Crystal structure of 3,4a,7,7,10a-pentamethyl-3-vinyldodecahydro-1H-benzo[f]chromen-9-ol isolated from Sideritis perfoliata

Abstract

The asymmetric unit of the title compound, C20H34O2, contains two crystallographically independent molecules (1 and 2) with similar conformations. In both molecules, the cyclohexane rings adopt a chair conformation, while the oxane rings are also puckered. In the crystal, O—H...O hydrogen bonds connect adjacent molecules, forming C(6) helical chains located around a 21 screw axis and running along the crystallographic a axis. The packing of these chains is governed only by van der Waals interactions. Semi-empirical PM3 quantum chemical calculations are in a satisfactory agreement with the structural results of the X-ray structure analysis. The absolute structure was indeterminate in the present experiment.

Keywords

• crystal structure
• cyclohexane ring
• semi-empirical PM3 method
• HOMO
• LUMO