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Structure of Manasse's dimer from endo ‐2‐hydroxyepicamphor by NOE difference spectroscopy
Author(s) -
Banks Malcolm R.,
Gosney Ian,
Grant Keith J.,
Reed David,
Hodgson Philip K. G.
Publication year - 1992
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260301015
Subject(s) - chemistry , dimer , anhydrous , spectroscopy , acetic acid , crystallography , nuclear magnetic resonance spectroscopy , mass spectrometry , analytical chemistry (journal) , stereochemistry , organic chemistry , physics , chromatography , quantum mechanics
Reduction of (1 R )‐(+)‐camphorquinone by zinc in acetic acid yields a mixture of endo ‐2‐hydroxyepicamphor and 3‐hydroxycamphor. The former undergoes reaction in anhydrous methanol with HCl gas to furnish a stable crystalline solid, first reported in 1902. High‐resolution electron impact mass spectrometry showed the solid to be a dimer of formula C 22 H 36 O 4 . The 13 C{ 1 H} spectrum showed 11 discrete environments, in keeping with a symmetrical dimer. High‐field 1 H NOE difference experiments were used to determine not only the connectivity but also the stereochemistry of the system. All of the NOE experiments are consistent with only one structure, that of the symmetrical dimer. In addition, 2D carbon‐proton correlation experiments (HETCOR) were used to assign unambiguously its 13 C{ 1 H} spectrum.