The No-D NMR (No-Deuterium Proton NMR) technique is a measurement of high resolution 1H NMR spectra without using a deuterium solvent. With this technique many reaction mixtures or reagent solutions are directly available using
solvents. In conventional NMR measurements,
2H signals of deuterium solvent are used for shimming, however
1H solvent signals work just as well in No-D NMR measurements. Since suppression of strong
1H solvent signals by the WET pulse suppression sequence eliminates
13C satellite signals, it is a convenient approach to collect
1H NMR spectra without deuterium solvent by No-D NMR measurement.
When the compound with the exchangeable proton is dissolved in an exchangeable proton solvent (D2O, CD3OD, etc.), the proton is replaced with a deuterium atom. As a result, it is not possible to observe amino protons for the target molecule (Fig. 3 upper). On the other hand, the exchangeable proton can be observed in No-D NMR, since amino protons are not replaced while dissolved in a protonated solvent (Fig. 3 bottom).