The structure of N-(azol-N-yl) formamides: a crystallographic and dynamic NMR spectroscopy study
作者:Loreto Salazar、Modesta Espada、Dionisia Sanz、Rosa Ma Claramunt、José Elguero、Santiago García-Granda、Ma Rosario Díaz、Fermín Gómez-Beltrán
DOI:10.1039/p29930000377
日期:——
The molecular structures of N-(pyrazol-1-yl)formamide 1 [C4H5N3O, orthorhombic, space group P2(1)2(1)2(1), a = 5.269(8), b = 8.039(8), c = 12.79(2), Z = 4] and N-(indazol-1-yl)formamide 5 [C8H7N3O, monoclinic, space group P2(1)/c, a = 9.065(2), b = 11.089(7), c = 8.463(7), Z = 4] have been solved by X-ray crystallography. Regarding the amide bond, both compounds exist in the Z configuration, a configuration which also prevails in solution for all theN-H azolyl formamides whilst the N-substituted derivatives prefer the E configuration. The rotation barriers about the amide bond are similar although a little lower than those of N-phenylformamide and N-methyl-N-phenylformamide, a fact that may be related to the electronic properties of the N-azolyl substituent.