Synthesis and spectroscopic characterization of 2-furancarbothioamide: N-(4-fluorophenyl)furan-2-carbothioamide

LÓPEZ, JESSICA CARDONA; LEZAMA, JOSÉ OSVALDO GUY; BONESI, SERGIO MAURICIO; ROBLES, NORMA LIS

JOURNAL OF MOLECULAR STRUCTURE

ELSEVIER SCIENCE BV

Año: 2025

0022-2860

This investigation deals with an alternative thionation synthetic strategy for the preparation of N (4 fluorophenyl)¬furan 2 carbothioamide using elemental sulphur and applying the Willgerodt Kindler reaction. The carbothioamide was obtained with ca 30% yield assessing the purity (higher than 90%) with GC/MS spectrometry, and the compound was fully characterised by NMR (1H, 13C), FTIR and UV-visible spectroscopies. Indeed, 1H-NMR spectroscopic analysis demonstrated that a single conformer with anti-anti geometry was formed attributed to the observation of only one N H signal (9.37 ppm) of the NH C=S group and, FTIR spectroscopy (N H stretching at 3372 cm-1) also reinforces this observation. UV-visible absorption and fluorescence emission spectra were recorded in different polar and nonpolar solvents (acetonitrile, ethanol and n heptane) and the λ0,0 cross point displays a bathochromic shift of 11 nm with the increasing solvent polarity. The fluorescence quantum yield (φf) has been measured at room temperature concluding that this carbothioamide derivative is not a fluorescent compound showing a φf value of 0.0002. Finally, theoretical calculations have been carried out to estimate the NMR chemical shifts as well as vibrational frequencies values of the anti-anti isomer and these values were compared with the experimental data obtaining satisfactorily correlations.