TAUTOMERISM AND SITE OF PROTONATION OF 1-METHYLCYTOSINE: PROOF BY NUCLEAR MAGNETIC RESONANCE SPIN-SPIN COUPLING.
New nuclear magnetic resonance data lead to a completely unambiguous proof that the predominant tautomeric form of 1-methylcytosine is the amino form and that in acid solution the molecule protonates at 3-N. The close similarity of the nuclear magnetic resonance spectra of this compound to the spectra of the cytosine nucleosides indicates that these structures also exist in the nucleosides. These conclusions are reached on the basis of the spectra of analogs labeled with N15 and of the proton spin decoupling measurements made at low temperature.
D002623:Chemistry Techniques, Analytical; D003596:Cytosine / Q000031:analogs & derivatives; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D011522:Protons; D012106:Research
D011522:Protons; C031532:1-methylcytosine; D003596:Cytosine
CHEMISTRY, ANALYTICAL; CYTOSINE; EXPERIMENTAL LAB STUDY