5-Alkylresorcinols from Hakea trifurcata, that cleave DNA.
摘要:
A dichloromethane extract of Hakea trifurcata that mediated relaxation of phi X174 replicative form DNA at micromolar concentrations in the presence of CU2+ was resolved into six active components by bioassay-guided fractionation. Five of the active principles were characterized structurally and shown to be 5-alkylresorcinol derivatives. These included 1,3-dihydroxy-5-tridecylbenzene (1), 1,3-dihydroxy-5-(cis-8'-pentadecenyl)benzene (2), 1,3-dihydroxy-5-[14'-(3'',5''-dihydroxyphenyl)-cis-6'-tetradecenyl]benzene (3), 1,3-dihyroxy-5-[1 4'-(3'',5''-dihydroxyphenyl)tetradecyl]benzene (4), and 1,3-dihydroxy-5-[16'-(3'',5''-dihydroxyphenyl)-cis-8'-hexadencenyl]benzene (5). The structures of these five natural principles were confirmed by total synthesis; compounds 1-5 were accessible from 3,5-dimethoxybenzaldehyde in overall yields of 59%, 27%, 15%, 16%, and 13%, respectively.
The rhodium-catalyzed deoxygenation and borylation of ketones with B2pin2 have been developed, leading to efficient formation of alkenes, vinylboronates, and vinyldiboronates. These reactions feature mild reaction conditions, a broad substrate scope, and excellent functional-group compatibility. Mechanistic studies support that the ketones initially undergo a Rh-catalyzed deoxygenation to give alkenes
Solid-Phase Reactive Chromatography (SPRC): A New Methodology for Wittig and HornerâEmmons Reactions on a Column under Microwave Irradiation
作者:Saada C. Dakdouki、Didier Villemin、Nathalie Bar
DOI:10.1002/ejoc.200901032
日期:2010.1
A newmethodology named solid-phasereactivechromatography (SPRC), which combines reaction, separation, and purification into a single unit for the preparation of small samples, is described. This method was illustrated in the synthesis of some natural bioactive compounds, namely, methoxylated analogues of resveratrol, alkylresorcinols, and 5-aryl-2,4-pentadienoates, over a column of alumina-KF under
Both enentiomers of hiburipyranone, a cytotoxic metabolite of marine sponge, was synthesized employing Sharpless' asymmetric dihydroxylation as a key step and absolute configuration of the natural compound at C-3 position was determined to be R.(C) 1998 Elsevier Science Ltd. All rights reserved.
Design of Negative and Positive Allosteric Modulators of the Cannabinoid CB<sub>2</sub> Receptor Derived from the Natural Product Cannabidiol