02361nas a2200253   4500008004100000022001400041245013400055210006900189260000800258300001100266490000800277520142800285653002801713653003101741653003401772653003701806653002701843653001901870100001801889700002901907700002401936700002201960856012501982       2022                        eng d  a2468-823100aEfficient cascade C-N coupling reactions catalyzed by a recyclable MoOx/ Nb2O5 nanomaterial for valuable N-heterocycles synthesis0 aEfficient cascade CN coupling reactions catalyzed by a recyclabl  cNOV  a1127420 v5323 a<p>
	The efficient cascade synthesis of pharmaceutically valuable N-heterocycles at solvent-free conditions was achieved using a robust, recyclable MoOx/Nb2O5 nanocatalyst. The results of catalyst screening revealed that the MoOx/Nb2O5 nanorods, calcined at 500 degrees C (MoNb5), exhibit excellent catalytic activity in the oxidative coupling of benzylamine with 96.5% conversion and &gt;99.6% selectivity to the desirable imine product. The uniform dispersion of Mo-oxide nanoparticles (average particle size: 5.2 +/- 0.5 nm) on shape-controlled Nb2O5 nanorods (width: 5.3 +/- 0.5 nm and length: 23-38 nm) in MoNb5 catalyst led to improved structural and acid properties, beneficial for the cascade C-N bond construction. The shape-controlled MoNb5 catalyst showed versatile activity in various cascade C-N coupling reactions to obtain 2-phenylbenzimidazole, 2-phenyl-quinaxoline, and 2-phenyl-2,3-dihydroquinazolin-4(1H)-one with good to excellent yields at solvent-free con-ditions. The optimum ratio of Lewis/Bronsted acid sites, the unique structure of Nb2O5 nanorods, and the strong MoO3-Nb2O5 interaction are the key reasons for the higher activity of MoNb5 catalyst. The efficient reusability of MoNb5 catalyst, its remarkable activity in diverse N-heterocycles synthesis, and efficient gram-scale synthesis emphasize its practical application for the cascade C-N coupling reactions under benign conditions.</p>
10aAcid sites optimization10aCascade C-N bond formation10aDiverse nitrogenous chemicals10aHeterogeneous nanosized catalyst10aMoO3-Nb2O5 interaction10aNb2O5 nanorods1 aSingh, Nittan1 aKalbande, Pavan, Narayan1 aUmbarkar, Shubhangi1 aSudarsanam, Putla  uhttps://library.ncl.res.in/content/efficient-cascade-c-n-coupling-reactions-catalyzed-recyclable-moox-nb2o5-nanomaterial