Influence of hydrogen bonds on the molecular structure and conformations of two (C30H48O2) pentacyclic triterpene isomers

• Autor(a) principal: Barbosa, L. C. A.
• Data de Publicação: 2012
• Outros Autores: Corrêa, R. S., Silva, S. R. Souza e, Duarte, L. P., Silva, G. D. F., Ellena, J., Doriguetto, A. C.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: https://doi.org/10.1134/S0022476612010210; http://www.locus.ufv.br/handle/123456789/22225
• topic: Maytenus imbricata; Pentacyclic triterpene; Crystal structure; Molecular conformation; Static disorder; Hydrogen bond

The structural study of two (C30H48O2) pentacyclic triterpene (PCTT) isomers is presented. These terpenes, known as 30-hydroxy-lup-20(29)-en-3-one (1) and (11α)-11-hydroxy-lup-20(29)-en-3-one (2), were isolated from Maytenus imbricata Mart. Ex Reissek (Celastraceae). The molecular structure of 1 and 2 differs in the position of the hydroxyl group. Both compounds crystallize in non-centrosymmetric space groups with two molecules in the asymmetric unit. The crystal structure of 1 shows a triclinic P1 space group (a = 9.5518(1) Å, b = 9.7083(1) Å, c = 14.4696(2) Å, α = 93.832(1)°, β = 102.833(1)°, and γ = 103.307(1)°), while compound 2 crystallizes in a monoclinic P21 one (a = 13.4439(16) Å, b = 14.4463(14) Å, c = 13.5224(9) Å and β = 99.703(8)°). The two molecules independent by symmetry of 1 differ slightly due to the presence of static disorder in oxygen atoms. In addition, the intermolecular geometries of 1 and 2 were analysed, and in each isomer the crystal packing is stabilized by O-H…O intermolecular hydrogen bonds and van der Waals forces.