Ethyl 4-(5-bromo-2-hy-droxy-phen-yl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexa-hydro-quinoline-3-carboxyl-ate.

In the title compound, C21H24BrNO4, the dihedral angle between the heterocyclic ring and the pendant aromatic ring is 80.20 (13)°. The hexahydroquinone [i.e. the one with the C=O group] ring adopts a sofa conformation. An intra-molecular O-H⋯O hydrogen bond generates an S(6) ring motif. The ethyl group is disordered over two sets of sites with a refined site occupancy ratio of 0.633 (10):0.366 (10). In the crystal, mol-ecules are linked by N-H⋯O inter-actions, forming chains parallel to [101]. There are no significant C-H⋯π or π-π inter-actions in the crystal structure.

Ethyl 2,7,7-trimethyl-5-oxo-4-phenyl-1,4,5,6,7,8-hexa-hydro-quinoline-3-carboxyl-ate.

In the title compound, C(21)H(25)NO(3), the hydro-pyridine ring that constitutes a part of the hexa-hydro-quinoline fused-ring system adopts a sofa conformation; the methine C atom deviates from the least-squares plane defined by the remaining five non-H atoms (r.m.s. deviation = 0.088 Å) by 0.454 (3) Å. The phenyl ring is aligned at 85.5 (1)° with respect to this mean plane. In the crystal, adjacent molecules are linked via an N-H⋯O hydrogen bond, involving the amino group and the carbonyl O atom of the fused-ring system, forming chains running along [100]. The ethyl group is disordered over two positions in a 0.609 (6):0.391 (6) ratio.

9-(2-Hy-droxy-4,4-dimethyl-6-oxocyclo-hex-1-en-1-yl)-3,3-dimethyl-2,3,4,9-tetra-hydro-1H-xanthen-1-one.

The cyclo-hexene ring that constitutes a part of the tetra-hydroxanthene fused-ring system of the title compound, C(23)H(26)O(4), adopts a flattened half-chair conformation that approximates an envelope conformation (in which the methyl-ene C atom bearing the two methyl substituents represents the flap) as five of the six atoms lie approximately on a plane (r.m.s. deviation = 0.020 Å). The mean plane of the cyclo-hexene ring with the hy-droxy substituent is approximately perpendicular to the mean plane of the tetra-hydroxanthene system. In the crystal, adjacent mol-ecules are linked by O-H⋯O(carbon-yl) hydrogen bonds into a chain running along the b axis.

1-(9-Methyl-11-sulfanyl-idene-8-oxa-10,12-diaza-tricyclo-[7.3.1.0]trideca-2,4,6-trien-13-yl)ethanone.

The six-membered oxacyclo-hexene ring of the title compound, C(13)H(14)N(2)O(2)S, is fused with the benzene ring and the quarternary C atom lies above the plane of the benzene ring by 0.229 (8) Å, whereas the methine C atom (which bears the acetyl substituent) lies below this plane by 0.595 (8) Å. The oxacyclo-hexene ring is also fused with the sofa-shaped 2,6-diaza-cyclo-hexa-none ring. The methine C atom that belongs to both six-membered rings lies above the mean plane of the other five atoms (r.m.s. deviation = 0.077 Å) by 0.759 (5) Å. In the crystal, N-H⋯S hydrogen bonds link adjacent mol-ecules into a linear chain.

1-(2-Oxo-3,4-dihydro-2H-1,3-benzoxazin-4-yl)urea monohydrate.

The organic molecule in the title hydrate, C(9)H(9)N(3)O(3)·H(2)O, was obtained by the condenstation of salicylic aldehyde with urea in acetonitrile. The oxazine ring adopts a slightly distorted sofa conformation, with the N atom deviating from the plane passing through the other atoms of the ring by 0.267 (2) Å. The crystal structure displays inter-molecular N-H⋯O and O-H⋯O hydrogen bonding.