Towards the automatic analysis of (1)H NMR spectra: Part 5. Confirmation of chemical structure with flow-NMR.

A shift comparison procedure, which allows the use of flow spectra in automatic structure confirmation, is described. The effect of imperfect proton scaling at the analysis stage, loss of solute resonances under large solvent signals and the intermittent detection of labile protons are considered. The derivation of a suitable threshold acceptance criterion in the absence of explicit knowledge of spectral prediction reliability is also discussed. The methodology yielded approximately 10-15% incorrect structure confirmation, but the exact number depends on the reliability of spectral prediction and the number of incorrect but closely related structures postulated.