Two new phenolic carboxylic acid esters n-butyl eucomate(1) and methyl eucomate (2) and six known compounds eucomic acid(3), 3-β-acetyl-taraxerol (4), friedelin(5),lupenone(6),methyl linoleate(7) and methy...Two new phenolic carboxylic acid esters n-butyl eucomate(1) and methyl eucomate (2) and six known compounds eucomic acid(3), 3-β-acetyl-taraxerol (4), friedelin(5),lupenone(6),methyl linoleate(7) and methyl oleate(8) were isolated from the stems of Opuntia vulgaris Mill(Cactaceae). Their structures were determined on the basis of spectral methods. Compounds 3,4,6,7,8 were isolated for the first time from this plant.展开更多
Phenolic acid esters of cellulose show antioxidative and antimicrobial properties,which are very interesting for a variety of applications,including packaging and medicine.In contrast to simple mixing or encapsulation...Phenolic acid esters of cellulose show antioxidative and antimicrobial properties,which are very interesting for a variety of applications,including packaging and medicine.In contrast to simple mixing or encapsulation of phenolic compounds in polymeric materials,covalent linkage to the polymer backbone enables long-term activity and reduces toxicity because leaching of phenolic moieties is avoided.For the synthesis of such polymers,chemical modification of cellulose by polymer analogous reactions must be performed.Cellulose esters of ferulic-,4-hydroxybenzoic-,vanillic-,protocatechuic-,and gallic acids are synthesized by two different approaches.On the one hand,transesterification of cellulose with corresponding methyl esters in DMSO/DBU/CO_(2)is appropriate to synthesize derivatives possessing only one phenolic hydroxyl group,e.g.hydroxybenzoates and vanillates.On the other,conversion with TBS-protected imidazolides is carried out,which allows the synthesis of cellulose esters possessing multiple phenolic hydroxyl groups such as protocatechuates and gallates.展开更多
文摘Two new phenolic carboxylic acid esters n-butyl eucomate(1) and methyl eucomate (2) and six known compounds eucomic acid(3), 3-β-acetyl-taraxerol (4), friedelin(5),lupenone(6),methyl linoleate(7) and methyl oleate(8) were isolated from the stems of Opuntia vulgaris Mill(Cactaceae). Their structures were determined on the basis of spectral methods. Compounds 3,4,6,7,8 were isolated for the first time from this plant.
基金Gefördert durch die Deutsche Forschungsgemeinschaft(DFG)-Projektnummer 451990883(funded by the Deutsche Forschungsgemeinschaft(DFG,German Research Founda-tion)-project number 451990883).
文摘Phenolic acid esters of cellulose show antioxidative and antimicrobial properties,which are very interesting for a variety of applications,including packaging and medicine.In contrast to simple mixing or encapsulation of phenolic compounds in polymeric materials,covalent linkage to the polymer backbone enables long-term activity and reduces toxicity because leaching of phenolic moieties is avoided.For the synthesis of such polymers,chemical modification of cellulose by polymer analogous reactions must be performed.Cellulose esters of ferulic-,4-hydroxybenzoic-,vanillic-,protocatechuic-,and gallic acids are synthesized by two different approaches.On the one hand,transesterification of cellulose with corresponding methyl esters in DMSO/DBU/CO_(2)is appropriate to synthesize derivatives possessing only one phenolic hydroxyl group,e.g.hydroxybenzoates and vanillates.On the other,conversion with TBS-protected imidazolides is carried out,which allows the synthesis of cellulose esters possessing multiple phenolic hydroxyl groups such as protocatechuates and gallates.
