NMR STUDIES ON IMIDINES. VII. THE TAUTOMERISM OF MONO-N-ARYL SUBSTITUTED PHTHALIC IMIDINES. A 1H AND 13C NUCLEAR MAGNETIC RESONANCE STUDY.
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.
Spiessens, Luc I.,Anteunis, M. J. O.
p. 431 - 452
(2007/10/02)
SYNTHESIS OF 1,3-DIIMINOISOINDOLINES FROM 2-CYANOBENZALDEHYDE. REACTION OF N-(2-CYANOBENZYLIDENE)ANILINES WITH ELEMENTAL SULFUR IN LIQUID AMMONIA AND AMINES
Various 1,3-diiminoisoindolines were obtained by treating N-(2-cyanobenzylidene)anilines with elemental sulfur in liquid ammonia and amines.A novel route to isoindoline from 2-cyanobenzaldehyde was developed.