Crystal structure of 1beta-hydroxy-beta-homopipitzolone (9-hydroxy-2,6,9-trimethyltricyclo[6,3,1,0(1,6)]dodeca-5,10,11,12-tetraone).

C15H18O5 is orthorhombic, P2(1)2(1)2(1). The unit-cell dimensions at 293 K are a = 6.526(3), b = 10.247(4), c = 21.008(13) A, V = 1404.8(12) A3, Dx = 1.316 g/cm3, and Z = 4. The R value is 0.044 for 1288 observed reflections. The A, B and C rings adopt chair, twist, and half-chair conformations. The absolute configuration is inferred from the C6 stereochemistry of (+)-cedrol. The crystal structure is stabilized by an O-H...O hydrogen bond and van der Waals forces.