Received 26 May 2008
(RS)-(±)-2-Methoxycarbonyl-3-tropinone is an important intermediate for the preparation of cocaine and its derivatives. The molecule in the title compound, C10H16NO3+·C4H5O6-, is present as the enol tautomer. The six-membered ring adopts a half boat conformation, and the five-membered ring a slightly distorted envelope conformation. There are intra- and intermolecular hydrogen bonds involving the hydroxyl, carboxyl groups and quaternary ammonium groups.
Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and publCIF (Westrip, 2008).
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: RK2093 ).
We thank the Shanghai Institute of Organic Chemistry for the X-ray data collection and analysis.
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