Table of Contents
Journal of Crystallography
Volume 2013, Article ID 539163, 6 pages
http://dx.doi.org/10.1155/2013/539163
Research Article

16α-Hydroxyfriedelin and 3-Oxo-16-methylfriedel-16-ene as Building Blocks: Crystal Structure and Hirshfeld Surfaces Decoding Intermolecular Contacts

1Laboratório de Cristalografia, Instituto de Química, Universidade Federal de Alfenas (UNIFAL-MG), 37130-000 Alfenas, MG, Brazil
2Departamento de Química, Universidade Federal de São Carlos (UFSCar), 13561-901 São Carlos, SP, Brazil
3Departamento de Química, ICEx, Universidade Federal de Minas Gerais (UFMG), 31270-901 Belo Horizonte, MG, Brazil
4Departamento de Química e Exatas, Universidade Estadual do Sudoeste de Bahia (UESB), 45206-190 Jequié, BA, Brazil
5Departamento de Física e Informática, Instituto de Física de São Carlos (USP), 13560-970 São Carlos, SP, Brazil

Received 30 April 2013; Accepted 13 August 2013

Academic Editors: Lígia R. Gomes and Paul R. Raithby

Copyright © 2013 Rodrigo S. Corrêa et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In this paper the importance of C–HO intermolecular hydrogen bonds and van der Waals forces in crystal packing stabilization of 16α-hydroxyfriedelin (1) and 3-oxo-16-methylfriedel-16-ene (2) is described. Compound 1 is a natural product isolated from the hexane extract of Salacia elliptica branches, whereas compound 2 is obtained from compound 1 after dehydration accompanied by methyl migration of C-17 to C-16. The single-crystal X-ray diffraction experiments for 1 and 2 were carried out at 150 K, and the crystallographic study demonstrated that these compounds crystallize in noncentrosymmetric space groups, with 1 showing an orthorhombic P212121 space group and 2 a monoclinic P21 one. Compounds 1 and 2 are composed of five fused six-membered rings presenting a chair conformation, except for the central ring of 2, which adopts a half-chair conformation. In addition, the intra- and intermolecular parameters were studied using CCDC MOGUL analyses and Hirshfeld surfaces.