Study On The Synthesis Of A New Type Of O-Glycoside

O-glycosides are widely distributed in the plants,animals and microorganisms,not only have a variety in the structures,but also have significant pharmacological activities on the immune system,cardiovascular system and central nervous system.It is meaningful to study and synthesize new type of O-glycosides.In order to optimize the reaction conditions and synthesize phenolic glycosides,2,3,4,6-O-Tetraacetyl-?-D-glucopyranosyl bromide was prepared from D-glucose via acetylation,bromination.By using AlCl3,the 2-hydroxy-3,4-dimethoxybenzaldhyde was synthesized selectively starting from 2,3,4-trimethoxybenzaldhyde.The aldol reaction was carrided out and the chalcone products were obtained in the condition of alkali-absolute ethanol reaction with p-methoxyacetophenone and p-nitroacetophenone respectively.Then,three acceptors were obtained.While studying the glycosidation of the 2-hydroxy-3,4-dimethoxybenzaldhyde,3,4-dimethoxybenzaldhyde-2-O-?-D-acetyglucoside was synthesized at a relatively high yield by using anhydrous K2CO3 and tetrabutyl ammonium bromide.It is also applicable in accessing 3,4-dimethoxy-4'-nitro-1,3-diphenyl-2-propylene-1-ketone-2-Oacetyglucoside.By using methanol and anhydrous K2CO3,3,4-dimethoxybenzaldhyde-2-O-?-D-acetyglucoside was hydrolysed.Five new compounds were obtained.In order to explore the catalytic effects of trifluromethanesulfonates on Mukaiyama reaction and synthesize new O-glycoside with new method,it is originated by available Iron,Aluminum,Bismuth,Copper sulfate,after reacting with trifluoromethanesulfonic acid respectively,four trifluromethanesulfonates were afforded.The acetophenone tert-dimethylsilyl enol ether and p-nitroacetophenone tert-dimethylsilyl enol ether can be obtained at a higer yield,while acetophenone and p-nitroacetophenone were reacted with TBSOTf.By reacting with 2,3,4-trimethoxybenzaldhyde and 2-hydroxy-3,4-dimethoxybenzaldhyde in the presence of trifluromethanesulfonate,three new compounds were synthesized,moreover tracking out the effects of reactants and catalysts during the Mukaiyama reaction.The results suggested that the reaction activity of acetophenone tert-dimethylsilyl enol ether is inferior to p-nitroacetophenone tert-dimethylsilyl enol ether,the 2,3,4-trimethoxybenzaldhyde is superior to 2-hydroxy-3,4-dimethoxybenzaldhyde,Bi(OTf)3 has the best catalytic activity.Given that the reaction of acetophenone tert-dimethylsilyl enol ether and O-glycosides is rarely studied,the application of Mukaiyama reaction in the synthesis of new O-glycosides has yet not been reported.We tried applying Bi(OTf)3 to catalyze the Mukaiyama Reaction of acetophenone tert-dimethylsilyl enol ether,p-nitroacetophenone tert-dimethylsilyl enol ether with 3,4-dimethoxybenzaldhyde-2-O-?-D-acetyglucoside.The desired product was successfully synthesized with the yield of 43%.Nine new compounds were synthesized,their structures were confirmed by MS,IR,1H,13 C spectra.