Azomethines Based on Pyridoxal-Derived Aromatic Aldehydes

The reaction of pyridoxal with 2,4-dihydroxybenzaldehyde in a hydrochloric acid solution gave 1-(5-formyl-2,4-dihydroxyphenyl)-7-hydroxy-6-methyl-1,3-dihydrofuro[3,4-c]pyridin-5-ium chloride. Treatment of the latter with sodium hydride in ethanol afforded a free aldehyde in 85% yield. A series of azomethines and imidazolidines was obtained by reacting the obtained aldehyde with various amines and diamines.     

2<Emphasis Type="Italic">H</Emphasis>-Benzimidazole <Emphasis Type="Italic">N</Emphasis>-oxides: synthesis,chemical properties,and biological activity

The review presents and summarizes comprehensive data starting from 2006 on the synthesis of mono- and di-N-oxides of 2H-benzimidazoles and their chemical properties. Especial attention was paid to the chemical transformations of 2H-benzimidazole 1,3-dioxides upon heating to give 3H-2,1,4-benzoxadiazine 4-oxides and 2H-benzimidazole mono-N-oxides. The biological activity of compounds was covered.     

Synthesis of new nucleoside analogs containing amino bisphosphonic groups

Adenosine derivatives containing a 2,2-bis(diethoxyphosphoryl)ethyl or 2,2-diphosphonoethyl group on the amino nitrogen atom were synthesized for the first time by reaction of 5′-chloro-5′-deoxy- and 5′-hydroxy-2′,3′-isopropylideneadenosine with tetraethyl ethene-1,1-diylbis(phosphonate) or tetrakis(trimethylsilyl) ethene-1,1-diylbis(phosphonate).     

Synthesis and some properties of tetrakis-3,5-di-<Emphasis Type="Italic">tert</Emphasis>-butyl-4-hydroxybenzylated calix[4]resorcinols

A method for the synthesis of new calix[4]resorcinols tetra-3,5-di-tert-butyl-4-hydroxybenzyl derivatives is developed. Their interaction with methyldichlorophosphonate, dimethyldichlorosilane in the presence of a base leads to formation of organophosphorus-organosilicon cavitands. Acetylation of hydroxybenzylated calix[4]resorcinols with acetic anhydride leads to products of either incomplete or full acetylation depending on experimental conditions.     

Isatin acylhydrazones with sterically hindered phenolic fragments: synthesis and structures

Isatin acylhydrazones with sterically hindered phenolic fragments were obtained. Their structures were determined using 1D and 2D 1H and 13C NMR spectroscopy and X-ray diffraction. The products synthesized by condensation of isatin and 1-(3,5-di- tert-butyl-4-hydroxybenzyl)-l H-indole-2,3-dione with 3-(3,5-di- tert-butyl-4-hydroxyphenyl)propiono-hydrazide exist as E- and Z-isomers about the C=N bond. E— Z isomerization takes place in boiling ethanol. The E-isomer of the condensation product from isatin and 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionohydrazide was structurally characterized using X-ray diffraction: this isomer is a cis-conformer about the amide group and has a E-configuration about the N—N bond. According to data on the concentration dependence of the signals for the NH protons in the 1H NMR spectra, the acylhydrazones obtained are stabilized in solution by intra-and intermolecular hydrogen bonding.     

Synthesis of 2-arylpyrrolidines by reaction of γ-ureidoacetals with benzene-1,3,5-triol

New 2,2′-(2,4,6-trihydroxybenzene-1,3-diyl)dipyrrolidine derivatives have been synthesized by reaction of benzene-1,3,5-triol (phloroglucinol) with γ-ureidoacetals in the presence of trifluoroacetic acid as catalyst.     

Phosphorylated Aminoacetal in the Synthesis of New Acyclic,Cyclic, and Heterocyclic Polyphenol Structures

New phosphorylated aminoacetal has been synthesized by the Kabachnik–Fields reaction; its reactivity has been studied in acid‐catalyzed condensation with linear polyphenols (2‐methylresorcinol, resorcinol, pyrogallol) and the Mannich reaction with macrocyclic polyphenol (calix[4]resorcinol). It has been determined for the first time that acid‐catalyzed reaction of phosphorus‐containing acetal with resorcinol and its derivatives in ethanol in the presence of hydrochloric acid gives new phosphorylated piperazines in addition to the compounds of diarylmethane series. Condensation of macrocyclic polyphenol (calix[4]resorcinol) with formaldehyde and N‐((dihexylphosphoryl)methyl)‐2, 2‐dimethoxyethylamine (the Mannich reaction) has resulted in novel tetrasubstituted calixarene containing aminophosphine oxide and acetal groups on the “upper rim” of molecule.     

Alkylated polyethyleneimine-cationic surfactant-calix[4]resorcinarene-chloroform catalytic system

The kinetics of phosphorylation of alkylated polyethyleneimine in chloroform in the presence of cationic surfactants with a cyclic or bicyclic head group and alkylated calix[4]resorcinarenes has been investigated by UV spectrophotometry. The catalytic activity of individual and mixed solutions of the amphiphilic admixtures depends on the structure of the constituents of the composition, on their concentrations in the solution, and on their relative amounts. In the presence of a calixarene, a decrease in the surfactant and polymer concentrations enhances the catalytic effect of the system.