Robinetin

Eosin Flavonoids Morin Flavonol, fisetin, robinetin Quercetin Rutin condensation products of urea, formaldehyde and methanol [126], pesticide derivatives [127] sweetening agents [128, 129] anion-active and nonionogenic surface-active agents [130] steroids, pesticides [29,132, 133] pesticides [134—137] vanadium in various oxidation states [138] uracil derivatives [139]... 

Dipping solution I Dissolve SO mg N-bromosuccinimide in SO ml acetone [3]. Dippii solution II Dissolve SO mg robinetin in 70 ml ethanol [3]. 

It is assumed that the hydrogen bromide released on the oxidation of thiophosphoric acid insecticides with N-bromosuccinimide or bromine vapors forms intensely fluorescent salt-like derivatives with 3-hydroxyflavones — such as robinetin [1, 2, 4]. 

Note A range of pesticides can be detected on cellulose layers using 3-hydroxyflavones without prior bromination. Thus, the natural fluorescence of robinetin or fisetin, which is weak in a non-polar environment, is significantly enhanced by the presence of polar pesticides [2, 5, 7, 8],... 

Compounds 1 = 4-hydroxycoumarin 2 = umbelliferon 3 = 4-methyl-esculetin 4 = isopimpinellin 5 = esculin 6 = flavone 7 = a-naphtoflavone 8 = kaempferol 9 = quercetin 10 = isoquercitrin 11 = robinetin 12 = robinin 13 = myricetin 14 = luteolin 7-O-glucoside 15 = rutin 16 = hes-peretin 17 = hespiridin 18 = naringin 19 = pelargonin chloride 20 = polargonin chloride 21 = malvin chloride. 

The retention behaviour of flavonoids has also been extensively studied on silica stationary phases using heptane, benzene or dichloromethane as weaker components of the binary mobile phase and ethyl acetate and methyl ethyl ketone as modifier. Flavones (3-hydroxy, 5-hydroxy and 7-hydroxyflavone, tectochrysin, chrysin, apigenin, genkwanin, baicalein), flavonols (galangin, pilloin, kaempferol, rhamnetin, quercetin, robinetin,... 

Robinetin Rubraflavone A Rubraflavone C Rubraflavone D Saltillin Salvigenin Sanaganone Sanggenon J Sanggenon K Santin... 

Pentalhydroxyflavone (5-deoxymyricetin, robinetin) 7-Glucoside Alternanthera sessilis Amaranthaceae 447... 

Sahu, B.R. and Chakrabarty, A.A., A flavone glycoside, robinetin 7-glucoside from Alternanthera sessilis, Asian J. Chem., 5, 1148, 1994. 

Method 2 (silica gel layers). The silica gel chromatoplates are activated at 105 °C for 30 min before use. After cooling, the samples are applied at a distance of 2 cm from the bottom of the plate and then developed with an appropriate solvent system (for example, hexane-acetone (5 1) for organothiophosphorus compounds [165]). The plate is dried for 5 min at 105 °C and is placed while still hot in a chromatography chamber containing a small beaker of a 10% solution of bromine in carbon tetrachloride. After 10 sec the chromatoplate is removed, cooled and sprayed with a 0.05% solution of flsetin, robinetin or flavonol in ethanol. The plate is heated for 5 min at 105 °C in order to produce the fluorescence. The plates are then observed at a wavelength of 370 nm. 

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