E. Bunuel et al., A NEW CONFORMATIONALLY RESTRICTED ASPARTIC-ACID ANALOG WITH A CYCLOHEXANONE SKELETON, Acta crystallographica. Section C, Crystal structure communications, 52, 1996, pp. 2641-2644
In the compound (1R, do-2-methoxycarbonyl-5-oxocyclohexane-1-carboxyli
c acid, C16H17NO6, the cyclohexanone ring adopts a distorted chair con
formation. The carboxylic acid and the methyl ester groups occupy the
axial positions, while the benzamido group is equatorial. The values d
etermined for the torsion angles about the N-C-alpha(phi) and C-alpha-
CO(psi) bonds correspond to a semi-extended conformation for the amino
acid residue. The crystal structure is stabilized by two intermolecul
ar hydrogen bonds (O-H ... O and N-H ... O) involving the carboxylic a
cid, the benzamido and the methyl eater groups.