TiO₂‐nanoparticles as efficient catalysts for the synthesis of pyridine dicarbonitriles

Abstract

The catalytic effects of two forms of nano‐TiO2, which are prepared via an ordinary or a magnetized process, are investigated in the synthesis of pyridine dicarbonitriles by one‐pot multicomponent reaction of 4‐methyl thiophenol, malononitrile, and aryl aldehydes. The results have shown that both prepared nano‐TiO2 exhibited high catalytic activities toward the synthesis of pyridine dicarbonitrile derivatives but the nano‐TiO2, which is prepared via a magnetized process, has shown better catalytic activity. Furthermore, this new catalytic method for the synthesis of pyridine dicarbonitriles provides rapid access to the desired compounds in high yields and so a simple work‐up procedure in the presence of water at room temperature. Therefore, this method represents a significant improvement incompatible of the other methods that are available for the synthesis of pyridine dicarbonitriles.

Montmorillonite K10 Clay Accelerated One‐Pot Multicomponent Synthesis of Substituted 2‐Amino‐3,5‐dicarbonitrile‐6‐phenylsulfanylpyridines: Experimental and Theoretical Investigation

“…Apart from organocatalysts, various nanomaterial‐based catalysts have also been employed [24–33] . Besides these above techniques, Bronsted acids, Lewis acids, and basic catalysts have also been used with limited success [34–50] .…”

“…Apart from organocatalysts, various nanomaterial-based catalysts have also been employed. [24][25][26][27][28][29][30][31][32][33] Besides these above techniques, Bronsted acids, Lewis acids, and basic catalysts have also been used with limited success. [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] In addition to the aforementioned catalysts, heterogeneous catalysts as well as ionic liquids have also been used.…”

A one-pot multicomponent K-10 clay catalyzed synthesis of 2-Amino-3,5-dicarbonitrile-6-thiopyridines

“…The multicomponent condensation of aldehyde, malononitrile, and thiol has been accomplished by using various organocatalysts such as Et3N [11], diethylamine [12], deep eutectic solvent (DES) [13], Baker's yeast [14], water extract of banana [15], tetra-n-butylammonium fluoride [16], o-Iodoxybenzoic acid [17], diethylamine [18], piperidine [19], imidazole [20], L-Arginine [21], N,N'-Di(1H-tetraazol-5-yl)-6H,12H-5,11ethanedibenzo[b,f][1,5]diazocine-3,9-dicarboxamide [22], choline methoxide [23] procuring target pyridines in 80-98% yields. Apart from organocatalysts, various nanomaterial-based catalysts have also been employed [24][25][26][27][28][29][30][31][32][33]. However, these methods suffered from prolonged reaction times and poor yields.…”