Total Synthesis Of Breviscapine And New Methods For Synthesis Flavonols

Breviscapine,a flavonoid glycoside from Erigeron breviscapus(Vant.)HandMazz.Its components include scutellarin and apigenin-7-O-?-D-glucuronide.Scutellarin is the main active ingredient of Erigeron breviscapus drugs.The key steps of breviscapine synthesis process is the glycosylation.Traditional scutellarin glycosylation reaction is high costive,not efficient and conductive to industrial production.A general protocol for direct glucuronic linkages formation featuring Au(I)-catalyzed appropriately protected glucuronyl o-alkynylbenzoate-involved glycosylation reaction,as well as a concise approach for easy access of scutellarein prominent for the mild and efficient hydroxyl group installation via borylationoxidation reaction sequence from flavanone derivative has been established,based on which a novel route for scutellarin and analogue thereof has been devised.The developed strategies,among which the stepwise deprotection process is also included,guarantee the high whole synthetic efficiency,and definitely will find broad application in diversity-oriented synthesis of flavonoid glycosides analogues.Flavonoids are secondary metabolites of plants,which are widely distributed in almost all natural plants.Flavonol is a special flavonoid compound,also known as 3-hydroxyflavone.Its structure is complex and numerous,There are about 2,000 kinds,accounting for about 1/3 of the total number of flavonoids.Most of them have strong anti-oxidation,cardiovascular,anti-inflammatory,anti-cancer effects.In this paper,the flavonoid skeleton was re-synthesized from trihydroxyacetophenone,and the flavonoids were halogenated at C-3,and then coupled with the amide via the amino acid-mediated Goldberg reaction to the flavonoid C-3 halogen,and finally the amide was converted into ester by rearrangement reaction.At last,simple hydrolysis is carried out to obtain flavonols.