Acta Crystallographica Section B

Structural Science

Volume 56, Part 3 (June 2000)

Acta Cryst. (2000). B56, 512-525 [doi:10.1107/S0108768199015542]

Crystal chemistry of some synthetic 2-oxa-steroids: conformation, packing motifs and isostructurality

A. Anthony, M. Jaskólski and A. Nangia

Abstract: The crystal structures of six synthetic 2-oxa-steroids (A-ring lactone steroids) have been determined by single-crystal X-ray diffraction. The conformation and hydrogen bonding in these oxa-steroids is compared with packing motifs in the natural steroids and the anabolic agent, Anavar^®. O-HO hydrogen bonding with lactone carbonyl O is the preferred arrangement in molecules with a C-OH group. The donor H atoms of A, B and D rings participate in C-HO interactions with lactone carbonyl O and D-ring hydroxyl/ketone O acceptor atoms. The conformation of the lactone ring in these analogues is different from the natural androgens because replacement of the C2-methylene group by an O atom changes the geometry of the A ring. Two structurally related lactone steroids provide the first example of O-HO/C-HO interaction mimicry and furthermore the two components form a binary solid solution. The O-HO and C-HO hydrogen bonds in 2-oxa-steroid crystal structures are analysed and the observed preferences discussed in terms of geometric and chemical factors.

Online 1 June 2000


	Structure factor file (SHELXL table format) (41.4 kbytes) Supplementary material

	Structure factor file (SHELXL table format) (44.9 kbytes) Supplementary material

	Structure factor file (SHELXL table format) (44.5 kbytes) Supplementary material

	Structure factor file (SHELXL table format) (39.2 kbytes) Supplementary material

	Structure factor file (SHELXL table format) (41.1 kbytes) Supplementary material

	Structure factor file (SHELXL table format) (45.4 kbytes) Supplementary material

	Structure factor file (SHELXL table format) (40.0 kbytes) Supplementary material

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