2,2,7,7-Tetra-methyl-1,2,3,6,7,8-hexa-hydro-cinnolino[5,4,3-cde]cinnoline.

The asymmetric unit of the title compound, C(16)H(20)N(4), contains two half-mol-ecules, which are completed by crystallographic inversion symmetry. The pyridazine rings are conjugated and the cyclo-hexane rings adopt envelope conformations.

3-(4-Bromo-phen-yl)-3-(4-hydr-oxy-6-oxo-1,6-dihydro-pyrimidin-5-yl)-N-[(S)-1-phenyl-ethyl]propanamide.

In the mol-ecule of the title compound, C(21)H(20)BrN(3)O(3), the pyrimidine ring is oriented at dihedral angles of 80.87 (3) and 15.99 (3)°, respectively, to the pyrimidine and bromo-phenyl rings. The dihedral angle between the two benzene rings is 88.37 (3)°. In the crystal structure, inter-molecular N-H⋯O and O-H⋯N hydrogen bonds link the mol-ecules. A π-π contact between pyrimidine and phenyl rings [centroid-centroid distance = 3.776 (3) Å] may further stabilize the structure. The methine H and the methyl C and H atoms are disordered over two positions and were refined with occupancies of 0.522 (13) and 0.478 (13).

7,14-Bis(4-bromo-phen-yl)-2,11,11-trimethyl-1,4,10,12-tetra-oxa-dispiro-[4.2.5.2]penta-decane-9,13-dione.

In the mol-ecule of the title compound, C(26)H(26)Br(2)O(6), the cyclo-hexane ring is in a chair conformation, while the five-membered and 1,3-dioxane rings both adopt envelope conformations. The dihedral angle between the benzene rings is 77.21 (3)°. In the crystal structure, weak inter-molecular C-H⋯O inter-actions link the mol-ecules into centrosymmetric dimers, forming R(2) (2)(14) ring motifs. One of the Br atoms, the methyl C and H atoms, and the C atom bonded to the methyl group of the five-membered ring are disordered over two positions. The Br atoms were refined with occupancies of 0.51 (4) and 0.49 (4), while the C and H atoms were refined with occupancies of 0.320 (18) and 0.680 (18).