Redetermined structure of oxaline: absolute configuration using Cu Kα radiation.
In the title compound, C(24)H(25)N(5)O(4), 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 intra-molecular N-H⋯O hydrogen bond supports the near coplanarity of the two C(3)N(2)-five-membered rings [dihedral angle = 5.64 (10)°]. In the crystal, mol-ecules are linked by N-H⋯N hydrogen bonds, forming a C(8) chain propagating in [001]. The chains are connected by C-H⋯O inter-actions, 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.
Key Laboratory of Marine Drugs of the Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, 266003 Qingdao,  People's Republic of China.
Peng
P
Qu
Zhi-Yong
ZY
Wu
Wei-Ming
WM
Zhu