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Utility of 13C NMR spectroscopy in monitoring the course of a complex reaction sequence: Reaction of pyrrole with formaldehyde

✍ Scribed by Alan R. Katritzky; Kam Wah Law

Publisher
John Wiley and Sons
Year
1988
Tongue
English
Weight
395 KB
Volume
26
Category
Article
ISSN
0749-1581

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✦ Synopsis

The complex course of the reaction of pyrrole with formaldehyde has been completely elucidated by quantitative I3C NMR spectroscopy using the inverse-gated decoupling technique. The final product is 23bis(hydroxymethy1)pyrrole (with a free l-position), but three main intermediates containing 1-hydroxymethyl groups were identified, and the rise and subsequent fall of their populations followed. The intermediacy of additional compounds (formals) also renders the reaction more complex. The molar fractions of four hydroxymethylpyrroles present in the reaction mixtures were calculated from the I3C NMR data and plotted against time. At 45 and 65Β°C pyrrole reacted completely with formaldehyde in 1 h and in less than 30 min, respectively. This work illustrates the utility of the 13C NMR investigation of an industrially important reaction.

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