3-(4-Bromo-phen-yl)quinazolin-4(3H)-one

2-Ethyl-3-[(R)-2-phenyl-butanamido]-quinazolin-4(3H)-one monohydrate

In the title compound, C20H21N3O2·H2O (EQR·H2O), the quinazoline ring system forms dihedral angles of 53.1 (1) and 85.6 (1)° with the phenyl ring and the amide link, respectively. In the crystal, O-H⋯O hydrogen bonds link two EQR and two water mol-ecules into a centrosymmetric R 4 (4)(18) ring motif. N-H⋯O hydrogen bonds further link these hydrogen-bonded fragments into columns extending in [010].

7-Chloro-6,8-dinitro-quinazolin-4(3H)-one acetic acid monosolvate

In the title compound, C₈H₃ClN₄O₅·C₂H₄O₂, both the nitro groups are close to perpendicular [dihedral angles = 67.62 (15) and 86.73 (12)°] to the almost planar quinazoline unit [r.m.s. deviation = 0.014Å]. In the crystal, both the quinazoline and acetic acid mol­ecules form inversion dimers linked by pairs of N—H⋯O and O—H⋯O hydrogen bonds, respectively. R₂²(8) loops arise in each case.