The Synthesis Of Some Natural Chalcone Glycosides

The flavones are very important compounds in vegetables, fruit and the forage grass. They are also major active constituents of many Chinese medicines. With the in-depth study of the pharmacology, the flavonoids are reported possessing rich biological activities and chalcones, as an important branch of flavonoids, have gained much attention. This paper mainly discussed the total synthesis of three natural chalcones:4'-O-β-D-glucopyranosyl-4,3'-dimethoxychalcone (1),4'-O-β-D-glucoyranosyl-4-hydroxyl-3'-methoxychalcone (2), and4,4'-di-O-β-D-glucoyranosyl-3' methoxychalcone(3). And the synthesis of another natural product4'-O-(6"-O-galloyl-β-D-glucopyranosyl)-2',4-dihydroxychalcone (4) was conducted. Finally, the extraction technology for general flavones of Chickweed by orthogonal design was conducted. So, here are five chapters to introduce the detailed works.(1) IntroductionThe biological activities of the flavonoid glycosides are elaborated and make a conclusion upon synthesis methods of flavonoid glycosides. It is helpful to find new flavonoid glycoside molecules as the potential drugs on antioxidant, anticancer, antibacterial, antidepressants, antiallergy, antiaging and enhance to regulate the immune et al.(2) Total synthesis of three natural chalcone glycosidesAccording to the reverse synthetic route, we chose vanillina, p-hydroxylbenzaldehyde and1,2,3,4,6-Penta-O-acetyl-α-D-glucopyranose as the outset raw materials and designed the phase-transfer-catalyzed routines to synthesize the target chalcone O-glycosides. After vanillina was successively performed by MOMC1protection, Grignard reaction and PCC oxidation,3-methoxy-4-methoxymethoxybenzaldehyde was obtained. The chalcones were synthesized by Claisen-Schmidt condensation in methanol-potassium hydroxide system by3-methoxy-4-methoxymethoxybenzaldehyde and substituted p-hydroxylbenzaldehyde. After deprotection of MOM, chalcone O-glycosylation was conducted in the absence of heavy metal salts but in the presence of TBAB (tetrabutyl ammonium bromide)(or Aliquat 336) as the phase transfer cataly st. Later on further deacetylation, debenzylation,the target molecule s were Obtained.(3) Total synthe si s of4'-O-(6"-O-galloyl-β-D-glucopyranosyl)-2',4-dihydroxychalconeOn the bases of former working experience about the phase-transfer-catalyzed glycosides,we conducted further DCC esterification reaction on chalcone glycosides to acquire the target compound.(4) Synthesi s of α,β-un saturated ketone s by Grinding MethodU sing NaOH-Na2CO3as the catalysts Claisen-Schmidt conden sation of citral with aromatic ketene s was proceeded by simple mixing and grinding to synthe size a serie s of(2E,4E)-5,9-dimethyl-2,4,8-triene-1-phenyl ketone derivatives.