Stereochemistry of hydroximic acid derivatives. Crystal and molecular structure of N-phenyl-2,6-dichlorobenzamide oxime

Abstract

The crystal and molecular structure of the title compound has been solved by direct methods from three-dimensional X-ray diffraction data and refined by least squares to R 0.042. Crystals are monoclinic, space group P2₁/c, with Z= 4 in a cell of dimensions: a= 12.489(4), b= 8.175(3), c= 13.266(4)Å, β= 102.73(3)°. The molecule occurs in the Z-configuration about the C:N bond (OH cis to NHPh) and in the s-trans-conformation about the C–N and N–O bonds, this stereochemistry being identical to that assigned to the prevailing form observed in solution. Short non-bonded distances are compatible with intramolecular NH ⋯ O and intermolecular OH ⋯ N hydrogen bonds; the latter, in pairs, couple the molecules in centrosymmetric dimers. The observed stereochemistry is consistent with the concepts of attractive non-bonded orbital interactions between the hydroxy- and N-phenylamino-group.