(3β,18β,20β)-N-Ethoxycarbonylmethyl-3-nitrato-11-oxoolean-12-ene-29-carboxamide methanol monosolvate

Abstract

Key indicators: single-crystal X-ray study; T = 100 K; mean (C-C) = 0.003 Å; R factor = 0.044; wR factor = 0.122; data-to-parameter ratio = 13.4.The title compound, C 34 H 52 N 2 O 7 ÁCH 4 O, is the methanol solvate of a difunctionalized derivative of the therapeutic agent 18-glycyrrhetinic acid, a pentacyclic 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-ethylglycine group. In the crystal, the nonsolvent molecules are packed parallel to (010) in a herringbone fashion with the nitrato, ethylglycine and methanol-O atom being proximate. The methanol solvent molecule is anchored via a donated O-HÁ Á ÁO acyl and an accepted N-HÁ Á ÁO hydrogen bond, giving rise to infinite zigzag chains of hydrogen bonds parallel to [100]. Two weak intermolecular C-HÁ Á ÁO interactions to the methanol and to an acyl oxygen establish links along [100] and [010], respectively. Related literature