Crystal structure of ent-7 alpha,18-diacetoxykaur-16-ene (epicandicandioldiacetate)

The title compound (C24H36O4) crystallizes in the orthorhombic space group P2(1)2(1)2(1) with a=6.250(1) Angstrom, b=13.676(1) Angstrom, c=25.419(2) A ngstrom, V=2172.7(1) Angstrom (3), Z=4, D-x=1.19 g.cm(-3). The structure wa s solved by direct methods and refined by full-matrix least-squares method (R=0.076). The title molecule is an entkaurene diterpene containing two ace toxy groups at positions C7 and C18, The ring junction A-B is in trans, whi le B-C is in cis. The rings A and B have chair conformations, while ring C has a twist conformation but the conformation of ring D is nearer to an env elope.