The title compound, C(11)H(14)N(2)O(4), crystallizes with two independent but essentially identical mol-ecules in the asymmetric unit. Each mol-ecule adopts a trans configuration with respect to the C=N bond. Mol-ecules are linked into a one-dimensional network by inter- and intra-molecular N-H⋯O and C-H⋯O hydrogen bonds.

The title compound, C(14)H(20)O(2), crystallizes with homochiral chains of mol-ecules hydrogen bonded together along the b axis. Adjacent chains in the ab plane contain mol-ecules of the same chirality, leading to a chiral segregation of the mol-ecules into layers.

The title compound, C(12)H(14)O(6), features a roughly planar mol-ecule (r.m.s. deviation for all non-H atoms = 0.287 Å). In the crystal, the mol-ecules are held together by C-H⋯O hydrogen bonds.

The mol-ecule of the title compound, C(14)H(22)O(4), is centrosymmetric. In the crystal, the mol-ecules are linked through O-H⋯O hydrogen bonds into a three-dimensional network.

The title 2-aza-bicyclo-[2.2.2]octa-2,5-diene derivative, C(14)H(18)N(4)O, crystallized out with two independent mol-ecules with similar conformations in the asymmetric unit. In each mol-ecule, the three six-membered rings adopt boat conformations. The mol-ecules exist in the enamine form. In the crystal, mol-ecules are linked by N-H⋯O and N-H⋯N hydrogen bonds into a two-dimensional network par...

The asymmetric unit of the title compound, C(14)H(11)ClN(2)O(2)·H(2)O, contains a Schiff base mol-ecule and a water mol-ecule of crystallization. The dihedral angle between the two aromatic rings is 27.3 (4)°. In the crystal structure, mol-ecules are linked into a two-dimensional network parallel to the bc plane by inter-molecular O-H⋯O and N-H⋯O hydrogen bonds involving the water mol-ecules.

The asymmetric unit of the title compound, C(14)H(10)Br(2)N(6)O, contains two crystallographically independent mol-ecules. The pyrazole ring of one mol-ecule makes dihedral angles of 22.0 (3) and 3.5 (3)° with the pyrimidine and benzene rings, respectively; the corresponding values in the other mol-ecule are 9.2 (3) and 2.1 (3)°, respectively. The mol-ecules are linked by N-H⋯O, C-H⋯N and C-H⋯B...

The asymmetric unit of the title compound, C(16)H(14)O(2), contains one half-mol-ecule, located on a twofold rotation axis. In the mol-ecule, the two benzene rings form a dihedral angle of 72.28 (2)°.