Nitrogen NMR spectroscopy: Application to some substituted pyrroles

✍ Scribed by Michael M. King; Herman J. C. Yeh; Gerald O. Dudek

• Publisher: John Wiley and Sons
• Year: 1976
• Tongue: English
• Weight: 584 KB
• Volume: 8
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1270080411

✦ Synopsis

Abstract

A series of ^15^N labeled 2‐acylpyrroles was prepared and the nitrogen and proton n.m.r. spectra obtained. ^15^N chemical shifts for these compounds are reported for the first time. No correlation between the nitrogen chemical shift and any Hammett substituent constant could be found. No variation in J(^15^NH) was observed for any compound with changes in solvent, temperature or concentration, ruling out any observable tautomeric equilibria for these systems. An increase in J(^15^NH) with the addition of electron withdrawing groups indicates increasing polarization of the NH bond and acidity of these molecules. Two and three bond ^15^N couplings are also reported.