NMR spectra of pyrimidines

The chemical shifts of the protons in the even positions of the pyrimidine ring in 2- and 4-substituted pyrimidines in dimethyl sulfoxide solutions were determined. The correlation equations that link the relative chemical shifts (with allowance for corrections for the magnetic anisotropy of the substituents and the ring) with the F and R substituent constants were calculated. The ratios obtained were analyzed by comparison with the corresponding correlation equations for monosubstituted benzenes. The reasons for the significant increase in the transmission of the conjugation effects of the substituents to the even positions of the pyrimidine ring as compared with the meta positions of the benzene ring and the appreciable weakening of the conductivity of their inductive effects when the heteroring nitrogen atom is situated between a resonating proton and the substituent are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 673–677, May, 1978.     

Substituted propanes: V. The vibrational spectra,dipole moments and conformations of 1,2-dichloro-, 1-chloro-2-bromo- and 1,2-dibromopropane

The infrared and Raman spectra of 1,2-dichloro-, 1-chloro-2-bromo- and 1,2-dibromopropane were recorded as liquids, in polar and non-polar solvents and in the crystalline state at low temperatures. The infrared spectrum of a high pressure crystal of 1,2-dibromopropane was recorded at ambient temperature. Dipole measurements were carried out in CCl₄ and C₆H₆solutions.Each of the 1,2-dihalopropanes existed as a mixture of three conformers in the liquid state, the one with the halogens in the anti position was in large abundance. Spectral and dipole measurements revealed a comparatively larger concentration of the two polar gauche conformers in polar solvents. All the compounds crystallized in the anti form. The C-halogen stretching vibrations have been interpreted in detail. Vibrational analyses of the anti conformers have been carried out and a tentative assignment of the majority of the gauche bands has been proposed.     

Synthesis of heterocyclic compounds on the basis of carboxylic acid arylamides

The exchange and cyclization of phenyliminooxalyl chloride with ammonium thiocyanate, sodium azide, aniline, amidoximes, and diphenylthiourea, and with 2-aminopyridine, 2-aminobenzothiazole, and 2-amino- and 2-mercaptobenzimidazole were studied. The cyclization products are derivatives of thiazolidine, imidazo[1,2-a]pyridine, imidazo[2,1-b]benzothiazole, imidazo[1,2-a]benzimidazole, and thiazolo[3,2-a]benzimidazole. A trimer of 1-phenyltetrazole-5-carboxylic acid was obtained when an attempt was made to convert its azide to the corresponding isocyanate.See [1] for communication II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 471–474, April, 1971.