CRYSTAL STRUCTURE AND HIRSHFELD SURFACE ANALYSIS OF 7-((6-HYDROXY-2,5,5,8A-TETRAMETHYL-1,4,4A,5,6,7,8,8A-OCTAHYDRONAPHTHALEN-1-YL)METHOXY)-2H-CHROMEN-2-ONE ISOLATED FROM FERULA PERSICA: A NEW ENANTIOMORPH AT 100 K

UDC 548.73:541.12

Abstract

From the underground part of Ferula persica, collected during the fruiting phase, an alcoholic extract was obtained, which, after removal of the solvent, was chromatographed on a column with neutral aluminium oxide (II degree of activity) and eluted with hexane, benzene, and their mixtures in a gradient of increasing polarity. As a result, 7-((6-Hydroxy-2,5,5,8a-tetramethyl-1,4,4a,5,6,7,8,8a-octahydronaphthalen-1-yl)methoxy)-2H-chromen-2-one (conferol – m.p. 137–138 °C), was isolated. For the confirmation of structure, we used X-Ray, NMR ¹H, ¹³C NMR, DEPT, COSY, HSQC, and HMBC methods. We note, that the crystal structure of the title compound, [systematic name; 7-((6-Hydroxy-2,5,5,8a-tetramethyl-1,4,4a,5,6,7,8,8a-octahydronaphthalen-1-yl)methoxy)-2H-chromen-2-one], C₂₄H₃₀O₄, has been reported previously at room temperature. The crystal structure was determined at higher precision at 100 K as a new enantiomorph. The title compound consists of two trans-fused cyclohexane rings, attached to the chromen-2-one moiety through an oxymethylene bridge. Cyclohexane rings adopt half-chair and chair conformations, respectively. The title compound is a new enantiomorph of the one reported. In the crystal, the molecules are joined by C-H···O hydrogen bonds along the c-axis, forming layers parallel to the (010) plane, while molecules are linked by O-H···O hydrogen bonds, which generate R22(6) motifs along the a-axis. The C-H···π and van der Waals interactions between these layers stabilize and maintain the structure. The Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H···H (58.3%), O···H/H···O (21.8%) and C···H/H···C (19.7%) contacts.