Research Article: 3-Cyano-11-oxo-3,4-seco-12a-aza-C-homoolean-4(23)-en-28-oic acid methyl ester

Date Published: February 01, 2012

Publisher: International Union of Crystallography

Author(s): A. Froelich, B. Bednarczyk-Cwynar, A. K. Gzella.


The title compound, C31H48N2O3, is a Beckmann rearrangement product. The isopropenyl and meth­oxy­carbonyl groups have β-orientations, whereas the 2-cyano­ethyl group has an α-orientation. In the triterpenoid skeleton, the seven-membered lactam ring, as well as the three six-membered carbocyclic rings, have chair conformations. In the crystal, mol­ecules are linked via nonclassical C—H⋯O hydrogen bonds into layers parallel to the ab plane.

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For ring-puckering parameters, see: Cremer & Pople (1975 ▶). For a related structure, see: Froelich & Gzella (2010 ▶). For bond-length data, see: Allen et al. (1987 ▶). For related literature on the Beckmann rearrangement reaction, see: Bednarczyk-Cwynar (2006 ▶).