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Long‐range substituent and temperature effect on prototropic tautomerism in 2‐(acylmethyl)quinolines
Author(s) -
Gawinecki Ryszard,
Ośmiałowski Borys,
Kolehmainen Erkki,
Kauppinen Reijo
Publication year - 2001
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.356
Subject(s) - tautomer , chemistry , substituent , quinoline , pyrrolidine , medicinal chemistry , stereochemistry , organic chemistry
Tautomeric equilibria between 2‐(cinnamoylmethyl)quinoline, ( Z )‐1,2‐dihydro‐2‐(cinnamoylmethylene)quinoline and (Z)‐4‐phenyl‐1‐(2‐quinolyl)‐1,3‐butadien‐2‐ol were studied by 1 H, 13 C and 15 N NMR methods. The —CHCH— fragment conjugated with phenyl and a strong electron donor p ‐(1‐pyrrolidine) substituent were found to favour the enolimine tautomer. This undergoes fast exchange (on the NMR time‐scale) with the enaminone form. The amount of the latter tautomer was found to increase at low temperatures. Copyright © 2001 John Wiley & Sons, Ltd.