ISSN:
1572-8854
Schlagwort(e):
brassinosteroids
;
steroids
;
natural products
;
crystal structure
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Geologie und Paläontologie
,
Physik
Notizen:
Abstract The compound (25R)-2α,3α-epoxy-5α-spirostan-6,23-dione, crystallizes as a hemi-ethyl acetate solvate, having two host molecules of similar conformation per molecule of ethyl acetate, in the asymmetric unit. The O atom of the epoxy group is α-oriented. The presence of the epoxy group disturbs the chair conformation in the ring A of the steroidal nucleus. Ring A has a C5α,C10β half-chair conformation. The six-membered rings B, C, and F have chair conformation as expected. The D ring adopts a C14α-envelope conformation and the E ring is midway between a C22α,O3β half-chair and a C22α-envelope conformations. The A/B, B/C, and C/D ring junctions are trans. Crystal data: C27H38O5·1/2C4H8O2, Monoclinic, space group P21, a = 7.7363(18) b = 28.769(12) c = 12.038(6) Å, β = 90.88(5), V = 2679.0(10) Å3, Z = 4. The packing of the molecules is assumed to be dictated by van der Waals interactions and by intermolecular C—H ··· O hydrogen bonds.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1023/A:1012277425969
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