Pleiades Publishing Ltd

A one-pot procedure has been developed for the synthesis of 2,7-diaryl(hetaryl)-4,9-dimethylperhydro- 2,3a,5a,7,8a,10a-hexaazapyrenes by cyclocondensation of aren(hetaren)amines with formaldehyde and 2,6-dimethyl-1,4,5,8-tetraazadecalin in the presence of YbCl3 · 6 H2O as catalyst.

Application of ethanol to the synthesis of 1,3-dioxolanes by the condensation of carbonyl compounds with vicinal diols results in a high yield of the reaction product and considerably reduces the duration of the process. It is assumed that the effect of the ethanol is caused by the adduct formation with carbonyl compounds (hemiacetals) which behave as active intermediates of the condensation. A cyclic ketal of acetone with glycerol obtained with the help of ethanol was used as a basis component in the synthesis of a series of ketals substituting diol or carbonyl components by transketalyzation mechanism proceeding without water liberation.

The effect of the substituent nature on the rate and activation parameters of transesterification of a series of 4-nitrophenyl benzoates with benzenethiol in dimethylformamide in the presence of potassium carbonate was studied by the competing reaction method. In all cases, change of the Gibbs energy of activation is determined mainly by variation of the enthalpy of activation. 4-Nitrophenyl benzoates having electron-withdrawing substituents in the benzoyl fragment were found to fit an isokinetic relation with an isokinetic temperature β of 318 K. Enthalpy-entropy compensation effect was observed in the reactions with all the examined 4-nitrophenyl benzoates. The relation between the reactivity and polarizability of nucleophilic center in S-and O-nucleophiles is discussed.

New water-soluble acetyl derivatives of β-cyclodextrin were synthesized, and their complexing ability toward phenolphthalein was studied.

Treatment of 3-methylcyclohexanone with ethyl formate in the presence of sodium methoxide afforded sodium (2-methyl-6-oxocyclohexylidene)methanolate which reacted with aminopyrazoles, aminotriazole, and aminotetrazole to produce fused quinazoline derivatives; its reactions with cyanothioacetamide, cyanoacetamide, and cyanoacetohydrazide gave tetrahydroquinoline-3-carbonitrile derivatives. The reactions of 8-methyl-2-sulfanyl-5,6,7,8-tetrahydroquinoline-3-carbonitrile with alkylating agents led to the formation of thieno[2,3-b]quinoline derivatives. DFT computational studies of the synthesized compounds were carried out using B3LYP/6−311+G** and HF/6−311+G** approximations. The calculated HOMO and LUMO energies showed that charge transfer occurs in their molecules.

Dissolution of sulfur in the system hydrazine hydrate-alkali leads to strong activation of hydrazine, so that the latter readily reacts at room temperature with aldehydes of the aromatic and thiophene series to give the corresponding aldehyde azines in high yield. The mechanism of activating effect of sulfur is discussed.