Nuclear magnetic resonance spectrometry origin

The biosynthetic origins of vanillin can be determined by the analysis of naturally occurring isotope ratios (in practice, chiefly 2H/1H and 13C/12C), using isotope ratio-mass spectrometry (IR-MS) and nuclear magnetic resonance (site-specific natural isotope fractionation SNIF-NMR ). Isotopic ratio... 

Structural investigations, using the molecular origin of the spectra to provide information which is often in support of nuclear magnetic resonance (NMR) or mass spectrometry studies. 

Bumamicine. This natural constituent isolated in trace quantities from Hmteria eburnea is included here because of its obvious relationship to corynantheol and because it represents a good example of the use of mass spectrometry in structure deduction. Bumamicine had an ultraviolet absorption maximum typical of a 2-acylindole which changed to that of a typical indole upon either sodium borohydride reduction or solution in acid. After the latter experiment the original chromophore was regenerated in basic solution. From the nuclear magnetic resonance spectrum the four aromatic protons, the ethylidene and the N-methyl were identifiable. The recovered alkaloid upon acetylation had an ultraviolet and nuclear magnetic resonance spectrum consistent for an ind N,0-diacetate (probably primary). 

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