CRYSTAL AND MOLECULAR-STRUCTURE OF AZADIRACHTIN-A

Azadirachtin-A isolated from the seed kernels of Azadirachta indica A. Juss has been crystallized and the structure has been studied through X-ray diffraction techniques Mr = 720.72, tetragonal, P41 a = b = 20. 960(5), c = 9.415(4) angstrom, V = 4136(2) angstrom3, Z = 4, d(cal) = 1.157 gm c-3, lambda(CuKalpha) = 1.5418 angstrom, mu = 0.74 mm-1 (F000 ) = 1528, T = 295-degrees-K final R = 0.071 for 2139 reflections. I > 3 sigma (I). The rotation of the two bulky groups about the C8-C14 bon d is - 162.4(7)-degrees in Azadirachtin-A and is different from that i n detigloyl-22,23-dihydroazadirachtin. Also there is no hydrogen bond that connects the two halves as in detigloyl-22,23-dihydroazadirachtin . The intra and inter- molecular hydrogen bondings are also quite diff erent in these two structures.