April 23, 2006, ACD/Labs ENC 2006 Academia Seminar, Pacific Grove, CA, USA

Unsymmetrical Covariance Processing of COSY or TOCSY and HSQC NMR Data to Obtain the Equivalent of HSQC-COSY and HSQC-TOCSY Spectra

David Adams

Abstract

Indirect Covariance NMR Spectroscopy has been recently described in a series of papers by Brüschweiler et al^1-6. In one of these reports,⁴ they describe a technique that allows the conversion of an HSQC-TOCSY spectrum into a ¹³C,¹³C-COSY spectrum. While this process is interesting, a much more intriguing possibility was conceived of and developed by Martin and co-workers^7-8. An unsymmetrical version of the covariance processing algorithm was developed in an effort to eliminate artifacts in the indirect covariance processing technique that arose due to proton resonance overlap.⁷ It was subsequently demonstrated using the unsymmetrical indirect covariance approach to combine HSQC and HMBC spectra⁸ to afford the equivalent of a m,n-ADEQUATE spectrum.^9-12 More recently, it has been shown that this approach can also be used to combine a HSQC and COSY or TOCSY dataset to derive the equivalent of an HSQC-COSY or HSQC-TOCSY spectrum.¹³

The initial report demonstrating the unsymmetrical indirect covariance processing of HSQC and COSY data showed that the data with nearly 10 times the signal-to-noise ratio of a conventional HSQC-COSY spectrum can be obtained by combining and HSQC and COSY spectrum in approximately 1/16^th the time required for the acquisition of the hyphenated HSQC-COSY spectrum.

Examples of spectra processed with this technique will be shown, as well, the process of transforming these spectra will be examined in detail.

References:

1. Brüschweiler, R.; and Zhang, F. J. Chem. Phys., 2004, 120, 5253-5260.
2. Brüschweiler, R. J. Chem. Phys., 2004, 121, 409-414.
3. Trbovic, N.; Smirnov, S.; Zhang, F.; and Brüschweiler, R. J. Magn. Reson., 2004, 171, 277-283.
4. Zhang, F. and Brüschweiler, R. J. Am. Chem. Soc., 2004, 126, 13180-13181.
5. Zhang F. and Brüschweiler, R. Chem. Phys. Chem., 2004, 5, 794-796.
6. Zhang, F.; Trbovia, N.; Wang, J.; Brüschweiler, R. J. Magn. Reson., 2005, 174, 219-222.
7. Blinov, K. A.; Larin, N. I.; Kvasha, M. P.; Moser, A.; Williams, A. J., and Martin, G. E. Magn. Reson. Chem., 2005, 43, 999-1007.
8. Blinov, K. A.; Larin, N. I.; Williams, A. J.; Zell, M.; and Martin, G. E. Magn. Reson. Chem., 2006, 44, 107-109.
9. Reif, B.; Köck, M.; Kerssebaum, R.; Kang, H.; Fenical, W.; and Griesinger, C. J. Magn. Reson., 1996, 118A, 282-285.
10. Köck, M.; Reif, B.; Fenical, W.; and Griesinger, C. Tet. Lett., 1996, 37, 363-366.
11. Köck, M.; Kerssebaum, R.; and Bermel, W. Magn. Reson. Chem., 2003, 41, 65-69.
12. Parella, T. and Sánchez-Ferrando, F. J. Magn. Reson., 2004, 166, 123-128.
13. Blinov, K. A.; Larin, N. I.; Williams, A. J.; Mills, K. A.; and Martin, G. E. J. Het. Chem., 2006, 43, 163-166.

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