Acta Cryst. (2007). E63, o3948  [ doi:10.1107/S1600536807042201 ]

Isocedrelone

S. S. Devi, R. Malathi, S. S. Rajan, V. P. Santhanakrishnan and S. Narasimhan

Abstract: The title compound (systematic name: 17-furan-3-yl-6,15-dihydroxy-4,4,8,10,14-pentamethyl-8,9,10,11,12,14,15,16-octahydro-4H-cyclopenta[a]phenanthrene-3,7-dione), C₂₆H₃₀O₅, is a semi-synthetic derivative of cedrelone, a tetranortriterpenoid isolated from Toona ciliata. Both cedrelone and the title compound show similar antifeedant activity against third instar larvae of Spodoptera litura. The modification of the D ring of the parent compound has altered the conformation of ring C; however, the orientation of the furan ring as well as the conformations of other rings remain the same. The three fused six-membered rings adopt a boat, a half-chair and a chair conformation and the five-membered rings D and E adopt envelope and planar conformations, respectively. A macrocyclic ring motif, R₇⁶(40), S(5) and S(7), generated by C-HO and O-HO hydrogen bonds, stabilizes the molecules in the crystal structure.

Online 1 September 2007

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