Synthesis of pyrimidinophanes containing nitrogen atoms in polymethylene bridges

The reactions of 1,3-bis(-bromobutyl- or -pentyl)-6-methyluracil with 1,3-bis(-ethylaminobutyl- or -pentyl)-6-methyluracil afforded pyrimidinophanes containing N atoms in bridging polymethylene chains. Individual geometric isomers of pyrimidinophanes were isolated. The structure of one of these isomers was established by X-ray diffraction analysis. Quaternization of the bridging N atoms with o-nitrobenzyl bromide gave rise to water-soluble pyrimidinophanes.     

Synthesis,IR Spectra,and Steric Structure of Macrocycles Derived from Pyrimidine Compounds

A new macrocycle including pyrimidine fragments, 12,23,36-trimethyl-24,40-dioxo-15,33-dithia-2,9,13,22,26,35,38,39-octaazatetracyclo[32.3.1.110,14.122,26]tetraconta-1(38),10(39),11,13,23,34,36-heptaene, was synthesized. According to the data of IR and UV spectroscopy and HF/6-31G** quantum-chemical calculations, macrocyclic compounds of this series in crystal exist in the amino form, one NH group of which is likely to be involved in intramolecular hydrogen bond, and the other, in intermolacular hydrogen bond. The strength of the latter depends on the macroring size. In solution, the above structures are supplemented by conformers containing both intramolecularly H-bonded and free amino groups, predominantly with trans structure of the HÄNÄCÍN fragment. The imino form of the aminopyrimidine moieties is hardly probable.     

Condensation of <Emphasis Type="Italic">p</Emphasis>-Dimethylaminocinnamaldehyde with Aniline and Substituted Anilines in Micellar Media

Optimal conditions were found for the reactions of aniline and its hydroxy-, carboxy-, methyl-, and nitro-substituted derivatives with p-dimethylaminocinnamaldehyde in the presence of sodium dodecyl sulfate micelles in the pH range 1–6. A correlation was revealed between the optimal pH value pK _a of aromatic amines. The reaction in the model system aniline-p-dimethylaminocinnamaldehyde-sodium dodecyl sulfate in micelles formed by anionic surfactants is accelerated more than 1000-fold due to increased concentration of the reactive species in sodium dodecyl sulfate micelles.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 2, 2005, pp. 288–294.Original Russian Text Copyright © 2005 by Doronin, Chernova, Gusakova.     

Darzens synthesis of 2,2-dichloro-3-(2-furyl)-3-hydroxypropionic acid derivatives

Esters and amides of 2,2-dichloro-3-(2-furyl)-3-hydroxypropionic acid were prepared by the reaction of furfural with dichloroacetic acid derivatives under the conditions of the Darzens condensation. The structures of the reaction products were confirmed by their¹H NMR and IR spectra and chemical transformations.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1444–1448, August, 1994.     

Vibrational spectra and conformational isomerism of calixarene building blocks: 2-benzylphenol

The conformations and vibrational spectra of 2-benzylphenol have been analysed within the framework of scaled quantum mechanics. It is shown that the solid-state conformation of the 2-benzylphenol molecule corresponds to one of four potential energy minima predicted by non-empirical quantum chemical calculations for the isolated molecule. In the molten state and in diluted CCl4 solutions of the title compound this conformer coexists with another two spectroscopically detected conformations. The presence of several conformers gives rise to the observation of the corresponding number of vsCH2 and vasCH2 bands in the IR spectra, thus providing experimental evidence of the conformational sensitivity of the vCH2 frequencies. It is shown that vCH2 wavenumbers of different kinds of molecules, containing diphenylmethane fragments, are determined by the dihedral angles between the planes of the aromatic rings and the plane of the connecting methylene bridges, except for the case of short intramolecular contacts with the participation of the methylene protons.     

Synthesis, Cardiovascular Activity, and Electrochemical Oxidation of Nitriles of 5-Ethoxycarbonyl-2-methylthio-1,4-dihydropyridine-3-carboxylic Acid

Nitriles of 4-aryl-5-ethoxycarbonyl-2-methylthio-1,4-dihydropyridine-3-carboxylic acid have been obtained by the methylation of 1,4-dihydropyridine-2-thiolates; of 1,4-dihydropyridine-2(3H)-thiones in the presence of a stoichiometric amount of piperidine, and of a mixture of 1,4,5,6-tetrahydro- and 1,4-dihydropyridine-2-thiolates with methyl iodide. One-pot multicomponent synthesis has also been used in the condensation of ethyl 2-arylmethyleneacetoacetate, 2-cyanothioacetamide, piperidine, and methyl iodide; of ethyl acetoacetate, 3-aryl-2-cyanothioacrylamide, piperidine, and methyl iodide; and of ethyl acetoacetate, an aromatic aldehyde, 2-cyanothioacetamide, piperidine, and methyl iodide. The latter, a five-component method, takes place rapidly and under mild conditions, it is efficient (yields of 75-96%, economy of time, labour, and resources) and green (there is no need to synthesize lachrymators, such as 3-aryl-2-cyanothioacrylamides).The cardiovascular activity and the electrochemical oxidation of the synthesized 2-methylthio-1,4-dihydropyridines have been investigated. A comparative analysis has been carried out of the ability towards electrochemical oxidation as a function of the electronic properties of the substituent at position 4 of the heterocycle.     

Enthalpies of formation of organic free radicals of alcohol and ether derivatives

Numerical values of the enthalpies of formation of oxygen-containing organic radicals of alcohol and ether derivatives (Δ_f H°) were analyzed. For seven out of 25 compounds the corresponding Δ_f H° values were determined more accurately. For 35 radicals, the Δ_f H° values were determined for the first time based on the published values of bond dissociation energies in molecules and on the corresponding enthalpies of their formation. Based on the analysis of the Δ_f H° values for 60 radicals studied, a structure—property (enthalpy of formation) correlation was established, described in the framework of the group additivity scheme. The parameters for calculations of Δ_f H° values for the title radicals were recommended.     

Synthesis and Electrochemical Oxidation of Nitriles of 4-Aryl-2-carbamoylmethylthio-5-ethoxycarbonyl-1,4-dihydropyridine-3-carboxylic Acids

Nitriles of 4-aryl-2-carbamoylmethylthio-5-ethoxycarbonyl-6-hydroxy-1,4,5,6-tetrahydropyridine-3-carboxylic acids were obtained by the alkylation of 1,4,5,6-tetrahydropyridine-2-thiolate with iodoacetamide or by a three-component synthesis by condensing 2-arylmethylene-1,3-dicarbonyl compounds with 2-cyanothioacetamide in the presence of piperidine with subsequent reaction with iodoacetamide. Nitriles of 4-aryl-2-carbamoylmethylthio-5-ethoxycarbonyl-1,4-dihydropyridine-3-carboxylic acids were obtained by the dehydration of 6-hydroxy-1,4,5,6-tetrahydropyridines or with a one-reactor three-component system from 2-cyano-3-(4-methoxyphenyl)thioacrylamide, 1,3-dicarbonyl compounds, and iodoacetamide. The electrochemical oxidation of the synthesized nitriles was investigated and it was established that derivatives of 1,4,5,6-tetrahydropyridine as a rule are oxidized readily to the corresponding 1,4-dihydropyridines. A comparative analysis has been carried out of the ability of hydrogenated pyridines to be oxidized electrochemically depending on the electron-withdrawing properties of the substituents in the heterocycle.