Author(s)

Belén Gastaca¹, Hernán Rubén Sánchez², Fiorella Menestrina³, Maricel Caputo¹, María de las Mercedes Schiavoni¹, Jorge Javier Pedro Furlong^1*

¹Laboratory of Organic Compounds Studies (LADECOR), Department of Chemistry, Facultad de Ciencias Exactas, National University of La Plata, La Plata, Argentina.
²Institute of Physics of Liquids and Biological Systems (IFLySIB, CONICET), National University of La Plata, La Plata, Argentina.
³Laboratory of Research and Development of Analytical Methods (LIDMA), Department of Chemistry, Facultad de Ciencias Exactas, National University of La Plata, La Plata, Argentina.

Tautomeric forms of Thiosemicarbazones have been investigated by spectrometric methods, their chemical reactivity and theoretical calculations of the relative tautomers stabilities. The mass spectral fragmentation of thiosemicarbazones synthesized from acetophenones has been studied by CG/MS. The analysis of the corresponding spectra shows not only the regular fragmentation mechanisms but homolytic ruptures from even-electron species. 1H NMR spectra exhibit signals for the most intense open thioketo tautomeric structure, although when using TFA a ring structure is observed in the corresponding tautomeric equilibrium. Density Functional Theory calculations (DFT) also provide evidence to support the experimental observations by GC-MS and 1H NMR. Methylation reactions give support to the occurrence of the thioenol tautomeric form which would be the second most abundant according to the Density Functional Theoretical calculations.

Thiosemicarbazones, Tautomerism, MS, NMR, Theoretical Calculations

Gastaca, B. , Sánchez, H. , Menestrina, F. , Caputo, M. , Schiavoni, M. and Furlong, J. (2019) Thiosemicarbazones Synthesized from Acetophenones: Tautomerism, Spectrometric Data, Reactivity and Theoretical Calculations. International Journal of Analytical Mass Spectrometry and Chromatography, 7, 19-34. doi: 10.4236/ijamsc.2019.72003.