88988-84-5Relevant academic research and scientific papers
NMR STUDIES ON IMIDINES. VII. THE TAUTOMERISM OF MONO-N-ARYL SUBSTITUTED PHTHALIC IMIDINES. A 1H AND 13C NUCLEAR MAGNETIC RESONANCE STUDY.
Spiessens, Luc I.,Anteunis, M. J. O.
, p. 431 - 452 (2007/10/02)
1H and 13C NMR data indicate the presence of N-aryl substituted phthalic imidines to exist as 3-amino-1-N-arylimino-1H-isoindole compounds in DMSO-d6.In CDCl3 a tautomeric equilibrium mixture containing 20percent of the imino form is observed.The presence of a dimeric association through intramolecular H bonds is suggested.It is shown that intramolecular NH-N hydrogen bonds displace the tautomeric equilibrium toward the imino tautomer in 2-pyridyl substituted phthalic imidines.In the reaction product of phthalic imidine and 2,6-diaminopyridine, 11, two pairs of intramolecular NH-N hydrogen bonds result in the presence of both amino and imino tautomeric forms in the same molecular species.
NMR STUDIES ON IMIDINES. V. 1H AND 13C NUCLEAR MAGNETIC RESONANCE STUDY OF THE TAUTOMERISM AND GEOMETRICAL ISOMERISM OF 1,3-BIS(ARYLIMINO)ISOINDOLINES
Spiessens, Luc I.,Anteunis, Marc J. O.
, p. 205 - 222 (2007/10/02)
Detailed 1H and 13C NMR data are given for a series of 1,3-bis(arylimino)isoindilines and for two N-methyl derivatives: 1,3-bis(phenylimino)-2-methylisoindoline (6) and 3-N,N-methyl,p-tolylamino-1-(p-tolylimino)-1H-isoindole (7). --- The diimino form is shown to be the predominant tautomer in compounds 2 - 5 by 13C chemical shift comparison with model compounds 6 and 7. --- Geometrical isomerism about the exocyclic C=N (C-N) bonds is discussed.The imino model 6 adopts the (E,E) configuration exclusively.Th e amino model 7 is present in a 90:10 (Z,E:E,E) ratio with respect to the p-tolylimino substituent at C-1.Compounds 2 - 4 show a mixture of (Z,Z) and (Z,E) isomers in a ratio of about 70:30.The bis-pyridyl derivative 5 is present exclusively as the (Z,Z) geometrical isomer due to an intramolecular hydrogen bond bridging mechanism.
