Naturally Occurring Isoflavonoids (1855–1981)

Ingham, John L.

doi:10.1007/978-3-7091-8703-6_1

Cited by 49 publications

(11 citation statements)

References 525 publications

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“…IF 's, in contrast to flavonoids, are of limited taxonomic distribution in the higher plants, being confined largely to the Papilionatae sub-family of the Legum inosae. They possess distinct biological activities including fish poisoning, insecticidal, spore germ ination inhibiting, hemolytic, and estrogenic effects [1]. Their UVspectra are different from flavonoids in showing a strong absorption in the region 245 to 270 nm (band II) and a rather weak band or shoulder with log e between 3.6 to 4.1 in the region of 300 to 340 nm.…”

Section: Introductionmentioning

confidence: 99%

The Absorption and Fluorescence of Isoflavones and the Effect of Shift Reagents

Wolfbeis

Fiirlinger

Jha³

et al. 1984

Zeitschrift Für Naturforschung B

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The absorption and fluorescence maxima of 20 isoflavones have been determined in methanol solution and the effect of addition of water, 50% sulfuric acid, aluminium trichloride, borax, sodium acetate, ammonia and sodium hydroxide has been studied. The following findings may be useful in the structure elucidation of naturally occurring isoflavones: (a) 5-Hydroxyisoflavones have band I absorption maxima around 335 nm. 6-hydroxyisoflavones between 310 and 330 nm, and others below 310 nm. (b) Addition of water produces practically no shift in the absorption spectra, but - unlike other hydroxyisoflavones - can give distinctly longwave shifted new fluorescence bands with 7-hydroxyisoflavones. (c) Addition of sodium acetate gives rise to anion absorption of 7-hydroxyisoflavones and to partial anion absorption of 6-hydroxyisoflavones; the spectral maxima of 5-hydroxyisoflavones remain practically unchanged, (d) Ammonia gives rise to anion absorption of both 6- and 7-hydroxyisoflavones, but not of the 5-hydroxy isomers, (e) Sodium borate is a useful reagent to identify 6,7-dihydroxyisoflavones by virtue of its ability to form a chelate complex with an absorption maximum that is different from the anion absorption, (f) Aluminium trichloride forms complexes with both 5-hydroxy- and 6,7-dihydroxyisoflavones with distinct absorption maxima, (g) 5,7-D ihydroxyisoflavones may be recognized by addition of ammonia, which does not result in a longwave shift, but rather in an intensification of the longwave absorption band, (h) 6-H ydroxyisoflavones can be differentiated from the 7-hydroxy isomers by their longwave shifts (4 0-60 nm) following addition of ammonia. The respective shifts of the 7-hydroxy isomers are smaller, (i) 5-H ydroxyisoflavones are practically non-fluorescent. while others have fairly strong fluorescences, (j) The absorption and fluorescence maxima of isoflavones give unique combinations which may be useful in their identification, (k) Addition of aluminium chloride makes the non-fluorescent 5-hydroxyisoflavones fluorescent. (1) As in the case of absorption, 6,7-dihydroxyisoflavones form complexes with borate possessing fluorescence bands with maxima different from those of the anion bands

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Section: Introductionmentioning

confidence: 99%

The Absorption and Fluorescence of Isoflavones and the Effect of Shift Reagents

Wolfbeis

Fiirlinger

Jha³

et al. 1984

Zeitschrift Für Naturforschung B

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“…The pesticidal and insecticidal activities of T. vogelii are likely to be due to the presence of rotenoids (Ingham, 1983;Marston et al, 1984). T. vogelii can also have serious impacts on aquatic ecosystems by affecting organisms other than the target species (Beal and Anderson, 1993).…”

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confidence: 99%

Laboratory evaluation of aqueous leaf extract of Tephrosia vogelii against larvae of Aedes albopictus (Diptera: Culicidae) and non-target aquatic organisms

Huang

Wang

et al. 2015

Acta Tropica

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“…First, we found that reaction of 2-fluorobenzaldehyde (44) with N-tosyl prenylamine (45) under classic SNAr conditions, 13 followed by 9-catalysed RCCOM led to the formation of adduct 11 in 59% yield over two steps. Second, we found that RCCOM of substrate 46 under standard conditions followed by solvent exchange to CH2Cl2 and subjection to Lewis acidmediated cycloaddition with quinone 47 according to the literature procedure 14 furnished the azapterocarpan analogue 48 15 in 52% yield over the two telescoped steps. In conclusion, we have developed a novel approach to the synthesis of dihydroquinolines via hydrazine-catalysed ringclosing carbonyl-olefin metathesis of N-prenyl-2aminobenzaldehydes.…”

Section: Ring-closing Carbonyl-olefin Metathesismentioning

confidence: 91%

Synthesis of 1,2-Dihydroquinolines via Hydrazine-Catalysed Ring-Closing Carbonyl-Olefin Metathesis

Zhang¹,

Sim²,

MacMillan³

et al. 2019

Preprint

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The synthesis of 1,2-dihydroquinolines by the hydrazine-catalysed ring-closing carbonyl-olefin metathesis (RCCOM) of N-prenylated 2-aminobenzaldehydes is reported. Substrates with a variety of substitution patterns are shown, and the compatibility of these conditions with a range of additives is demonstrated. With an acid-labile protecting group on the nitrogen atom, in situ deprotection and autoxidation furnishes quinolines. In comparison to related oxygen-containing substrates, the cycloaddition step of the catalytic cycle is shown to be slower, but the cycloreversion is found to be more facile.

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Naturally Occurring Isoflavonoids (1855–1981)

Cited by 49 publications

References 525 publications

The Absorption and Fluorescence of Isoflavones and the Effect of Shift Reagents

The Absorption and Fluorescence of Isoflavones and the Effect of Shift Reagents

Laboratory evaluation of aqueous leaf extract of Tephrosia vogelii against larvae of Aedes albopictus (Diptera: Culicidae) and non-target aquatic organisms

Synthesis of 1,2-Dihydroquinolines via Hydrazine-Catalysed Ring-Closing Carbonyl-Olefin Metathesis

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