Stilbene derivatives biological activity

The synthesis of other biologically active thiazoles was described by Ohsumi et al. [50] and is shown in Scheme 16. Condensation of phosphonium bromide and 4-methoxy-3-nitrobenzaldehyde gave a 1 1 mixture of (Z)- and (-E)-stilbenes. ( )-stilbene 64 was purified by crystallization and then converted to bromohydrin 65 by NBS-H2O. Oxidation of the bromohydrin by DMSO-TFAA gave the bromoketone intermediate 66, which was condensed with thiocarbamoyl compounds in the presence of Na2C03 in DMF to give the corresponding 2-substituted thiazole derivatives (67a and b). Compound 67a... 

Synthesis of the phenyl derivative (138) was also described by Simoni et al. [60] and employs the same synthetic strategy as for the pyridine derivative (137) described in Scheme 34. No biological activity was reported for this compound, but it was included in order to provide a broader coverage of stilbene derivatives. 

Stilbene derivatives can be reduced with alkali metals in liquid ammonia. The reaction is usually performed in a homogeneous medium to give substituted diphenylethane compounds as a mixture of enantiomeric forms. However, there are compounds (particularly, biologically active ones) for which the stereospecificity of synthesis has decisive importance. A simple modification of the reduction method with an alkali metal in liquid ammonia was found (Collins and Hobbs 1983), which makes it possible to perform the process stereoselectively. The metal is not predissolved, as is usual, but is added in small portions without trying to make the reaction medium homogeneous. Stereoselectivity is ensured by carrying out the reduction on the surface of the metal and not in the solution bulk. 

It is widely accepted that polyphenols in wine are responsible for beneficial health effects (Sun et al. 2006). Particularly fran.y-resveratrol has been intensively studied and marked biological activities with regard to the prevention of cardiovascular disease and cancer have been reported (Ito et al. 2003). Other stilbenes also have properties similar to those of fran.y-resveratrol. Therefore, monitoring new stilbene derivatives in wine is of particular relevance (Guebailia et al. 2006). 

Dibromovinyl)uracil (18), prepared using dibromomethylenetriphenyl-phosphorane, can be transformed into a biologically active acetylene derivative. Various hydroxylated stilbenes, e.g, (19), have been obtained as shown. ... 

T. Hashimoto, M. Tori, and Y. Asakawa. A highly efficient preparation of lunularic acid and some biological activities of stilbene and dihydrostilbene derivatives. Phytochemistry 27 109 (1988). 

Many stilbene derivates (stilbenoids) are naturally present in plants. The most widely distributed stilbenoids are resveratrol, combretastatins, and pterostilbene. These agents are derived from terrestrial plants, microorganisms, marine organisms, and animals [1,2]. This chapter is a brief review on diverse biological activities of stilbenes in cells, organs, and animals. 

The coupling of iodo aryls with various olefins was conducted in the presence of palladium chloride (2.0 mol%) at ambient temperature under ultrasonic irradiation in water with yields between 43 and 90% [154], In situ formation of palladium nanoparticles was confirmed by transmission electron microscope and X-ray diffraction analyses, and the palladium nanoparticles could be reused for multiple reactions without significant loss of activity. Biologically relevant stilbene derivates, such as resveratrol, piceatannol and pinosilvine, were efficiently prepared with high regioselectivity and complete stereocontrol (TONS up to 10 , 0.01 to 0.50 mol% catalyst) [148], The activity of the oxime-derived palladacycle catalysts was compared in neat water with a DMF-water mixture, with similar... 

This protocol could be extended to a range of different ,/i-unsaturated carbonyl compounds and either activated or deactivated aryl iodides [22], An application of related Heck chemistry to the synthesis of methylated resveratrol (3,4, 5-trihydroxy-( )-stilbene) is shown in Scheme 6.4 [23]. The phytoalexin resveratrol exhibits a variety of interesting biological and therapeutic properties, among them activity against several human cancer cell lines. Botella and Najera have shown that the trimethyl ether of resveratrol (Scheme 6.4) can be rapidly prepared by microwave-assisted Heck reaction of the appropriate aryl iodide and styrene derivatives, using the same oxime-derived palladacycle as indicated in Scheme 6.3. 

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