Model studies of pyridoxal Schiff's bases. Coplanarity and intramolecular hydrogen bonding.
The interactions between the pi cloud of the aromatic ring and the pi-electron pair of the imine double bond of aromatic oximes as model compounds of pyridoxal Schiff's bases have been studied by high-resolution carbon-13 magnetic resonance spectroscopy. The coplanarity and intramolecular hydrogen bonding have been determined by 13C-1H long range couplings. This detailed investigation of 13C-1H coupling also provides unambiguous proof of the existence of the "enol-imine" tautomers in chloroform and dimethyl sulfoxide solutions. The tautomerism between the "enol-imine" and "keto-enamine" is discussed.
D055598:Chemical Phenomena; D002621:Chemistry; D006860:Hydrogen Bonding; D008956:Models, Chemical; D008968:Molecular Conformation; D011730:Pyridoxal; D012545:Schiff Bases
D012545:Schiff Bases; D011730:Pyridoxal