Crystal structure of 7β-hydroxyroyleanone isolated fromTaxodium ascendens(B.)

Abstract

The title compound, C 20 H 28 O 4 [systematic name: (4bS,8aS,10S)-3,10-dihydroxy-2-isopropyl-4b,8,8-trimethyl-4b,5,6,7,8,8a,9,10-octahydrophenanthrene-1,4-dione], is an abietane-type diterpene, which was isolated from Taxodium ascendens (B.). The compound crystallizes in the chiral space group P2 1 , but it was not possible to determine the absolute structure of the molecule in the crystal by resonant scattering. The molecular structure is stabilized by two intramolecular O-HÁ Á ÁO hydrogen bonds, enclosing S(5) and S(6) ring motifs. In the crystal, molecules are linked by O-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds, forming chains along the [010] direction. The crystal structure of the 10R stereoisomer of the title compound, isolated from the roots of Premna obtusifolia (Verbenaceae), has been reported. It crystallized in the chiral space group P2 1 2 1 2 1 , and the absolute structure was determined as (4bS,8aS,10R), by resonant scattering using Cu K radiation [Razak et al. (2010). Acta Cryst. E66, o1566-o1567].