Strategies for the phase editing of relayed responses in 2D HMQC-TOCSY spectra

An NMR technique for the determination of proton vicinal couplings relayed at the carbon chemical shift is presented. With this technique, which is an extension of DEPT‐HMQC‐TOCSY, it is possible to generate phaseedited 2D NMR data in which the 1H13C relayed responses differ in phase as a function of the proton multiplicity of the carbon from whose proton(s) the response originates. A simple pulse scheme is presented to allow further simplification of the spectrum by eliminating the direct 1H13C correlations. Thus, responses arising from methines or methyls will be of opposite phase from responses originating from methylenes; direct correlations are eliminated to minimize congestion. An example is presented with the cardiac drug digoxin.