N,N'-Di­hydroxy­benzene-1,2:4,5-tetra­carboximide dihydrate

In the title compound, C₁₀H₄N₂O₆·2H₂O, the organic mol­ecule has crystallographically imposed inversion symmetry. The atoms of the three fused rings of the mol­ecule are coplanar within 0.0246 (8) Å, while the two hy­droxy O atoms are displaced from the mean plane of the mol­ecule by 0.127 (1) Å. In the crystal, infinite near-planar layers of close-packed mol­ecules are formed by hydrogen bonding between water O-H donor groups and carbonyl O-atom acceptors, and by weak inter­actions between C-H donor groups and water O-atom acceptors. The layers are parallel to the {102} family of planes. The stacked planes are held together by hydrogen bonding between N-OH donor groups and water O-atom acceptors.

Dipentyl 2,6-di­amino­benzo[1,2-b:4,5-b′]di­furan-3,7-di­carboxyl­ate

The title compound, C₂₂H₂₈N₂O₆, crystallizes with one half-mol­ecule in the independent unit, the mol­ecule being located on an inversion centre. The penthyl groups are in the all-trans conformation and an almost planar conformation of the whole mol­ecule is observed [maximum deviation from the least-squares plane through all non-H atoms is 0.0229 (17) Å for an N atom]. The amino groups are involved in intra- and inter­molecular hydrogen bonds. Intra­molecular hydrogen bonding involving the amino group and ester carbonyl helps to lock the syn conformation of the ester with respect to the amino group. In the crystal, N—H...O hydrogen bonding involving the amino group and the furan and ester carbonyl O atoms self-assembles the mol­ecules into a two-dimensional hydrogen-bonded network parallel to (010) that displays inter­digital packing sustained by alk­yl–alkyl inter­actions.