(S)-2,2′-Dihy­droxy-N,N′-(6-hy­droxy­hexane-1,5-di­yl)dibenzamide

In the title compound, C₂₀H₂₄N₂O₅, the dihedral angle between the two roughly planar salicyl­amide fragments [r.m.s. deviations = 0.043 (2) and 0.149 (2) Å] is 25.50 (5)°. The mol­ecular conformation is stabilized by intra­molecular O—H...O hydrogen bonds involving phenol –OH groups and amide O atoms. Inter­molecular hy­droxy­meth­yl–amide O—H...O and amine–hy­droxy­methyl N—H...O hydrogen bonds form infinite chains along the b axis. These chains are further inter­linked by amine–amide N—H...O and phenol–phenol O—H...O inter­actions, thus giving layers parallel to (001).