[2-(2-Nitrophenyl)oxiran-1-yl](aryl(methyl))ketones in the synthesis of 3-hydroxyquinolin-4(1H)-ones and 2-arylquinolines

Russian Chemical Bulletin - The applicability of [2-(2-nitrophenyl)oxiran-1-yl](aryl(methyl))ketones in the synthesis of 3-hydroxyquinolin-4-ones and 2-arylquinolines was studied.     

Effect of structure of tetramethyl sulfonated calix[4]resorcinarene aggregates on paraquat redox reactions

The influence of amphiphilic tetramethyl sulfonated calix[4]resorcinarenes with different lengths of hydrophobic tails (R = CH₃, C₅H₁₁) and trihydroxymethyl amide macrocycle on the behavior of a paraquat in the electrochemical redox process in aqueous solutions is studied. It is revealed that the aggregation of molecules with pentyl substituents makes it possible to partially or completely block the reduction of the paraquat and to resume the redox process depending on the concentration and ratio of components.     

Guest controlled aggregation of amphiphilic sulfonatomethylated calix[4]resorcinarenes in aqueous solutions

Supramolecular nanoaggregates formed through the association of amphiphilic sulfonatomethylated calix[4]resorcinarenes with different substituents on the lower rim (methyl, pentyl, heptyl) and number of aromatic, aliphatic, and cationic guests differing in their shapes and sizes were investigated in aqueous solution by various NMR techniques ((1)H, 2D NOESY, FT-PGSE). It was shown that slight variations of the alkyl chain length on the lower rim of calixresorcinarenes dramatically change their aggregation behavior. Unlike the other calixresorcinarenes studied, the "head-to-tail" packing mode is observed for calixresorcinarene with pentyl moieties on the lower rim, which is unusual for amphiphilic calixarene aggregates. This calixresorcinarene demonstrates the stronger binding capacity toward the guest molecules due to their encapsulation into the capsule-like aggregate subunits. The guest-host complexation modifies the properties of both components, with the size of the resulted colloid particles being controlled by the guest nature.     

Binding of polar organic substrates by amphiphilic calixresorcin[4]arenes in the solution bulk and on the surface of anion-exchange resin

A comparative study is performed on the binding properties of free and immobilized water-soluble calixresorcin[4]arenes with respect to neutral organic molecules, one of which is capable of forming inclusion complexes, while the other possesses a fairly high potential of many-point hydrogen binding with the groups of the upper rim of macrocycle (parent substances of drugs Xymedon® and Dimephosphon®). It is revealed that macrocycle tetraanions present in aqueous solutions can be electrostatically immobilized on anion-exchange resin Amberlite IRA-900 Cl. The immobilization leads to changes in the binding mechanism of studied substrates due to the formation of calixresorcinarene aggregates on the surface of ion-exchange resin. The sorption of individual substrates and their mixtures is considered and models of the structure of immobilized aggregates of macrocycles and the mechanism of the binding of neutral guest molecules by the aggregates are proposed.     

Synthesis of new hydrazones based on tetrathiacalix[4]arene in the 1,3-<Emphasis Type="Italic">alternate</Emphasis> conformation

Reactions of 1,3-alternate stereoisomers of tetrathiacalix[4]arene and 4-tert-butyltetrathiacalix[4]-arene, functionalized by hydrazide groups, with benzaldehyde and pyridin-2-carbaldehyde gave new tetrathiacalix[ 4]arene tetrahydrazone derivatives as promising receptors for transition and toxic heavy metal ions.     

Supramolecular Systems Based on Novel Mono‐ and Dicationic Pyrimidinic Amphiphiles and Oligonucleotides: A Self‐Organization and Complexation Study

Novel mono‐ and dicationic pyrimidinic surfactants are synthesized and their aggregation behavior is studied by methods of tensiometry and nuclear magnetic resonance (NMR) self‐diffusion. To estimate their potentiality as gene delivery agents, the complexation with oligonucleotides (ONus) is explored by dynamic light scattering (DLS) and zeta‐potential titration methods and ethidium bromide exclusion experiments. Bola‐type pyrimidinic amphiphile (BPM) demonstrates rather a weak affinity to ONus. Although it induces mixed associations with ONus, only slight charge compensation changes occur at a large excess of bola, with no recharging reached. Similarly, the ethydium bromide exclusion study reveals a slow increase in the binding capacity toward an ONu with an increment in BPM concentration. The monocationic pyrimidinic surfactant (MPM) and its gemini analogue (GPM‐1) are ranked as intermediates in both their aggregative activity and complexing properties toward ONus. They both form mixed associates with ONus well below the critical micelle concentrations (cmcs) of 2 and 15 mM respectively. However, GPM‐1 has a much lower isoelectric point at the molar ratio surfactant/ONu r～1 compared to r～3 for MPM. This probably indicates a larger electrostatic contribution to the ONu complexation in the case of GPM‐1. The most hydrophobic pyrimidinic surfactant (GPM‐2), bearing three alkyl tails, demonstrates enhanced aggregative activity and binding capacity toward ONus as compared to former pyrimidinic surfactants. Due to effective aggregative (low cmc of 0.04 mM ) plus binding properties (fraction of bound ONu β=0.76 at r=2.5), GPM‐2 may be ranked as a promising agent for wider biological applications.     

New phosphorus-containing analog of calix[4]resorcinarene based on 2,6-dihydroxypyridine

Acid-catalyzed reaction of 2,6-dihydroxypyridine hydrochloride with diethyl 2,2-diethoxyethylphosphonate or 2-ethoxyvinylphosphonyl dichloride in aqueous ethanol furnished a tetramer, phosphorus-containing analog of calix[4]resorcinarene with pyridine fragments in the molecule. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 352–354, February, 2007.     

The rearrangement of 1H,1′H-spiro[quinoline-4,2′-quinoxaline]-2,3′ (3H,4′H)-diones – a new and efficient method for the synthesis of 4-(benzimidazol-2-yl)quinolin-2(1H)-ones

A new and highly efficient method for the synthesis of 4-(benzimidazol-2-yl)quinolin-2(1H)-ones via the rearrangement of spiroquinoxalinones in moderate-to-excellent yields has been developed. The rearrangement represents a facile approach to medicinally important biheterocyclic compounds. Compared to other methods, the present protocol has a number of advantages such as – cost-effectiveness, avoidance of difficult of access quinolin-2-one and benzimidazole derivatives as reaction partners, and easy accessibility of starting materials, making it a highly practical approach to access various 4-(benzimidazol-2-yl)quinolin-2(1H)-ones.     

Synthesis of 1,3-diketo derivatives of calix[4]arene with nonyl substituents at the lower rim as novel efficient sensibilizers of Tb<Superscript>3+</Superscript> luminescence

Novel bis- and tetra-1,3-diketo derivatives of calix[4]arene with nonyl substituents at the lower rim have been synthesized. Their conformational and tautomeric composition have been determined; spectral parameters and complex formation properties with Tb³⁺ have been studied. Substitution of two 1,3-diketo groups with bromine under going from tetra- to bis 1,3-diketone derivatives was resulted in twofold increase luminescence intensity in their terbium complexes. Lifetime of the excited state of the terbium luminescence of the corresponding complexes as well as lifetime of excited triplet level of the 1,3-diketonate ligands have been determined.     

Novel thermoresponsive water-soluble oligomers based on amphiphilic calixresorcinarenes

Novel water-soluble thermoresponsive oligomers TO1 and TO2 were obtained by reaction of amidoamine tetramethylcalixresorcinarenes (C1) and tetrapentylcalixresorcinarenes (C5) with ethylene glycol diglycidyl ether. The compounds were characterised by ¹H and FT-PGSE NMR, FTIR, static light scattering and elemental analysis. The thermoresponsive properties of oligomers were investigated by spectrophotometry, DLS, FT-PGSE NMR and TEM. The cloud points of oligomers (43 °C for TO1 (5 mg/ml) and 41 °C for TO2 (1.2 mg/ml), respectively) were determined. The influence of salts effect on TO2 cloud points was investigated. The binding of anti-inflammatory drug naproxen (Nap) at 20 °C by TO1 and TO2 and its partial release at cloud points of oligomers in aqueous solution are observed using fluorescence and FT-PGSE NMR methods. New example of creating of thermoresponsive macrocyclic systems on the basis of amidoamine calixresorcinarenes with possibility of substrate binding and release under the influence of termo-stimuli in an aqueous solution was shown.