Homonuclear long‐range correlation spectra from HMBC experiments by covariance processing

We present a new application of covariance nuclear magnetic resonance processing based on 1H13C‐HMBC experiments which provides an effective way for establishing indirect 1H1H and 13C13C nuclear spin connectivity at natural isotope abundance. The method, which identifies correlated spin networks in terms of covariance between one‐dimensional traces from a single decoupled HMBC experiment, derives 13C13C as well as 1H1H spin connectivity maps from the two‐dimensional frequency domain heteronuclear long‐range correlation data matrix. The potential and limitations of this novel covariance NMR application are demonstrated on two compounds: eugenyl‐β‐D‐glucopyranoside and an emodin‐derivative. Copyright © 2007 John Wiley & Sons, Ltd.

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