Crystal structures of three newly synthesized flavanone hydrazones.

The crystal structures of racemic mixtures of three new flavanone-hydrazones in the centrosymmetric space group ( P ), are reported. The structures of (±, E )- N '-[5,7-dihy-droxy-2-(4-hy-droxy-phen-yl)chroman-4-yl-idene]-2-(naphthalen-1-yl)acetohydrazide ethyl acetate monosolvate, C 27 H 22 N 2 O 5 ·C 4 H 8 O 2 , and of (±, E )- N '-[5,7-dihy-droxy-2-(4-hy-droxy-phen-yl)chroman-4-yl-idene]-4-hy-droxy-benzo-hydra-zide ethanol monosolvate, C 22 H 18 N 2 O 6 ·C 2 H 5 OH, both exhibit an intra-molecular O-H⋯N and multiple inter-molecular O-H⋯O and C-H⋯O-type hydro-gen bonds. The third structure, that of (±, E )- N '-(6-methoxy-2-phenyl-chroman-4-yl-idene)-2-(naphthalen-1-yl-oxy)acetohydrazide, C 28 H 24 N 2 O 4 , has only one inter-molecular N-H⋯O-type hydrogen bond. In each of the three cases, the crystal packings are stabilized by π-π stacking inter-actions between various aromatic components of symmetry-related mol-ecules. The chiral carbon atom of the substituted chromane ring system in each case is puckered away from rest of the ring system.