Three-component reaction of aldehydes with 3-(1H-indol-3-yl)-3-oxopropanenitrile and 1H-1,2,4-triazol-5-amine under the solvent-free condition at 70 °C was effectively performed in the presence of 2 mg of polyionic magnetic nanoparticles with pyrazine bridge [Fe3O4@SiO2@(CH2)3]2-Pyrazinium-[TCM]2 as a catalyst for the synthesis of 7-aryl-5-(1H-indol-3-yl)-[1,2,4]triazolo[1,5-a]pyrimidine-6-carbonitriles via a cooperative anomeric-based oxidation. The polyionic magnetic nanoparticles catalyst was simply recovered and reused four successive runs. The morphology and structure of MNPs catalyst were investigated by numerous techniques such as XRD, FT-IR, EDX, WDX, FE-SEM, TEM, TGA, DTA, and VSM. The obtained products are reported for the first time that were identified by various analyses techniques such as melting point, FT-IR, 1H NMR, 13C NMR, and elemental analysis (CHN). A term entitled a cooperative geminal-vinylogous anomeric-based oxidation was introduced for the latter step of the reaction mechanism for the first time. Synthesis of 7-aryl-5-(1H-indol-3-yl)-[1,2,4]triazolo[1,5-a]pyrimidine-6-carbonitriles by using [Fe3O4@SiO2@(CH2)3]2-Pyrazinium-[TCM]2 MNPs as a catalyst.
Keywords: 7-Aryl-5-(1H-indol-3-yl)-[1,2,4]triazolo[1,5-a]pyrimidine-6-carbonitrile; Anomeric effect; Anomeric-based oxidation; Magnetic nanoparticles; [Fe3O4@SiO2@(CH2)3]2-Pyrazinium-[TCM]2.
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