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Keto–enol tautomerism of β‐ketoamides and characterization of a sterically crowded α‐amido‐β‐ketoamide
Author(s) -
Sung Kuangsen,
Wu RuRong,
Sun ShuYi
Publication year - 2002
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.554
Subject(s) - tautomer , chemistry , enol , steric effects , keto–enol tautomerism , alkyl , nuclear magnetic resonance spectroscopy , stereochemistry , medicinal chemistry , organic chemistry , catalysis
An α‐amido‐β‐ketoamide ( 1 ) and two α‐alkyl‐β‐ketoamides ( 2 and 3 ) were prepared and characterized, and their keto–enol tautomerism was studied by H/ 13 C NMR spectroscopy. Both α‐alkyl‐β‐ketoamides 2 and 3 are in the keto form in CDCl 3 , and their enol forms cannot be detected by 1 H/ 13 C NMR spectroscopy, whereas the α‐amido‐β‐ketoamide 1 shows both keto and enol forms in CDCl 3 with an experimental K E of 0.70 at 298 K. Copyright © 2002 John Wiley & Sons, Ltd.