5-(3,4-Dimeth­oxy­benzyl­idene)-1,3-dimethyl-1,3-diazinane-2,4,6-trione

In the title compound, C₁₅H₁₆N₂O₅, the dihedral angle between 1,3-diazinane and benzene rings is only 4.27 (1)°. The essentially planar mol­ecular structure is characterized by a short intra­molecular C—H...O separation and by an exceptionally large bond angle of 138.25 (14)° at the bridging methine C atom. The meth­oxy groups deviate somewhat from the plane of the benzene ring, with C—C—O—C torsion angles of −15.6 (1) and 9.17 (6)°. In the crystal, mol­ecules form centrosymmetric dimers via donor–acceptor π–π inter­actions, with a centroid–centroid distance of 3.401 (1) Å.

4-(2-Bromo­phen­yl)-2-phenyl­pyrano[3,2-c]chromen-5(4H)-one

In the title compound, C₂₄H₁₅BrO₃, the pyran­ochromenone ring is essentially planar, while the 2-bromo­phenyl group is almost perpendicular to it [85.58 (6)°]. In the crystal, inversion dimers linked by pairs of weak C—H...π bonds occur; there is also a short inter­atomic contact found between the Br and carbonyl O atoms [3.016 (1) Å].

2,5-Dihexyl­thio­phene 1,1-dioxide

In the title mol­ecule, C₁₆H₂₈O₂S, the two n-hexyl groups are in all-trans conformations. Their C atoms are situated close to the plane of the thio­phene ring with a maximum deviation of 0.718 (6) Å for one of the terminal methyl groups. In the crystal, a short C—H...O contact is observed between thio­phene 1,1-dioxide groups.