ISSN:
1572-8854
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Geologie und Paläontologie
,
Physik
Notizen:
Abstract (25R)-2,3,25,27-Tetrahydrophysalin A dimethanol solvate, C30H42O12, a derivative of 13,14-seco-16,24-cyclosteroid physalin A, crystallizes in the orthorhombic space groupP212121, witha=15.486(5),b=14.794(4), 12.248(6) Å andZ=4. The crystal structure has been solved by direct methods, and refined to an R-value of 0.053 for 2345 observed reflections.1H NMR spectral data of physalin A and its hydrogenated derivatives measured in dimethylsulfoxide-d6 solutions have been elucidated, based on the crystal structure of the tetrahydrophysalin A, enabling the assignment of all the proton signals of physalin A. Theβ-proton of C(11)-methylene has been shown to resonate at remarkably higher field due to anisotropic shielding effect of carbonyl group at C(15).
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF01186247
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