CRYSTAL-STRUCTURES AND MOLECULAR-STRUCTURES OF UTILIN-B AND UTILIN-C TETRANORTRITERPENOIDS FROM BARK OF ENTANDROPHRAGMA-UTILE

The structures of utilin B and C (chemical formula: C38H50O14 and C33H 42O12) have been investigated in the solid state by X-ray diffraction methods. Utilin B crystallises in monoclinic system, space group P2(1) , with cell constants alpha = 9.868(3), b = 11.382(3), c = 16.816(3) A ngstrom, beta = 94.97(2)degrees. Utilin C crystallises in orthorhombic system, space group P2(1)2(1)2(1), with cell constants alpha = 10.942 (1), b = 12.803(1), c = 23.443(2) Angstrom. Both crystal structures we re solved by direct methods and refined by the full-matrix least-squar es method giving R = 0.059 (wR = 0.042) for Utilin B and R = 0.039 (wR = 0.037) for Utilin C. The molecular structures of both compounds as postulated from earlier spectral investigations, particularly with res pect to the positions of ester substituents, were fully confirmed.