organic compounds
Open access
In the title molecule, C16H14N4O4, the quinazoline ring is substantially planar (r.m.s. deviation = 0.0129 Å) and forms a dihedral angle of 2.73 (8)° with the benzene ring. The conformation of the molecule is stabilized by an intramolecular C—HN hydrogen bond. In the crystal, molecules are linked into chains running parallel to the b axis by C—HO hydrogen bonds. In addition, π–π stacking is observed between dimethoxy-substituted and nitro-substituted benzene rings, with centroid–centroid distances in the range 3.6438 (10)–3.7148 (10) Å.
organic compounds
Open access
The title molecule, C10H10N4O2, is almost planar and adopts an E configuration of the azomethine [C=N = 1.298 (2) Å] double bond. The benzene ring is attached to an essentially planar (r.m.s. deviation = 0.0226 Å) amidine moiety (N=CN/Me2), the dihedral angle between the two mean planes being 18.42 (11)°. The cyano group lies in the plane of the benzene ring [the C and N atoms deviating by 0.030 (3) and 0.040 (3) Å, respectively], while the nitro group makes a dihedral angle 5.8 (3)° with the benzene ring. There are two distinct intermolecular hydrogen bonds, C—HO and C—HN, that stabilize the crystal structure; the former interactions result in centrosymmetric dimers about inversion centers resulting in ten-membered rings, while the later give rise to chains of molecules running parallel to the b axis.