-fructopyranose,with the yield of the desired 1,2:4,5-Di-O-isopropylidene-D-fructopyranose being about 50%.On the oxidation of the 1,2:4,5-Di-O-isopropylidene-D-fructopyranose we examined the use of pyridinium chlorochromate(PCC),pyridium dichromate(PDC)and ruthenium tricloride–Sodium periodate systems for preparation of D-Epoxone,with various conditions and reactions treatment with kilogram scales.We used the microencapsulation technology to make a urea-structure encapsulated ruthenium tricloride system with toluene diisocyanate.In this encapsulated ruthenium tricloride system,the metal catalyst can be recycled and reused without much loss of efficiency,which not only reduced the pollution to the environment,but also reduced the cost of precious metal catalyst.In summary,we have optimized the preparation of D-Epoxone,which paved the way for further improvement and industrial application of this fructose-derived chiral ketone catalyst.