Synthesis of 4-ethoxyflavylium salts and flavones

4-Ethoxybenzopyrylium salts, which are converted to the corresponding flavones in quantitative yields by refluxing with water, were synthesized by condensation of o-hydroxyacetophenones with aromatic aldehydes in the presence of ethyl orthoformate and 70% perchloric acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 187–190, February, 1977.     

Phenylpropanoid glycosides of Teucrium polium

Together with poliumoside we have isolated for the first time from golden germander verbascoside and a new phenylpropanoid glycoside (teupolioside) for which the structure of 2-(3,4-dihydroxyphenyl)ethyl O-β-D-galactopyranosyl-(1→2)-O-α-L-rhamnopyranosyl-(1→3)-4-O-caffeoyl-β-D-glucopyranoside is proposed. A mixture of poliumoside and teupolioside revealed a moderate antibacterial activity. A. L. Mnadzhoyan Institute of Fine Organic Chemistry, Armenian Academy of Sciences, Erevan. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 630–634, September–October, 1991.     

Rearrangement-Cleavage of Ammonium Salts Containing a 3-Methyl-2-naphthylmethyl Group

The example of the rearrangement-cleavage under the action of 25% aqueous potassium hydroxide at 90-92°C of ammonium salts containing both 3-methyl-2-naphthylmethyl and 2-bromoethyl, allyl, methallyl, 2-bromoallyl, 3-phenylallyl, 2-propynyl, or 3-phenylphenyl-2-propynyl groups was used to show that the reaction always involves the aromatic ring of the 3-methyl-2-naphthylmethyl group. Along with rearrangement-cleavage, nucleophilic substitution of the 2-naphthylmethyl group takes place.     

Structure of Silica Formed by Carbonation of Alkaline Silicate Solution

The structure of silica formed by carbonation of alkaline silicate solution was studied by adsorption, electron microscopy, and sedimentation analysis.     

The Measure of the Set of Zeros of the Sum of a Nondegenerate Sine Series with Monotone Coefficients in the Closed Interval [0, π]

Mathematical Notes - Nonzero sine series with monotone coefficients tending to zero are considered. It is shown that the measure of the set of those zeros of such a series which belong to [0,...     

Determination of Phenolic Aldehydes in Cognacs and Wines by Capillary Electrophoresis: New Cognac Quality Markers

A new method for the determination of vanillin, syringaldehyde, coniferaldehyde, and sinapaldehyde in wines and cognacs by high-performance capillary electrophoresis was developed. It simultaneously determines phenolic aldehydes within a few minutes using a diode-array detector. The method requires no sample preparation. The use of a borate buffer solution with pH 9.3 as a mobile phase increases the UV absorption intensity of these compounds and thus lowers the detection limit. The method is characterized by high reproducibility with dispersion coefficients from 4.47 to 6.89% for all of the analytes. The calibration graphs were linear in the concentration range of 0.30 to 57.0 mg/L. The age of cognacs can be determined by this method with an accuracy of 98.68% and a relative standard deviation of 10%.