There are two independent mol-ecules in the the asymmetric unit of the title compound, C(11)H(14)N(2)O. The heterocyclic ring of the bicyclic system has a sofa conformation, with the C atom bearing the two methyl groups displaced by 0.541 (7) Å from the rest of the atoms of the ring [planar to within 0.064 (9) Å]. Mol-ecules are linked into centrosymmetric dimers via N-H⋯O hydrogen bonds.

In the title compound, [Zn(H(2)O)(6)](C(13)H(10)NO(4)S)(2), a distorted ZnO(6) octa-hedron results from the coordination by the six water mol-ecules. Only three of the water molecules are crystallographically unique, as the Zn atom lies on an inversion center. The Zn-O bond lengths are in the range 2.054 (4)-2.073 (4) Å. A network of hydrogen bonds helps to establish the crystal packing.

The mol-ecules of the title compound, C(15)H(16)N(2)O(4), are linked via N-H⋯O hydrogen bonds, forming undulating one-dimensional chains. Adjacent chains are linked by weak C-H⋯π inter-actions, forming a three-dimensional network.

There are two mol-ecules in the asymmetric unit mol-ecule of the title compound, C(8)H(10)ClN(3)O(2). Intra-molecular N-H⋯O hydrogen bonds stabilize the mol-ecular structure. There are no classical inter-molecular hydrogen bonds in the crystal structure.

The title mol-ecule, C(12)H(12)N(6)O(2), lies on a crystallographic inversion center with all non-H atoms essentially coplanar.

There are two mol-ecules in the asymmetric unit of the title compound, C(4)H(13)NO(2)SSi. In the crystal, mol-ecules are linked via inter-molecular N-H⋯O hydrogen bonds, forming chains along [001]. The crystal studied was an inversion twin, the refined ratio of twin domains being 0.61 (9):0.39 (9).

The two mol-ecules in the asymmetric unit of the title compound, C(9)H(6)ClNO(3), are nearly planar, with r.m.s. deviations of 0.034 and 0.037 Å. The crystal structure is stabilized by two weak inter-molecular N-H⋯O inter-actions.

The mol-ecule of the title compound, C(6)H(5)ClN(2)O(2), is close to being planar (rms deviation = 0.032 Å for all non-H atoms), with a maximum deviation of -0.107 (3) Å for an O atom. In the crystal structure, inter-molecular N-H⋯O and N-H⋯N inter-actions link the mol-ecules into a three-dimensional network.