title: Azadirachtol, a tetranortriterpenoid from neem kernels.
abstract: The title compound, dimethyl (-)-(2aR,3R,4R,4aS,5R,7aS,8R,10S,10aR)-3,8,10-trihydroxy-4-[(2R,6R)-2-hydroxy-11-methyl-5,7,10-trioxatetracyclo[6.3.1.0(2,6)0(9,11)]dodec-3-en-9-yl]-4-methylperhydroisobenzofurano[5,4,3a-cd]isobenzofuran-5,10a-diacetate, C(28)H(36)O(13), which exhibits higher antifeedant activity than azadirachtin-A, a known potent antifeedant, was isolated from neem kernels. The asymmetric unit of the structure contains two independent molecules, which differ in the conformations of their functional groups and also in the conformations of some of the rings. The relative orientation between the decalin and furanyl moieties is similar to that observed in the majority of azadirachtin structures, but is different from that in azadirachtin-A. The two symmetry-independent molecules are linked into dimeric units by intermolecular O-H.O hydrogen bonds.
authors.affiliation: Department of Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India.
authors.forename: R
authors.initials: R
authors.lastname: Malathi
authors.forename: S S
authors.initials: SS
authors.lastname: Rajan
authors.forename: Geetha
authors.initials: G
authors.lastname: Gopalakrishnan
authors.forename: G
authors.initials: G
authors.lastname: Suresh
mesh_terms: D031601:Azadirachta / Q000196:embryology*; D003461:Crystallography; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure; D012639:Seeds / Q000737:chemistry*; D014315:Triterpenes / Q000737:chemistry*
chemical_list: D014315:Triterpenes; C472318:azadirachtol