background and overview[1]
methyl 3,4-dihydroxyphenylacetate can be used to prepare hydroxytyrosol. hydroxytyrosol, whose chemical name is 3,4-dihydroxyphenylethanol, is a hydroxyaromatic compound. natural hydroxytyrosol rarely exists in free form in nature. it is only found to be obtained by enzymatic hydrolysis of oleuropein by β-glycosidase and esterase during the ripening process of olive fruits. hydroxytyrosol is a polyphenolic natural product. the strong antioxidant properties and free radical scavenging ability of its o-diphenolic hydroxyl group make it have some biological activities that are beneficial to human health, such as anti-tumor, antibacterial, and anti-inflammatory. as well as the preventive effect on cardiovascular and cerebrovascular and sugar and lipid metabolism diseases.
preparation[1]
(1) add 520g of dilute hydrochloric acid aqueous solution with a mass fraction of 10% into the reaction vessel, add 100g of 3,4-dimethoxyphenylacetic acid and 1.53g of glacial acetic acid under stirring at room temperature; after the addition is completed, at 80 react at ℃ for 6 hours; take a sample and use hplc to detect the complete reaction of the raw materials; lower the reaction solution to 60°c, distill the water under reduced pressure, add 200ml of isopropyl ether to the remaining oil, and then freeze it in the refrigerator (0°c) overnight. a white solid precipitated and was filtered. the filter cake was washed with isopropyl ether and dried at 55°c to obtain pure 3,4-dihydroxyphenylacetic acid, 83.5g, with a yield of 96.9%.
(2) add 100 ml of methanol to a reaction vessel, add 83.5 g of 3,4-dihydroxyphenylacetic acid with stirring at room temperature, and after it is completely dissolved, add 4.98 g of concentrated hydrochloric acid (mass fraction: 36% ); after the addition is completed, react at 56°c for 1 hour; take a sample, and detect the complete reaction of the raw materials by hplc; lower the reaction solution to room temperature, concentrate under reduced pressure to recover methanol, add 100 ml of water to the remaining oil, and then use methyl tert-butyl extract with ether, collect the organic layer, dry it, and concentrate to dryness to obtain 3,4-dihydroxyphenylacetic acid methyl ester, 89.5 g, with a yield of 98.4%.
main reference materials
[1]cn201910495320.1 preparation method of hydroxytyrosol
