Magnetic Nano Cobalt Ferrite Catalyzed Synthesis of 4<i>H</i>-Pyrano[3,2-<i>h</i>]quinoline Derivatives under Microwave Irradiation

Abstract

A microwave irradiated magnetically separable nano cobalt ferrite catalyzed green method for the synthesis of 4-phenyl-4H-pyrano[3,2-h]quinolin-2-amine and 2-amino-4-phenyl-4H-pyrano[3,2-h] quinoline-3-carbonitrile derivatives through cyclization of aromatic aldehyde, acetonitrile/malononitrile and 8-hydoxyquinoline is developed and presented in this paper. The cubic magnetic cobalt ferrite nano particles were synthesized by sol-gel citrate precursor method and characterized by FT-IR, XRD, SEM and TEM techniques and the structures of the synthesized pyranoquinoline derivatives were assigned by IR, MASS and 1 H NMR techniques. The reaction is carried out in a domestic microwave oven with a heat-resistant microwave safe glass container with a lid.

Development of an efficient, one‐pot, multicomponent protocol for synthesis of 8‐hydroxy‐4‐phenyl‐1,2‐dihydroquinoline derivatives

“…Based on the experimental results and previous literature [ 74,92,93 ] a proposed mechanism of the reaction was shown in Scheme 2. According to proposed mechanism acetate ion facilitate the removal of H from 2 to yield I(i) while ammonium ion catalyzed the formation of iminium ion [ I(ii) ] which due to higher reactivity than carbonyl group expedite the Knoevenagel condensation between I(i) and I(ii) followed by elimination of ammonium ion to yield benzylidenemalononitrile [ I(iii) ].…”

7-Hydroxy-4-phenyl-1, 2-dihydroquinoline derivatives: synthesis via one-pot, three-component reaction and structure elucidation

“…Based on the experimental results and previous literature [65,74,75] a proposed mechanism of the reaction was shown in Scheme 1. According to proposed mechanism acetate ion facilitate the removal of H from 2 to yield A while ammonium ion catalyzed the formation of iminium ion (B) which due to higher reactivity than carbonyl group expedite the Knoevenagel condensation between A and B followed by elimination of ammonium ion to yield benzylidenemalononitrile (C).…”

Magnetically Separable Transition Metal Ferrites: Versatile Heterogeneous Nano‐Catalysts for the Synthesis of Diverse Bioactive Heterocycles

“…Bandaru et al . (Table ) developed a simple, rapid, efficient and environmentally benign microwave‐assisted protocol for the synthesis of a series of 2‐amino‐pyrano[3,2 ‐h ]quinolins ( 7 ) via one‐pot three‐component cyclization of aromatic aldehydes ( 1 ), malononitrile ( 5 ) or acetonitrile ( 5 a ) and 8‐hydoxyquinoline ( 6 ) using a catalytic amount of nano‐CoFe 2 O 4 in ethanol. The catalyst was recovered easily with an external magnet and reused five times without any significant loss in its activity.…”