(4R,4aR,6S,7S,7aS)-6-Hydroxy-7-hy- droxymethyl-4-methylperhydrocyclo- penta[c]pyran-1-one chloroform solvate from Valeriana laxiflora

Abstract

The structure of an iridolactone isolated from Valeriana laxiflora was established as (4R,4aR,6S,7S,7aS)-6-hydroxy-7-hydroxy­methyl-4-methyl­per­hydro­cyclo­penta­[c]­pyran-1-one chloro­form solvate, C10H16O4·CHCl3. The two rings are cis-fused. The [delta]-lactone ring adopts a slightly twisted half-chair conformation with approximate planarity of the lactone group and the cyclo­pentane ring adopts an envelope conformation. The hydroxy group, the hydroxymethyl group and the methyl group all have [beta] orientations. The absolute configuration was determined using anomalous dispersion data enhanced by the adventitious inclusion of a chloro­form solvent mol­ecule. Hydro­gen bonding, crystal packing and ring conformations are discussed in detail.The structure of the title compound was determined in the Molecular Structure Laboratory of the Department of Chemistry, University of Arizona. The diffractometer was obtained with funds provided by the NSF (grant No. CHE9610374). This study was supported by NIH grant No. 5U01TW00316-10 awarded to BNT