CRYSTAL-STRUCTURE OF 14,ALPHA-HYDROXY,SANDAROCOPIMAR-7,15-DIENE-19-OIC ACID

C20H30O3, M(r) = 318.46, Monoclinic, P2(1), a = 12.232(2)angstrom, b = 11.491(2)angstrom, c = 14.160(3)angstrom, beta = 115.2-degrees (3), V = 1800.3(7)angstrom3, Z = 4, D(x) = 1.18 Mg m-3, lambda(CuKalpha) = 1 .5418angstrom, mu = 5.3 cm-1, F(000) = 696, T = 298 K. Final R = 0.044 for 2645 reflections with I > 2sigma. The two crystallographically in dependent molecules in the unit cell adopt essentially similar conform ations. The structure reveals a trans relationship between the hydroge n at C(9) and the methyl group at C(20). The stereochemistry at C(13) is S. Apart from van der Waals forces the structure is stabilized by h ydrogen bonds.