Acta Crystallographica Section C

Crystal Structure Communications

Volume 59, Part 3 (March 2003)

Acta Cryst. (2003). C59, o167-o170 [doi:10.1107/S0108270103001495]

The epimeric 9-oxobicyclo[3.3.1]nonane-3-carboxylic acids: hydrogen-bonding patterns of the endo acid and the lactol of the exo acid

M. M. Papadakis, J. A. Pavon, R. A. Lalancette and H. W. Thompson

Abstract: The two [bold delta] -keto carboxylic acids of the title, both C₁₀H₁₄O₃, are epimeric at the site of carboxyl attachment. The endo (3 [alpha] ) epimer, (I), has its keto-acid ring in a boat conformation, with the tilt of the carboxyl group creating conformational chirality. The molecules form hydrogen bonds by centrosymmetric pairing of carboxyl groups across the corners of the chosen cell [OO = 2.671 (2) Å and O-HO = 179 (2)°]. Two close intermolecular C-HO contacts exist for the ketone. The exo (3 [beta] ) epimer exists in the closed ring-chain tautomeric form as the lactol, 8-hydroxy-9-oxatricyclo[5.3.1.0^3,8]undecan-10-one, (II). The molecules have conformational chirality, and the hydrogen-bonding scheme involves intermolecular hydroxyl-to-carbonyl chains of molecules screw-related in b [OO = 2.741 (2) Å and O-HO = 177 (2)°].

Formula: Two isomers of C₁₀H₁₄O₃

Online 28 February 2003


	Structure factor file (CIF format) (78.3 kbytes) Contains datablock I

	Structure factor file (CIF format) (74.6 kbytes) Contains datablock II

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