Etude par RMN du proton d'hétérocycles voisins de l'oxazaphospholane-1,3,2. I—La phényl-3 oxo-2 oxathiazolidine-1,3,2

A complete analysis of the ¹H NMR spectrum of the title compound is used for the conformational assignment of the molecule in the C-4—C-5 region. The position of protons is related to the position of the S?O bond with the help of a europium complex Eu(fod)₃. The results obtained are consistent with those found for similar compounds with or without a phosphorus atom.     

Préparation de dithiényl-2-éthène-1,2, de dithiényl-2-pyrimidine-2,4 et de dithiényl-2-pyridazine-3,6

The condensation of 2-thienylmagnesium bromide with (Z)-1,2-dichloroethene 2,4-dichloropyrimidne, 3,6-dichloropyridazine and with a transition metal catalyst is described. The yields of these reactions are very good; 1,2-bis(2-thienyl)ethene and two new heterocyclic compounds 2,4-bis92-thientyl)pyrimidine and 3,6-bis(2-thienyl)pyridazine were obtained in one step from commercial products.     

Structure du méthyl-3 phénylamino-4 phényl-5 triazole-1,2,4

The crystal structure or 3-methyl-4-phenylamino-5-phenyl-1,2,4-triazole has been determined by X-ray diffraction. It allows one to choose between the two reaction mechanisms which can be taken into account for the reaction of hydrazine upon N-acylated hydrezonates.     

Structure électronique, spectre ultraviolet et solvatochromie du tétracyano-1,1,3,3 aza-2 propénure de tetramethylammonium

CNDO/S calculations are performed for the [(CN)₂-C-N-C-(CN)₂]⁻ anion. The observed and theoretical ultraviolet spectra are in perfect agreement. A theoretical analysis of the electronic structure and solvation energy of ground and excited singlet states confirms the almost total lack of sensitivity of the electronic spectrum to solvent effects.