4-[6-(4-Formyl-2-methoxy­phen­oxy)hex­yloxy]-3-methoxy­benzaldehyde

The title compound, C₂₂H₂₆O₆, was prepared by the reaction of 4-hydr­oxy-3-methoxy­benzaldehyde and 1,6-dibromo­hexane, displays mol­ecular symmetry C_i, and has a crystallographic centre of inversion located at the mid-point of the C-C bond of the aliphatic chain. The zigzag aliphatic chain is coplanar with the aromatic rings of the vanillin groups.

4-[2-(4-Formyl-2-methoxy­phen­oxy)eth­oxy]-3-methoxy­benzaldehyde

The title compound, C₁₈H₁₈O₆, was prepared by the reaction of 4-hydr­oxy-3-methoxy­benzaldehyde and 1,2-dibromo­ethane. There are one and a half mol­ecules in the asymmetric unit; one has C₁ mol­ecular symmetry and the other C_i, with the centre of inversion at the mid-point of the aliphatic C-C bond. The ethyl­enedi­oxy groups are coplanar with the aromatic systems of the vanillin groups.

3,3′-Dihydr­oxy-4,4′-(propane-1,3-diyldi­oxy)dibenzaldehyde

The title compound, C₁₉H₂₀O₆, is composed of two individual vanillin subunits bonded to a central chain of C atoms. The mol­ecule lies on a twofold rotation axis. The two aromatic rings are approximately perpendicular to each other and both make a dihedral angle of 53.36 (4)° with the backbone chain. A weak C—H...π inter­action consolidates the crystal packing.