TY - JOUR
T1 - The epimeric 9-oxobicyclo[3.3.1]-nonane-3-carboxylic acids
T2 - Hydrogen-bonding patterns of the endo acid and the lactol of the exo acid
AU - Papadakis, Markos M.
AU - Pavon, Jorge A.
AU - Lalancette, Roger A.
AU - Thompson, Hugh W.
PY - 2003/3
Y1 - 2003/3
N2 - The two δ-keto carboxylic acids of the title, both C10H14O3, are epimeric at the site of carboxyl attachment. The endo (3α) 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 [O⋯O = 2.671 (2) Å and O-H⋯O = 179 (2)°]. Two close intermolecular C-H⋯O contacts exist for the ketone. The exo (3β) epimer exists in the closed ring-chain tautomeric form as the lactol, 8-hydroxy-9-oxatricyclo[5.3.1.03,8]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 [O⋯O = 2.741 (2) Å and O-H⋯O = 177 (2)°].
AB - The two δ-keto carboxylic acids of the title, both C10H14O3, are epimeric at the site of carboxyl attachment. The endo (3α) 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 [O⋯O = 2.671 (2) Å and O-H⋯O = 179 (2)°]. Two close intermolecular C-H⋯O contacts exist for the ketone. The exo (3β) epimer exists in the closed ring-chain tautomeric form as the lactol, 8-hydroxy-9-oxatricyclo[5.3.1.03,8]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 [O⋯O = 2.741 (2) Å and O-H⋯O = 177 (2)°].
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U2 - 10.1107/S0108270103001495
DO - 10.1107/S0108270103001495
M3 - Article
C2 - 12711798
AN - SCOPUS:0037359015
SN - 0108-2701
VL - 59
SP - o167-o170
JO - Acta Crystallographica Section C: Crystal Structure Communications
JF - Acta Crystallographica Section C: Crystal Structure Communications
IS - 3
ER -