4-(2-Nitrobenzyl)-3-phenyl-3,4-dihydro-2H-1,4-benzoxazin-2-ol

Abstract

The title compound, C21H18N2O4, crystallizes with two independent molecules (A and B) in the asymmetric unit. In both molecules the oxazine ring has an envelope conformation with the hydroxyl-substituted C atom as the flap. The nitrobenzyl ring and the phenyl ring are almost normal to the mean plane of the benzooxazine ring system with dihdral angles of 85.72(15) and 82.69(15)°, respectively, in molecule A, and 85.79(15) and 87.72(15)°, respectively, in molecule B. The main difference in the conformation of the two molecules concerns the dihedral angle between the nitrobenzyl ring and the phenyl ring, viz. 79.67(18) in molecule A and 71.13(18)° in molecule B. In the crystal, the A and B molecules are linked by an O - H⋯O hydrogen bond. These units are then linked via C - H⋯O hydrogen bonds, forming sheets lying parallel to (010). Further C - H⋯O hydrogen bonds link the sheets to form a three-dimensional network. There are also O - H⋯π and C - H⋯π interactions present, reinforcing the three-dimensional structure.