Relayed Double-Quantum 2D-NMR Spectroscopy

Carbon-carbon connectivites for proton-bearing carbon atoms can be conveniently determined through a combination of COSY and 

COSY spectra. These experiments, however, do not allow assignments of quaternary carbon atoms, for which a COLOC 

INADEQUATE experiment was developed which records couplings betv/een directly connected carbon nuclei, but the sensitivity of the experiment is low. 

A new pulse sequence has recently been described in which C-relayed COSY spectra are obtained. The experiment allows assignments to quaternary carbon atoms. A ID-version ( C-relayed INEPT) of 

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S. Macura, N.G. Kumar, and L.R. Brown, Homonuclear relayed double quantum 2D NMR spectroscopy, J. Magn. Resonance 60,99 (1984) and references therein. 

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