Magnetically Separable Fe₃O₄@poly(m‐phenylenediamine)@Cu₂O Nanocatalyst for the Facile Synthesis of 5‐phenyl‐[1,2,3]triazolo[1,5‐c]quinazolines

Abstract

Herein we report a facile approach for the preparation of a magnetically separable Fe 3 O 4 @poly(m-phenylenediamine)-@Cu 2 O nanocatalyst and its catalytic efficiency in the synthesis of 5-phenyl-[1,2,3]triazolo [1,5-c]quinazolines from (E)-1-bromo-2-(2-nitrovinyl)benzenes, aldehydes, and sodium azide under mild reaction condition is described. The morphology, chemical composition, interior structure and magnetic properties of the Fe 3 O 4 @PmPDs@Cu 2 O nanocomposites were studied using powder X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron microscopy, vibrating sample magnetometer and nitrogen adsorption-desorption technique. The as-prepared Fe 3 O 4 @PmPDs@Cu 2 O nanocatalyst was simply recovered using external magnet and reused up to successive six runs with no obvious loss in its catalytic efficiency and structural integrity (confirmed by powder X-ray diffraction and transmission electron microscopy of recycled nanocatalyst) along with low leaching of copper (2.32 ppm) and iron (0.008 ppm) ions. The present protocol has a broad substrate scope with high yield in shorter reaction time and it does not require any additive or base. Overall, it has better green chemistry metrices like low E-factor (0.93), process mass intensity (1.93), high reaction mass efficiency (51.9 %) and carbon efficiency (95 %).

Palladium‐Catalyzed Three‐Component Process to [1,2,3]Triazolo [1,5‐c]quinazolines

“…reported the synthesis of 5‐phenyl‐[1,2,3]triazolo[1,5‐c]quinazolines from ( E )‐1‐bromo‐2‐(2‐nitrovin‐yl) benzene, aldehyde and sodium azide by multi‐component domino reaction (Scheme 1d). Subsequently, Rawat and co‐workers [13d] prepared a magnetically separable nanocatalyst and realized the construction of the skeleton (Scheme 1d). Although some achievements have been made in this field, in view of their importance, it is still quite attractive to explore novel and efficient protocols to enrich the synthetic strategies for the formation of these triazoloquinazolines.…”

Silver-Catalyzed Cascade Cyclization of Amino-NH-1,2,3-Triazoles with 2-Alkynylbenzaldehydes: An Access to Pentacyclic Fused Triazoles

“…In 2013, Shi et al [ 62 ] designed 4-( ortho -halo-aryl) 1,2,3-triazoles to merge with activated nitriles, forming a series of 5-amino-[1,2,3]triazolo-[5,1- a ]isoquinoline derivatives, a kind of valued tricyclic fused 1,2,3-triazoles ( Scheme 1 b). Though some achievements were reached in this field, there is still a lack of strategies for constructing interesting and complex fused 1,2,3-triazole derivatives, which attracts us considerably as we are persistently interested in this area [ 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 ]. Sparked by the vigorous performance of 2-alkynylbenzaldehyde in the synthesis of fused cyclic compounds [ 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 ], herein, we designed 2-(1 H -1,2,3-triazol-5-yl)anilines 1 to react with 2-alkynylbenzaldehydes 2 to construct isoquinolino [2,1- a ] [ 1 , 2 , 3 ] triazolo [1,5- c ] quinazolines 3 through a cascade process involving three C - N bond formations in one manipulation.…”