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15N NMR spectroscopy 24—chemical shifts and coupling constants of α-amino acid N-carboxyanhydrides and related heterocycles

✍ Scribed by Hans R. Kricheldorf

Publisher: John Wiley and Sons
Year: 1980
Tongue: English
Weight: 599 KB
Volume: 14
Category: Article
ISSN: 0749-1581
DOI: 10.1002/mrc.1270140310

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✦ Synopsis

Abstract

The chemical shifts of amino acid N‐carboxyanhydrides (NCAs) and cyclic or linear urethanes are less sensitive to solvent effects than those of amides and lactams. The values of the one‐bond ^15^N^1^H coupling constants depend on the solvent and are 5‐8 Hz larger than those of ureas and amides. The ^15^N^13^C coupling constant of the NCO group is also unusually high, while that of the N—CH group lies within the range known for N‐acylated aliphatic amines. The one‐bond ^15^N^13^C coupling constant was found to be insensitive to conformational changes.

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