Etude de l'équilibre dans les oxazolo[2,3-e], thiazolo[2,3-e] et isoxazolo[2,3-d]tétrazoles. II. Etude de l'effet de la température par dipolemetrie et résonance magnétique nucléaire
- 15 May 1977
- journal article
- Published by Canadian Science Publishing in Canadian Journal of Chemistry
- Vol. 55 (10) , 1728-1735
- https://doi.org/10.1139/v77-244
Abstract
The equilibrium constant in dioxane between azido and tétrazole isomers has been obtained for five heterocyclic azides (2-azido thiazoles, benzothiazole, benzoxazole, and 3-azido isoxazole) by proton nmr and dipole moment- studies. The last method involves a comparison between experimental and calculated (INDO, CNDO/2, CNDO/S) dipole moments. The CNDO/S method gives the best equilibrium constants and entropy factor (ΔS ∼ 50 J K−1 mol−1). A value of 114° for the C—N—N angle is found to account satisfactorily for certain properties (energy, dipole moment, photoelectron spectra) of aromatic azides. The heterocyclic azidoimines prefer the Z conformation.Keywords
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