Study On Synthesis Technology Of Hydroxypropyl Tetrahydropyranol

Hydroxypropyltetrahydropyranol,also known as Bose,is a C-glycosyl derivative.Because of its wide biological activity,it can activate the synthesis of mucopolysaccharide(GAGs),and promote the production of hyaluronic acid and collagen.Because it can resist skin aging,dehydration and other symptoms,it can also improve the adhesion between dermis and epidermis.It can induce the synthesis of dermis and epidermal structural components,promote the regeneration of damaged tissues,help maintain the elasticity of dermis,prevent skin aging,so it is widely used in food,biology,medicine,cosmetics and other fields.Bose is easy to biodegradate,will not accumulate in organism,no toxicity,and has a good market development prospect.Firstly,the reaction of D-xylose with acetylacetone in alkaline aqueous medium was studied.During the reaction,it forms β-C-glycosyl monomer by Knoevenagel reaction between activated methylene and bare aldose,then Michael type intramolecular addition and Claisen aldol condensation.The second step is to reduce ketones in secondary alcohols in aqueous medium.In the experiment,the effects of the selection of raw materials,alkaline conditions,the selection and amount of solvent,the order and speed of solution dropping,the amount of acetylacetone,reaction time and temperature on the experimental results were mainly investigated,and the corresponding optimization of the synthesis scheme was carried out.The results showed that the yield of the product was the highest when xylose and acetylacetone were reacted in excess alkaline condition(2 times of the molar amount of sodium hydroxide)for 1 h.It is necessary to control the acidity and basicity of the reaction and keep the p H at about 8-9 in the process of dropping acetylacetone,so the dropping speed of sodium hydroxide solution should be controlled well.Compared with xylose,arabinose has limited utility,which is mainly determined by the stereochemical properties of various sugars.In addition,the selection of active methylene is also limited,because only acetylacetone(2,4-pentadienone)with simple methyl residue can obtain higher yield.The consumption of raw materials and the formation of products were detected by liquid chromatography.The crude product was extracted with ethyl acetate,the water layer was collected,and the solvent was distilled by rotary distillation to obtain brown oil.The product was then reduced by sodium borohydride to form 1-C-(β-D-xylopyranosyl)-2-hydroxy-propane,which was called bosein.In order to avoid the synthesis of mixtures of c-glycosylketones with different chain lengths,diketo reagents must be symmetrical.The properties of the base also have a significant effect on the yield and reaction time.At lower temperature,Na OH is the most effective base for shortening reaction time and quantitatively forming β-C-xylosyl products.