569-92-6Relevant articles and documents
Selective methylation of kaempferol via benzylation and deacetylation of kaempferol acetates
Mei, Qinggang,Wang, Chun,Yuan, Weicheng,Zhang, Guolin
supporting information, p. 288 - 293 (2015/03/31)
A strategy for selective mono-, di- and tri-O-methylation of kaempferol, predominantly on the basis of selective benzylation and controllable deacetylation of kaempferol acetates, was developed. From the selective deacetylation and benzylation of kaempferol tetraacetate (1), 3,4′,5,-tri-O-acetylkaempferol (2) and 7-O-benzyl-3,4′5,-tri-O-acetylkaempferol (8) were obtained, respectively. By controllable deacetylation and followed selective or direct methylation of these two intermediates, eight O-methylated kaempferols were prepared with 51-77% total yields from kaempferol.
3-hydroxy-3-methylglutaryl flavonol glycosides from Oxytropis falcata
Wang, Shan-Shan,Zhang, Xiao-Jing,Que, Sheng,Tu, Guang-Zhong,Wan, Dan,Cheng, Wei,Liang, Hong,Ye, Jia,Zhang, Qing-Ying
experimental part, p. 1359 - 1364 (2012/09/25)
Five new 3-hydroxy-3-methylglutaryl (HMG) flavonol 3-O-glycosides, named oxytroflavosides A-E (1-5), and two new rhamnocitrin 3-O-glycosides, oxytroflavosides F and G (6 and 7) were isolated from the n-BuOH-soluble fraction of an EtOH extract of Oxytropis falcata together with seven known kaempferol glycosides (8-14), of which six were isolated from the genus Oxytropis for the first time. The structures of these compounds were elucidated by spectroscopic techniques and chemical methods. The absolute configuration of HMG in compounds 1-5 was determined to be S through spectroscopic analysis of the mevalonamide obtained by amidation and reduction of the HMG moiety. Compounds 1-10 were evaluated for anti-inflammatory activities using lipopolysaccharide-induced RAW 264.7 cells, but none of them showed inhibitory effects on NO production.
Chemical Studies on the Constituents of Hyphear Tanakae HOSOKAWA from Different Host Trees
Fukunaga, Takehiko,Nishiya, Koichi,Kajikawa, Ikuko,Watanabe, Yoshikuni,Suzuki, Nobuo,et al.
, p. 1180 - 1184 (2007/10/02)
The chemical constituents of Hyphear Tanakae HOSOKAWA epiphyting to four different host trees were examined.A new triterpene fatty acid ester (III) and four known flavonoid glycosides, rhamnocitrin-3-O-rhamnoside (V), kaempferol-3-O-rhamnoside (VI), rhamnetin-3-O-rhamnoside (VII), and quercetin-3-O-rhamnoside (VIII) have been isolated from the leaves and twigs of this plant epiphyting to Castanea crenata SIEB., together with fatty acids (I), phytosterol (II), and phytosterol-glucoside (IV).The present investigation has revealed that compounds II-V, VII, and VIII are contained in this plant irrespective of the host, among the four host trees, examined.Keywords - Hyphear Tanakae; misletoe; Loranthaceae; triterpene; lup-20(29)-ene-3β,7β,15α-triol; flavonoid; rhamnocitrin-3-O-rhamnoside; kaempferol-3-O-rhamnoside; rhamnetin-3-O-rhamnoside; quercetin-3-O-rhamnoside