Andirobin from X. moluccensis.

THE TITLE COMPOUND (SYSTEMATIC NAME: methyl 2-{(1R,2R)-2-[(1aS,4S,4aS,8aS)-4-(furan-3-yl)-4a-methyl-8-methyl-ene-2-oxoocta-hydro-oxireno[2,3-d]isochromen-7-yl]-2,6,6-trimethyl-5-oxocyclo-hex-3-en-1-yl}acetate), C(27)H(32)O(7), was isolated from X. moluccensis seeds from Thailand. The conformations of the six-membered rings are distorted half-chair, chair and half-chair for the isolated cyclo-hexane, fused cyclo-hexane and lactone rings, respectively. In addition, the lactone ring bears in an equatorial orientation an essentially planar furan ring (r.m.s. deviation = 0.004 Å), which forms an angle of 63.87 (13)° with the mean plane defined by the ten atoms of the two fused six-membered rings (r.m.s. deviation = 0.213 Å). The absolute configuration was fixed on the basis of literature data.