NMR computational study of acetaminophen and its chemical precursors

Abstract

In this research, a Nuclear Magnetic Resonance spectroscopic computational study of acetaminophen and its main chemical precursors: 4-nitrophenol and 4-aminophenol is presented. An optimization of all the molecular structures was performed. With the optimized structures, spectroscopic properties of nuclear magnetic resonance (NMR) were calculated. All calculations were performed using the structural electronic program GAUSSIAN 03^®. For the Hydrogen and Carbon spectra, Trimethylsilane (TMS) was used as the reference compound, for the Oxygen spectra water was used as reference and for Nitrogen, ammonia was used. The computational spectra of ¹H-NMR, ¹³C-NMR, ¹⁷O-NMR and ¹⁵N-NMR were compared with experimental spectra and NMR absorption tables of different atoms and functional groups obtained from the literature, showing the same absorption peaks in the calculated spectra. The main differences were due to the state of aggregation, since the computational calculations were carried out in the gas phase, without a solvent, while those obtained from the literature are obtained in deuterated solutions This shows that it is possible to perform NMR spectroscopic analysis using computational electronic calculations, with a high level of satisfaction, which can help in structural elucidation, in cases where it is impossible to use the experimental technique.