New insight into experimental and theoretical mechanistic study on a green synthesis of functionalized 4H‐chromenes using magnetic nanoparticle catalyst

Abstract

A green synthesis of functionalized 4H-chromenes using one-pot, threecomponent reaction of salicylaldehyde (1), active methylene (2), and carbonbased nucleophile (3) using Fe 3 O 4 @CONa nanoparticles in water has been performed at 60 C. The Fe 3 O 4 @CONa nanoparticle as an efficient, green, and magnetically reusable heterogeneous catalyst was applied in these reactions up to the nine runs. Green catalyst and solvent, short reaction time, high product yields, as well as simple work-up procedure were found as some advantages of this methodology. The density functional theory calculations were applied to all-inclusive perception of the one-pot, three-component reaction mechanism. The most reactions progressed through the following route: (a) nucleophilic addition of 2 to 1; (b) ring closing, dehydration; (c) nucleophilic substitution of 3 (2-naphtol, 4-hydroxycumarin) to intermediate. Sometimes mechanism mutated to: (a) nucleophilic addition of 3 (indole, 2-methylindole) to 1, and dehydration; (b) nucleophilic addition of 2 to intermediate; and (c) ring closing, and dehydration. The frontier molecular orbitals, NBO analyses, molecular electrostatic potential of reactants, and intermediates confirmed the proposal mechanisms. Theoretical study could be so helpful to pick out suitable reactants of the reaction.

Solvent‐free synthesis of compounds containing chromene core catalyzed by novel Brønsted acidic ionic liquids‐ClO4

“…Although most of the previously reported catalysts [ 30–38 ] have proper ability to advance the reactions with good yields, some of them require harsh conditions, such as high reaction temperatures or long times, and others suffer from a problem in separating the catalyst from the reaction mixture and nonrecyclable catalyst. The features of this method, which makes it more preferable than other reported methods, are mild reaction conditions, environmentally benign, easy recovery of BAILs‐ClO 4 catalyst, reuse of the catalyst for six consecutive times without loss of catalyst performance, high yields of 2‐amino‐4 H ‐chromene derivative products, and short reaction times.…”

“…Due to the importance of the functionalized 4 H ‐chromenes, especially in medicinal chemistry, several synthetic protocols have been reported in the literature; that most of them suffer from some disadvantages such as multiple synthetic steps, boring reaction conditions, and expensive reagents. [ 30–38 ]…”

Fe3O4@C@prNHSO3H: A novel magnetically recoverable heterogeneous catalyst in green synthesis of diverse triazoles

“…Following our studies on the development of magnetic nano‐catalysts and their applications in the synthesis of organic compounds, [ 44–48 ] in this work, Fe 3 O 4 @C@PrNHSO 3 H was synthesized for the first time and applied in the one‐pot synthesis of pharmaceutically attractive diverse kinds of triazole derivatives via three‐component reactions to investigate the application scope of the novel heterogeneous core–shell magnetic nano‐catalyst.…”

Theoretical study of activation of O2 at cathode and CH3OH at anode of “CH3OH ‐O2” fuel cell using ZnC4H4 and CuC4H4 organometallic catalysts “a DFT study”

“…The adsorption of O 2 molecules onto BN nanoclusters has been studied theoretically. [24][25][26][27] Organometallic compounds are very famous and wide spread with the various applications. A compound, which has at least a chemical bond between carbon atom of an organic molecule and a metal, including the main metals or transition metals, refers to an organometallic compound.…”

“…The adsorption of O 2 molecules onto BN nanoclusters has been studied theoretically. [ 24–27 ]…”