Crystal structures of ecdysteroids: the role of solvent molecules in hydrogen bonding and isostructurality

Fabian, L., Argay, G., Kalman, A. and Bathori, M. (2002) Crystal structures of ecdysteroids: the role of solvent molecules in hydrogen bonding and isostructurality. Acta Crystallographica Section B, 58. pp. 710-720. ISSN 0108-7681

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Abstract

Three crystal forms of the steroid 20-hydroxyecdysone were identified by single-crystal X-ray diffraction analysis: a solvent-free modification, a methanol solvate hydrate and a trihydrate. The structure of a closely related steroid, polypodine B (the 5,20-dihydroxy derivative of ecdysone), was determined in its monohydrate form. Since the unit-cell volume of unsolvated 20-hydroxyecdysone was found to be considerably smaller than that of ecdysone [Huber & Hoppe (1965). Chem. Ber. 98, 2403-2424], a new structure determination of ecdysone was performed, which confirmed the unexpected difference between the unit-cell volumes. The crystals of ecdysone and 20-hydroxyecdysone are isostructural, while the mixed solvate of 20-hydroxyecdysone is homostructural with the hydrate of polypodine B. A detailed analysis of the hydrogen-bond networks in these closely related crystal pairs highlights their packing similarities, demonstrates the role of solvent molecules, and explains the unexpectedly small cell volume of 20-hydroxyecdysone.

Item Type: Article
Uncontrolled Keywords: 20-hydroxyecdysone,patterns
Faculty \ School: Faculty of Science > School of Pharmacy
Depositing User: Rachel Smith
Date Deposited: 19 May 2011 10:49
Last Modified: 31 Oct 2019 14:05
URI: https://ueaeprints.uea.ac.uk/id/eprint/30975
DOI: 10.1107/s0108768102005608

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