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organic compounds
The crystal structures of 17, 17-ethylenedioxyandrost-4-ene-3,6-dione, C21H28O4, and 17, 17-ethylenedioxyandrosta-1,4-diene-3,6-dione, C21H26O4, intermediates in the synthesis of heteroandrogenic aromatase inhibitors, have been determined. Both structures are stabilized by C— HO hydrogen bonds, highlighting the importance of weak interactions in influencing packing motifs in general and the conformation of the flexible dioxolane ring in particular.