Abstract

ALDERETE, JOEL B.; BELMAR, JULIO; PARRA, MARIA  and  ZUNIGA, CELIA. NMR AND DFT STUDY ON THE PROTOTROPIC TAUTOMERISM OF 3-METHYL-5-PYRAZOLONE. Bol. Soc. Chil. Quím. [online]. 2000, vol.45, n.1, pp.85-89. ISSN 0366-1644.  http://dx.doi.org/10.4067/S0366-16442000000100012.

The prototropic tautomerism of 3-methyl-5-pyrazolone was studied byusing Density Functional Theory along with ¹H, ¹³Cand ¹⁵N-NMR. The results show that for the isolated moleculeand low polarity solvent the 5PYR-1 tautomer, a keto form, is the predominant species. In DMSO solution the predominant tautomeric form is 5PYR3, a hydroxytautomeric species. For almost every atom an excellent agreement was foundbetween the experimental and calculated NMR spectra using GIAO method at DFT/B3LYP/6-311+G (2p,d) level

Keywords : NMR; tautomerism; pyrazolones; DFT; GIAOcalculations.