Phenols isoflavones

These experiments and observations clearly prove the importance of QAs for lupines, but it should not be forgotten that other secondary metabolites, such as phenolics, isoflavones, terpenes, saponins, stachy-ose, erucic acid, and phytic acid, are also present in lupines and may exert additional or even synergistic effects. 

The isoflavone 406 is prepared by the indirect a-phenylation of a ketone by reaction of phenylmercury(II) chloride with the enol acetate 405, prepared from 4-chromanone[371]. A simple synthesis of pterocarpin (409) has been achieved based on the oxypalladation of the oriho-mercurated phenol derivative 408 with the cyclic alkene 407[372,373]. 

Food and plant phenolics are commonly detected using DAD detectors (Tan and others 2008). Photodiode array detection allows collection of the entire UV spectrum during the elution of a chromatographic peak, which makes it possible to identify a phenolic compound by its spectra. Simple phenols, phenolic acids, flavanones, benzophenones, isoflavones, and flavan-3-ols have maximum absorbance at 280 nm, hydroxycinnamic acids at 320 nm, flavonols, flavones, and dihydroflavonols at 365 nm, and anthocyanins at 520 nm (Ibern-G6mez and others 2002 Merken Hand Beecher 2000). Hydrolyzable tannins show a characteristic shoulder at 300 nm, suitable for identifying them (Arapitsas and others 2007). For stilbenes, maximum absorbance of trans-forms are at 306 nm and at 285 nm for cA-forms (Lamuela-Raventos and others 1995). 

New detection methods of phenolic compounds are being developed. Based on the principle of the enzyme-linked immunosorbent assay (ELISA), a method has been developed to quantify phenolic compounds such as isoflavones (Vergne and others 2007). 

LI. Labow, R. S., and Layne, D. S., The formation of glucosides of isoflavones and of some other phenols by rabbit liver microsomal fractions. Biochem. J. 128, 491-497 (1972). 

Other investigators have found apiose in a wide variety of plants (see Table I). Apiose has usually been isolated as glycosides in which it is linked to compounds of low molecular weight. These include only derivatives of flavone, isoflavone, phenol, and anthra-quinone (see Table I). 

The ring closure of orf/io-substituted phenols is a route to production of benzo[6]furans on an industrial scale. The natural benzo[6 ]furan derivatives karanjin, pongapin, khellin and visnagin have been prepared via the respective o-hydroxyarylacetaldehydes, whilst an extension to the cyclization of o-hydroxybenzyl alkyl ketones has made it possible to synthesize polycyclic benzo[6]furans under the influence of demethylating and dehydrating media. Pterocarpans have been synthesized from suitable isoflavones by this route. 

Several groups have described syntheses of chromones which involve the use of enamines. Reaction of salicylaldehyde with 1-morpholinocyclohexene gives the chromanol which is readily oxidized to the chromone (66JOC1232). Other examples include the use of 1-morpholino-l-phenylethylene which gives flavene, whilst N-styrylmorpholine yields isoflavone. The enamine reaction is considered to proceed in the normal manner with subsequent cyclization involving the neighbouring phenolic group (Scheme 163). 

Sesamex [51-14-9] (Sesoxane) (30) is a synergist oflow toxicity, acute oral LD50 (rat) = 2000-2270 mg/kg, for pyrethrins and allethrin. 6,7-Dihydroxy 4-methylcoumarin has been offered as an antioxidant for phenolics and polymers, and as an anthelmintic. 2,4,5-Trihydroxybutyrophenone has been available as an antioxidant and light stabilizer for polyolefins, waxes, and foods. IsofLavones, eg (31), have been patented as components of antioxidant compositions for foods and cosmetics (qv) (97). 

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