Crystal Structure of Methyl-2-cyano-3,11-dioxo-urs-1,12-dien-24-oate

抄録

The title compound, methyl 2-cyano-3,11-dioxo-urs-1,12-dien-24-oate (C₃₂H₄₃N₁O₄), crystallizes in the orthorhombic space group P2₁2₁2₁ with the following unit-cell parameters: a = 7.8862(2), b = 17.6554(3), c = 20.0326(5)Å, Z = 4. The crystal structure was solved by direct methods, and refined by full-matrix least-squares procedures to a final R-value of 0.0365 for 4164 observed reflections. The dihedral angle between the ester moiety and ring A is 83.9(1)°. Rings B, D and E exist in chair conformations, while rings A and C adopt sofa conformations. The ring junctions A/B and B/C are trans fused, while ring junctions C/D and D/E are quasi-trans and cis, respectively. The methyl carbons located at various positions are significantly deviated above and below the plane of the molecule. The crystal structure is stabilized by intra and intermolecular C-H…O hydrogen bonds.