Reactions of dialkyl phosphonates and phosphonates with bis(benzylideneimino)toluene

Dialkyl phosphonates bind to the C=N bond of bis(benzylideneimino)toluene, with formation of dialkyl (benzylideneimino)benzylaminobenzyl phosphonates. The complicated character of IR spectra of these compounds is connected with the possibility of formation of dimeric cyclic associates and intramolecular hydrogen bonding. Phosphinic acid reacts with bis(benzylidenimino)toluene in a 2: 1 ratio to affordN,N-benzylidenebis(-amino-benzytphosphonic) acid.Translated fromIzvestiya Akademii Nouk. Seriya Khimicheskaya, No. 5, pp. 1303–1305, May, 1996.     

Synthesis,Structure, and Electrochemical Characteristics of 4-Aryl-2-carbamoylmethylthio-5-ethoxycarbonyl-1,4-dihydropyridine-3-carboxylic Acid Nitriles

We have obtained 4-aryl-2-carbamoylmethylthio-5-ethoxycarbonyl-1,4-dihydropyridine-3-carboxylic acid nitriles by S-alkylation of the corresponding 2-thioxo-1,2,3,4-tetrahydropyridine-3-carboxylic acid nitrile by iodoacetamide or one-pot multicomponent synthesis methods: condensation of 2-arylidene-acetoacetic acid ethyl ester, 2-cyanothioacetamide, piperidine, and iodoacetamide; acetoacetic acid ethyl ester, 3-aryl-2-cyanothioacrylamide, piperidine, and iodoacetamide; acetoacetic acid ethyl ester, an aromatic aldehyde, 2-cyanothioacetamide, piperidine, and iodoacetamide. We have carried out a comparative analysis of the capability of 2-alkylthio-4-aryl-5-ethoxycarbonyl-1,4-dihydropyridine-3-carboxylic acid nitriles for electrochemical oxidation as a function of the electronic properties of the aryl substituent in the 4 position of the heterocycle and the 2-alkylthio substituent. X-ray diffraction data indicate the existence of a hydrogen bond between the C=O of the 2-carbamoylmethylthio substituent and the NH of the hydrogenated heterocycle, which explains the more facile oxidation of the studied compounds compared with 2-methylthio-substituted 1,4-dihydropyridines.Dedicated to Academician V. Minkin to show our appreciation for his contribution to organic chemistry and his wonderful humanity, remembering his collaboration with his colleagues from Riga.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 416–428, March, 2005.     

Reaction of ethylN,N-(p-methoxybenzal)-p-aminobenzoate with dialkyl phosphonates

Abstact Interaction of ethylN,N-(p-methoxybenzal)-p-aminobenzoate with dialkyl phosphonates results in dialkyl (N-p-ethoxycarbonylphenylamino)-p-methoxybenzal phosphonates. In the resulting compounds hydrogen bonds are observed by IR spectroscopy.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1301–1303, May, 1996.     

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.     

Novel macrocyclic uracil derivatives: Structure in solid and solution

Isomeric pyrimidinophanes containing uracil moieties and nitrogen atoms in bridges have been synthesized and characterized by a variety of methods both in solid and in solution. Unambiguous assignment of mutual arrangement of C(4)_pyrO groups at different pyrimidine rings in isomers is made by X-ray diffraction. In solutions the arrangement of C(4)_pyrO groups of the isomeric pyrimidinophanes results in different dipole moments. Based on dipole moments simulations mutual orientation of uracil units in isomers is analysed. UV-data are discussed in terms of hypo- or hyperchromic effect.     

Dipole moments and molecular spectra of certain derivatives of dibenzalacetone

Conclusions From the spectral data it may be assumed that di-p-chlorodibenzalacetone exists in solution as a mixture of s-cis,s-cis- and s-cis, s-trans-conformations, possessing a trans-configuration of both ethylenic bonds, which does not contradict the data of the dipole moments.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1485–1489, July, 1969.     

Determination of number and composition of platinum(IV) aqua complexes in solutions using mathematical statistics methods

Conclusions The formation of monoaqua compounds in acidified solutions of Pt(IV) hydroxy complexes was confirmed, and their composition was determined by comparing the curves that express the degree of forming the complexes as a function of the solution pH with the results of a statistical processing of the titration curves.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1859–1861, August, 1976.     

Stationary combustion modes with allowance for heat losses

An attempt is made to investigate the number of possible stationary combustion modes in a continuous-flow semi-infinite pipe with allowance for heat losses through the walls. Cases of a zero-order reaction in the reaction mixture or similarity of the concentration and temperature fields are considered. The equations are averaged with respect to the transverse coordinate . Within the framework of these approximations it is found that the number of stationary combustion modes is determined by the roots _n of some function. The roots _2k correspond only to trivial unstable solutions. The roots _2k–1 correspond to modes possible within broad regions of variation of the parameters characterizing the temperature of the mixture, the mixture feed rate, and the rate of heat removal. These regions intersect, forming zones where several stationary modes coexist. In these zones, apart from monotonic solutions there may also be solutions that initially make several oscillations. It is shown that the latter are obviously unstable and, in the last analysis, lead to one of the monotonic modes. The common case of not more than three roots is examined in detail.If the heat release function can change sign, then a similar picture is also observed in the absence of heat losses through the walls (the roots _2k–1 and _2k may change roles). In this case it is no longer necessary to average the equations with respect to , since there will not be any corresponding derivatives.