Crystal structure of racemic (R/S,E)-2-(4-hy-droxy-phen-yl)-4-(2-phenyl-hydrazin-1-yl-idene)chromane-5,7-diol ethanol monosolvate.

The crystal structure of racemic (R/S,E)-2-(4-hy-droxy-phen-yl)-4-(2-phenyl-hydrazin-1-yl-idene)chromane-5,7-diol ethanol monosolvate, C(21)H(18)N(2)O(4)·C(2)H(6)O, in a centrosymmetric lattice is reported. The two racemates occupy the same position in the asymmetric unit - a disordered mixed enanti-omeric structure. Hydrogen bonds of the type O-H⋯C(π) in addition to typical C-H⋯O, O-H⋯O and O-H⋯N are identified. A positional disorder is seen in the solvent mol-ecule (ethanol) as well. The phenyl-hydrazone group is nearly coplanar with the chromane ring system [dihedral angle = 15.5†(1)°], while the the 4-hy-droxy-phenyl ring is perpendicular [dihedral angle = 87.2†(1)°] to the chromane. The pyran ring has an envelope pucker [Q = 0.363†(3)†à , θ = 57.6†(3)°; and for the enanti-omer: Q = 0.364†(3)†à , θ = 127.4†(4)°].