X-ray Diffraction Study of 2,4a,4b,5,6,7,8,9,9a,10-Decahydro-7, 10-Dihydroxy-2, 4a-epoxy-8-methylene-7, 9a-Methanobenz |a| Azu-lene-1-Carboxylic Acid Ethyl Ester (2α, 4aα, 4bβ, 7β, 9aα, 10β)

C19H22O5, monoclinic, P21/a, a = 16.298(6), b = 8.359(2), c = 13.183(3) A, β = 112.32(2)°; V = 1661.4(8)A3, Dx = 1.32 g cm−3 for Z = 4. The structure has been solved by direct methods (MULTAN 80) and refined to a final R value of 0.051 for 2017 observed reflections. The stereochemistry of the title compound is as depicted for one enantiomer in 1; the configuration of the asymmetric carbons can be specified as C(3)R, C(6)R, C(8)S, C(9)R, C(10)R, and C(13)S. The five-membered B ring is a half-chair with pseudodiad axis through C(10). The six-membered ring of the bicyclo|3.2.1| octane substructure adopts a distorted chair conformation.