Hydroxystilbenes derivatives

Oxidation of Hydroxystilbene Derivatives with Nitrobenzene and Cop-per(II). To serve as / -l lignin model compounds, some 1-(4-hydroxyphenyl)-2-(4,-substituted phenyl)ethanols, (4), (Figure 2) were synthesized ( ). The / -l lignin model was chosen, since it is the only common lignin unit structurally suitable for substituent-reactivity studies on oxidation rates. In an effort to study... 

Ohguchi K et al. (2003) Effects of hydroxystilbene derivatives on tyrosinase activity. Biochem Biophys Res Commun 307(4) 861-863... 

Stojanovic S, Brede O. (2002) Elementary reactions of the antioxidant action of trans-stilbene derivatives Resveratrol, pinosylvin and 4-hydroxystilbene. Phys Chem Chem Phys A 757-764. 

Methanol addition results on irradiation of 2,3-dimethylbut-2-ene in a mixture of 1,4-dicyanobenzene and phenanthrene in the presence of acrylonitrile or methyl acrylate. Inoue and co-workers have studied the enantio-differentiating addition of alcohols to the 1,1-diphenylethene derivatives (52). The reactions are sensitized by the naphthalenecarboxylates (53) and (54), where the R groups are saccharide moieties. The ee of the products (55) is influenced by steric, electronic and solvent effects. Efficient addition of water to 3-hydroxystilbene can be brought about on irradiation in acetonitrile-water mixtures.Pincock has highlighted the importance of the discovery in 1973 of the formation of the radical cation of 1,1-diphenylethene. Grainger and Patel have described a new photochemical approach to cuparene (56). The reaction involves the electron-transfer induced cyclization of the styrene... 

A one-pot two-step synthesis of hydroxystilbenes with trans selectivity was developed through a modified Perkin reaction between benzaldehydes and phenylacetic acids bearing 4- or 2-hydroxy substitution at the aromatic ring [67]. The reaction was performed under mild conditions in the presence of piperidine-methylimidazole and polyethylene glycol under microwave irradiation. As a result, 71% yield of ( )-4-chloro-4 -hydroxy-3 -methoxystilbene from 4-hydroxy-3-methoxybenzaldehyde and 4-chlorophenylacetic acid was obtained. A microwave-induced one-pot process for the preparation of arylethenes has been patented [118]. For the preparation of a series of arylethenes (I R -R = H, OH, OMe, AcO, halo, NO2 R, R, R = OH, AcO R= H, substituted aryl), reaction of 2- or 4-hydroxy substituted cinnamic adds or derivatives in the presence of a base, under reflux or microwave irradiation, has been used. For example, a mixture of a-phenyl-4-hydroxy-3-methoxycinnamic acid, NaHC03, methylimidazole, and polyethylene glycol was microwaved at 200 W and 180 °C for 10 min to give 96% 4-hydroxy-3-methoxystilbene. 

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