title: (5R,8R)-2-(3,8-Dimethyl-2-oxo-1,2,4,5,6,7,8,8a-octa-hydro-azulen-5-yl)acrylic acid (rupestonic acid).
abstract: The title compound, C(15)H(20)O(3), crystallizes with two independent mol-ecules in the asymmetric unit. In both mol-ecules, the seven-membered ring adopts a chair conformation. In the crystal structure, inter-molecular O-H⋯O hydrogen bonds link the mol-ecules into chains extending in the [201] direction. The absolute configuration was assigned on the basis of the starting materials.
authors.forename: Haji Akber
authors.initials: HA
authors.lastname: Aisa
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Yong
authors.forename: Qiao-Ying
authors.initials: QY
authors.lastname: Lv
authors.forename: Tao
authors.initials: T
authors.lastname: Wu