title: (3β,18β,20β)-N-Eth-oxy-carbonyl-methyl-3-nitrato-11-oxoolean-12-ene-29-carboxamide methanol monosolvate.
abstract: The title compound, C(34)H(52)N(2)O(7)·CH(4)O, is the methanol solvate of a difunctionalized derivative of the therapeutic agent 18β-glycyrrhetinic acid, a penta-cyclic triterpene. The five six-membered rings of the glycyrrhetinic acid moiety show normal geometries, with four rings in chair conformations and the unsaturated ring in a half-chair conformation. This moiety is substituted by a nitrate ester group and an O-ethyl-glycine group. In the crystal, the nonsolvent mol-ecules are packed parallel to (010) in a herringbone fashion with the nitrato, ethyl-glycine and methanol-O atom being proximate. The methanol solvent mol-ecule is anchored via a donated O-H⋯O(ac-yl) and an accepted N-H⋯O hydrogen bond, giving rise to infinite zigzag chains of hydrogen bonds parallel to [100]. Two weak intermolecular C-H⋯O interactions to the methanol and to an acyl oxygen establish links along [100] and [010], respectively.
authors.forename: Laszlo
authors.initials: L
authors.lastname: Czollner
authors.forename: Ulrich
authors.initials: U
authors.lastname: Jordis
authors.forename: Kurt
authors.initials: K
authors.lastname: Mereiter