Received 25 August 2009
The title compound [systematic name: (1R,4aS,10aR)-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydrophenanthrene-1-carboxylic acid], C20H28O2, has been isolated from disproportionated rosin which is obtained by isomerizing gum rosin with a Pd-C catalyst.. Two crystallographically independent molecules exist in the asymmetric unit. In each molecule, there are three six-membered rings, which adopt planar, half-chair and chair conformations. The two cyclohexane rings form a trans ring junction with the two methyl groups in axial positions. The crystal structure is stabilized by intermolecular O-HO hydrogen bonds.
For the synthesis and uses of dehydroabietic acid, see: Halbrook & Lawrence (1966); Jia et al. (2009); Piispanen et al. (2001); Rao et al. (2006); Rao, Song & He (2008); Rao, Song, He & Jia (2008); Sepulveda et al. (2005); Wada et al. (1985).
Data collection: CAD-4 Software (Enraf-Nonius, 1985); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: AT2868 ).
This work was supported by the National Natural Science Foundation of China (grant No. 30800871) and the Fundamental Research Foundation of the Central Commonwealth Institute of the Chinese Academy of Forestry (grant No. CAFYBB2008021),
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