Characterization of Isomeric 1,2,4-Oxadiazolyl-N-Methylpyridinium Salts by Electrospray Ionization Tandem Mass Spectrometry

Abstract

The mass spectrometry behavior of 1,2,4-oxadiazolyl-N-methylpyridinium salts has been investigated. These substances are of current interest as perspective ionic liquids, compounds used as green solvents for synthesis, and for their catalytic properties. The studies have been developed through ESI-MS/MS experiments. The obtained results demonstrate that a readily distinction between the two isomeric classes, 3- N-methylpyridinium- and 5-N-methylpyridinium-1,2,4-oxadiazoles, is possible through ESI-MS/MS experiments. A deeper investigation on the principal fragmentation pathways of characteristic ions has been also developed.

Synthesis and Antibacterial Activity of Mono- and Bi-Cationic Pyridinium 1,2,4-Oxadiazoles and Triazoles

“…Column chromatography on silica gel, technical grade, pore size 60 Å, 230–400 mesh, and particle size 40–63 μm and TLC silica gel 60 F 254 on aluminium support were used. Compounds 3a – c , 4 , 5 , 6a – c , 9 , 10 , 11a – b , 12a – b , 14a – b , 15a – b , 16a – b , 17a – b , 18a – b , 19a – b , 20a – b , 21 , 22 , 23a – c , 24 , 25 , 27 , 28a – b , 29a – b , and 30a – b synthesis and characterization are in agreement with the previously reported data (see Supplementary Material ) [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 36 , 37 ].…”

“…In this work, the antibacterial activity of different mono- and bi-pyridinium salts with different lengths of the alkyl chain, fluorinated or not, and with different counter ions, was evaluated. Some of the N -alkylpyridinium salts and N -perfluoroalkylpiridinium salts taken into consideration have been previously reported for different applications, such as ILs or ionic liquid crystals (ILCs) [ 26 , 27 , 28 , 29 , 30 , 31 , 32 ]. These organic salts have an azole ring as a spacer (specifically, 1,2,4-oxadiazole or 1,2,4-triazole).…”