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A satellite-selective 1D-TOCSY method is developed for measuring long-range heteronuclear coupling constants between proton and proton bearing carbons. The comparison of two 1D-TOCSY spectra generated by selective inversion of each [super 13]C satellite of a certain proton signal, Hi, has helped in measuring the long-range heteronuclear couplings between protons of the same spin system as Hi and the carbon bonded to Hi.

An alternative scheme is proposed by using an optimized NMR diffusion filter that eliminates the nondesired peaks while retaining the signals of interest. This strategy has proved to be useful in three common deuterated solvents, namely, CD[CI.sub.3], DMSO-[d.sub.6], and C[D.sub.3]OD, resulting in clean spectra with no interference from solvent or water peaks.

This study presents a simple method for measuring long-range heteronuclear coupling constants between protons and proton-bearing carbons. The approach involves recording two conventional 1D-TOCSY experiments in which the offset of the selective proton pulse is set on the low- and high-frequency 13C satellites of an isolated proton signal, Hi. Long-range heteronuclear coupling values between the 13Ci bonded to Hi and the protons Hj,k…n that belong to the same spin system were easily determined from the relative displacement of the relayed Hj,k…n signals in the satellite-selective TOCSY spectra. The sense of the displacement indicated the sign of the coupling constants. [ABSTRACT FROM AUTHOR]

Interpretation of ¹H NMR spectra of organic compounds is sometimes hampered by the presence of strong peaks arising from residual nondeuterated solvent and water that obscure compound signals. Classical solvent suppression techniques such as presaturation or those based on pulsed field gradients are not effective in this regard because they also remove the compound resonances that overlap with the solvent signal being suppressed. Here, we propose an alternative scheme by using an optimized NMR diffusion filter that eliminates the nondesired peaks while retaining the signals of interest. This strategy has proved to be useful in three common deuterated solvents, namely, CDCl3, DMSO-d6, and CD3OD, resulting in clean spectra with no interference from solvent or water peaks. [ABSTRACT FROM AUTHOR]