Crystal, molecular structure and Hirshheld surface analysis of 5-hydroxy-3,6,7,8-tetramethoxyflavone

Abstract

The title compound (systematic name: 5-hydroxy-3,6,7,8-tetramethoxy-2-phenyl-4H-chromen-4-one), C19H18O7, is a flavone that was isolated from a butanol extract of the herb Scutellaria nepetoides M. Pop. The flavone molecule is almost planar, with a dihedral angle between the planes of the benzopyran-4-one group and the attached phenyl ring of 6.4 (4)°. The 5-hydroxy group forms a strong intramolecular hydrogen bond with the carbonyl group, resulting in a six-membered hydrogen-bonded ring. The crystal structure has triclinic (P\overline{1}) symmetry. In the crystal, the molecules are linked by C—H...O hydrogen bonds into a two dimensional network parallel to the ab plane. The Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H...H (53.9%) and H...O/O...H (20.9%) interactions.

Use of 3-Deoxy-D-arabino-heptulosonic acid 7-phosphate Synthase (DAHP Synthase) to Enhance the Heterologous Biosynthesis of Diosmetin and Chrysoeriol in an Engineered Strain of Streptomyces albidoflavus

“…A difference between flavones and flavanones is the spatial configuration of their chemical structures. Flavones present a planar structure [ 37 ], while flavanones present a chair conformational structure [ 38 ]. According to this, we hypothesize that the enzyme M444_29925 may introduce a methyl group in a different position in a flavanone structure, such as eriodictyol, instead of the 4′ position, as observed in flavones.…”