ISSN:
1572-8854
Keywords:
Amino steroids
;
X-ray analysis
;
absolute configuration
;
epimers
;
hydrogen bonding
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
,
Physics
Notes:
Abstract Two epimers of 20-aminopregn-5-en-3β-ol differing in configuration at C(20) have been synthesized and their structures have been determined by single crystal X-ray diffraction methods. The (20R)-epimer (1) crystallized in the orthorhombic system, space group P212121, with a = 9.0432(5) Å, b = 13.3446(7) Å, c = 15.1086(8) Å, and Z = 4. The (20S)-epimer hydrochloride hydrate (2 hydrate) crystallized in the monoclinic system, space group C2, with a = 31.0501(3) Å, b = 11.8221(1) Å, c = 11.9703(2) Å, β = 98.5140(10)°, and Z = 8. The absolute configurations at the C(20) chiral centers for the title compounds were unequivocally established for the first time. The asymmetric unit cell of 2 hydrate contained two steroid molecules, A and B, two hydrochloride molecules, and two molecules of water. The crystal packing for both diastereomers was strongly influenced by the presence of intermolecular hydrogen bonding. The molecules of 1 were linked in a head-to-tail fashion via hydrogen bonds between the hydroxyl group of the ring A and the amino group of the side chain of the ring D. The two molecules A and B of 2 hydrate were held together in head-to-head and head-to-tail fashions by a three-dimensional network of hydrogen bonds involving chlorine ions, disordered water molecules, and hydroxyl–amino groups interactions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1009553022723
Permalink
