Redetermined structure of oxaline: absolute configuration using Cu Kα radiation

Abstract

In the title compound, C24H25N5O4, the stereogenic C atom bonded to three N atoms and one C atom has an S configuration and its directly bonded neighbour has an R configuration. An intramolecular N—H...O hydrogen bond supports the near coplanarity of the two C3N2-five-membered rings [dihedral angle = 5.64 (10)°]. In the crystal, molecules are linked by N—H...N hydrogen bonds, forming a C(8) chain propagating in [001]. The chains are connected by C—H...O interactions, generating a three-dimensional network. The previous study [Nagel et al. (1974). Chem. Commun. pp. 1021–1022] did not establish the absolute structure and no atomic coordinates were published or deposited.