Utilizing unsymmetrical indirect covariance processing to define 15N-13C connectivity networks

There has been considerable interest over the past decade in the utilization of direct and long-range H-1-N-15 heteronuclear shift correlation methods at natural abundance to facilitate the elucidation of small molecule structures. Recently, there has also been a high level of interest in the exploration of indirect covariance NMR methods. Our initial explorations in this area led to the development of unsymmetrical indirect covariance methods, which allow the calculation of hyphenated 2D NMR spectra such as 2D GHSQC-COSY and GHSQC-NOESY from the discrete component 2D NMR experiments. We now wish to report the utilization of unsymmetrical indirect covariance NMR methods for the combination of H-1-C-13 GHSQC and H-1-N-15 long-range (GHMBC, IMPEACH-MBC, CIGAR-HMBC, etc.) heteronuclear chemical shift correlation spectra to determine N-15-(13) C correlation pathways. Copyright (c) 2007 John Wiley & Sons, Ltd.