Knowledge about the absolute configuration of small bioactive organic molecules is essential in pharmaceutical research because enantiomers can exhibit considerably different effects on living organisms. X-ray crystallography enables chemists to determine an enantiopure compound due anomalous dispersion. Here, we present determination flavoring agent (+)-γ-decalactone, which liquid under ambien...

The crystal structure of the title compound, berkeleydione [systematic name; (5aS,7R,9S,11R,11aS)-methyl 9-hy-droxy-1,1,5,7,9,11a-hexa-methyl-14-methyl-idene-3,8,10-trioxo-1,3,4,5a,6,7,8,9,10,11,11a,12-dodeca-hydro-7,11-methano-cycloocta-[4,5]cyclo-hepta-[1,2-c]pyran-11-carboxyl-ate], C26H32O7, has been reported previously [Stierle et al. (2004 ▶). Org. Lett. 6, 1049-1052]. However, the absolut...

The absolute configuration of 3-benzoyl-4-hy-droxy-6,6-dimethyl-1,5,7-tris-(3-methyl-but-2-en-yl)bicyclo-[3.3.1]non-3-ene-2,9-dione, C(33)H(42)O(4), isolated from Hypericum hypericoides, has been determined. The previous study [Xiao et al. (2007 ▶). J. Nat. Prod.70, 1779-1782] gave only the established relative configuration. The three stereogenic centers are now established as 1R, 5R and 7S on...

The controversy over the absolute configuration of (+)-erythro-mefloquine, the less psychosis-causing enantiomer of the anti-malarial drug Lariam, has been resolved by Mosher ester crystallization. The configuration determined previously by physical methods is correct, whereas the configuration determined by three enantioselective syntheses is wrong.

The absolute configuration of the predominant Cecropia hormone, methyl 12,14-dihomojuvenate, has been determined to be methyl (E,E)-(10R,11S)-(+)-10,11-epoxy-7-ethyl-3,11-dimethyl-2, 6-tridecadienoate (I). The less abundant hormone, methyl 12-homojuvenate, can be presumed by analogy to have the corresponding 3,7,11-trimethyldienoate structure (II). The assignment has been established with micro...

THE TITLE COMPOUND [SYSTEMATIC NAME: 7α,12-dihy-droxy-8,12-abietadiene,11,14-dione or (4bS,8aS,10R)-3,10-dihy-droxy-2-isopropyl-4b,8,8-trimethyl-1,4,4b,5,6,7,8,8a,9,10-deca-hydro-phenanthrene-1,4-dione], C(20)H(28)O(4), is an abietane diterpen-oid, which was isolated from the roots of Premna obtusifolia (Verbenaceae). Its crystal structure has been reported previously [Chen et al. (2000 ▶). Jie...

a water soluble polysaccharide, hb-1, with a molecular weight of 23,930, was isolated from radix ranunculi ternati. by hot water extraction, ethanol precipitation, deproteination，ultrafiltration and gel-filtration column chromatography. its sugar composition was determined by glc as glc, ara, and gal in a molar ration of 16.071: 2.722: 1. and the absolute configuration of glc was identified as ...