Yu. N. Surov

Intramolecular interactions in series of oxazole, oxadiazole, and triazole derivatives

A comparison of the PMR spectra of 5-phenyl-2-methyl derivatives of oxazole, 1,3,4-oxadiazole, and 1, 3, 4-triazole with the spectrum of toluene leads to the conclusion that the electron-acceptor character of the heterocycles drops off in the order oxadiazole >oxazole>triazole. The conduction of electronic effects of the substituents by the oxazole ring is at the level of benzene; the 1, 3, 4-oxadiazole ring accomplishes the transmission somewhat better, and the 1,3,4-triazole ring more weakly, than in the case of benzene. The formation of H-complexes with a 1∶1 composition in a system consisting of the azole, phenol, and carbon tetrachloride was investigated by means of IR spectroscopy. The relative n-donor strength, of the heterocycles decreases in the series triazole >oxazole> oxadiazole. The effectiveness of transmission of electronic influence of the substituents in the phenyl radical on the pyridine nitrogen atom, which is the center of complexation, decreases in the series oxazole >oxadiazole>triazole.

Reaction of 3-Benzoyl-2,3-dibromopropionic Acid with Substituted ortho-Phenylenediamines

Abstract3-Benzoyl-2,3-dibromopropionic acid reacts with 4-substituted o-phenylenediamines to give 3-aryl-2-carboxymethylene-1,2-dihydroquinoxalines.

Transmission of the electronic effects of substituents by the thiophene ring

The shifts in the frequencies of the stretching vibrations of the hydroxyl group of phenol and pentachlorophenol that arise during the formation of hydrogen bonds with a number of substituted acetophenones and 2-acetylthiophenes, 2-acetylfuran, and 2-acetylselenophene and the frequencies of the stretching vibrations of the carbonyl group of the latter were subjected to a correlation analysis (with the Hammett, Brown, Taft, Yukawa-Tsuno, and Swain-Lupton equations), and it was shown that the thiophene ring in the investigated molecules in both the static state and during the formation of H complexes transmits the conjugation effects better than the benzene ring.

Synthesis and Study of Aromatic Derivatives of 5,6-Dihydro-4-pteridinol

The reaction of 4-hydroxy-5,6-diamino- and 2,5,6-triaminopyrimidines with substituted α-bromoacetophenones gives aryl derivatives of 5,6-dihydro-4-pteridinols. The course of these reaction is discussed and the physicochemical characteristics of these products were studied.

Synthesis and spectral properties of 2-methyl-5-aryl-1,3,4-oxadiazoles

By heterocyclization of 1-acyl-2-aroylhydrazines under the influence of strong dehydrating substances, a series of 2-methyl-5-aryl-1,3,4-oxadiazoles has been synthesized and their UV, IR, and PMR spectra have been investigated. Through analysis of data on the influence of substituents on the position of the maximum in the electronic absorption spectrum, together with calculated data, it has been shown that the long-wave band of 2-methyl-5-phenyl-1,3,4-oxadiazole is due to an S0−S1 transition of the π−π* type and that it is a charge transfer band for transfer from the phenyl radical to the oxadiazole ring; the 1,3,4-oxadiazole ring as a substituent has an electron-acceptor character.

Investigation of azlactones and azlactams by IR spectroscopy

The IR spectra of a number of azlactones and their structural analogs, viz., azlactams, in solutions in carbon tetrachloride and in chloroform and in the solid phase were obtained. The character of the interaction of the carbonyl group of the heteroring with substituents with different electronic natures has a substantial effect on the frequencies of the stretching vibrations of the carbonyl group and the azomethine and ethylene bonds. The carbonyl frequencies were subjected to correlation analysis, and high conductivity of the electronic effects of substituents in the 2-phenyl-4-arylideneoxazol-5-one series was ascertained.

Synthesis and proton-acceptor capacities of 5-aryl-2-acetylthiophenes and 1-(5-aryl-2-thienyl)-1propenones

A number of 5-aryl-2-acetylthiophenes and 1-(5-aryl-2-thienyl)-3-phenyl-1-propenones were synthesized, and it was shown by means of their IR spectra that the 1-propenones are trans isomers with respect to the orientation of the substituents attached to the double bond and have an s-cis conformation. According to the data from the IR spectra of the H complexes of the investigated compounds with phenol, 5-aryl-2-acetylthiophenes have higher proton-acceptor capacities than acetophenones, 2-acetylthiophenes, and 4-acetyldiphenyl; a similar picture is also noted in a number of 1-propenones and 3-propenones. The transmission factors (π′) obtained by Hammett correlation of the ΔνOh values for 1,4-phenylene, 2,5-thienylene, and vinylene groupings are identical and are equal to 0.8. It is shown on the basis of a correlation with respect to an equation of the Yukawa-Zuno type that the thiophene ring transmits polar conjugation better than the benzene ring.

Structures of the products of formylation of 1,3,5-triphenyl- and 1,5 -diphenyl-3-stryl-2-pyrazolines

It was established by means of IR and PMR spectra and chemical transformations that the products of the Vilsmeier formylation of 1,3,5-triphenyl- and 1,5-diphenyl-3-styryl-2-pyrazolines are the corresponding 1-(p-formylphenyl)-2-pyrazolines. The frequencies of the stretching vibrations of the carbonyl group and the chemical shift of the aldehyde proton of these compounds indicate considerable conjugation of the p electrons of the N1 atom of the pyrazoline ring with the aldehyde group.

Synthesis of hydroxyl containing N-imides of 4-substituted naphthalic acid

A convenient, one-step method for synthesis of the N-(3-hydroxypropyl)imide of 4-(3′-hydroxypropyl)-aminonaphtalic acid is proposed. It has been found that ethylene glycol monoethyl ether can be successfully used to replace solvents previously used for these reactions.

Association constants of substituted 2-acetylthiophenes with phenol

The association constants (Kass) of a number of substituted 2-acetylthiophenes and 3-acetylthiophene with phenol in tetrachloroethylene solutions at 25, 50, and 80° were determined by IR spectroscopy. It is shown that acetylthiophenes are stronger proton acceptors than the corresponding acetophenones. The thermodynamic characteristics (ΔH and ΔS) of the association were calculated, and the presence of a compensation effect was established. It is shown on the basis of correlation of the Kass values by means of the Brown, Yukawa-Tsuno, and Swain-Lupton equations that the thiophene ring is a better transmitter of the effect of substituents than the benzene ring because of the increased conductivity of the conjugation effect.