10.1016/0031-9422(90)85105-O
The research aimed to investigate the flavonoid compounds present in New Zealand Libocedrus species, specifically Libocedrus bidwillii and L. plumosa, and to assess their chemotaxonomic significance. The study's purpose was to support or challenge the existing classification of these species within the Cupressaceae family by analyzing their flavonoid profiles. The conclusions drawn from the research indicated that while the two Libocedrus species shared similar flavonoid types, they were distinct enough to be differentiated, with L. plumosa characterized by the presence of myricetin 3-rhamnoside and L. bidwillii by the presence of a di-acylated quercetin 3-rhamnoside. The chemicals used in the process included various flavonoids such as kaempferol, quercetin, apigenin, luteolin, amentoflavone, and biflavonoids like 7-O-methyl-2,3-dihydroamentoflavone.
10.1016/0031-9422(90)85389-W
The research focuses on the isolation and identification of chemical compounds from specific plant sources. In the first study, two new flavonol glycosides, kaempferol 3-rhamnoside-4’-xyloside and kaempferol 3-rhamnoside-7-xyloside, along with kaempferol, isorhamnetin, and quercetin, were identified from the fruits of Chenopodium ambrosioides. The structures of these compounds were established using spectroscopic and chemical evidence, including techniques such as IR spectroscopy, NMR spectroscopy, and mass spectrometry. The study also involved the use of various solvents and reagents for extraction, isolation, and chemical modifications of the compounds. In the second study, a new moskachan, chalepimoskachan, along with other coumarins and alkaloids, was isolated from the roots of Ruta chalepensis. The research involved the use of chromatographic methods and spectroscopic techniques to identify and characterize these compounds.
10.3762/bjoc.11.135
The study presents an efficient semi-synthetic approach to produce the bioactive flavonoid glycoside icariin from kaempferol through an eleven-step process with a 7% overall yield. The key steps involve the selective methylation of kaempferol's 4′-OH group, a para-Claisen–Cope rearrangement catalyzed by Eu(fod)3 in the presence of NaHCO3 to achieve 8-prenylation, and the glycosylation of icaritin. The researchers optimized the selective methylation and rearrangement processes to improve yields and selectivity, ultimately synthesizing icariin and its related compound icariside I with 7% and 16% overall yields, respectively. The synthesized compounds were fully characterized using various spectroscopic techniques, confirming their structures and bioactivity.
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