Redetermination of dihydro­artemisinin at 103 (2) K

Tthe structure of the title compound, C(15)H(24)O(5), has been redetermined at 103 (2) K, with much improved precision. The title compound was first reported by Luo, Yeh, Brossi, Flippen-Anderson & Gillardi [Helv. Chim. Acta (1984). 67, 1515–1522]. It is a derivative of the anti­malaria compound artemisinin and consists primarily of three substituted ring systems fused together. A cyclo­hexane ring (with a distorted chair conformation), is fused to a tetra­hydro­pyran group (also with a distorted chair conformation), and is adjacent to an oxacyclo­heptane unit containing an endoperoxide bridge. This gives the mol­ecule a unique three-dimensional arrangement. The crystal packing is stabilized by inter­molecular C–H⋯O and O–H⋯O inter­actions between an H atom from the cyclo­hexane ring and an O atom from the endoperoxide bridge, as well as between the hydroxyl H atom and an O atom from a tetra­hydro­pyran ring.