Immobilization of trypsin onto polyamidoamine dendrimer functionalized iron oxide nanoparticles and its catalytic behavior towards spirooxindole-pyran derivatives in aqueous media

Fe3O4@SiO2@D‐NHCS‐Tr as an efficient and reusable catalyst for the synthesis of indol‐3‐yl‐4H‐chromene via a multi‐component reaction under solvent‐free conditions

“…The Fe 3 O 4 @SiO 2 @D-NHCS-Tr was prepared based on immobilization of trypsin onto PAMAM dendrimer functionalized magnetic nanoparticles [37]. It was synthesized via stepwise synthesis; then, its structure was characterized by diverse analyses such as FT-IR, TGA, TEM, SEM, EDX, and XRD (Scheme 1).…”

“…In previous work, we used this catalyst in the threecomponent reaction between isatins, 1,3-dicarbonyl compounds, and malononitrile (or ethyl cyanoacetate) to synthesis of spirooxindole-pyrans derivatives with excellent yields and short reaction times [37]. Now, we apply it in a new challenge for the synthesis of indol-3-yl-4Hchromene derivatives via multicomponent reactions.…”

“…As a result of these observations and in following of our previous work on the synthesis of heterocyclic compounds in the presence of catalyst [37][38][39][40][41][42][43][44][45][46][47], we want to report an effective and green method for the synthesis of indol-3-yl-4H-chromene derivatives using Fe 3 O 4 @SiO 2 @D-NHCS-Tr [37] reusable and heterogeneous nanobiocatalysts.…”

Expeditious entry into carbocyclic and heterocyclic spirooxindoles

“…A novel green synthesis of spirooxindole-pyran derivatives 81 via a three-component reaction of isatin 5a , malononitrile (or ethyl acetate) 14 , and 1,3-dicarbonyl compounds 15 was undertaken using water as a solvent (Scheme 51). 52 The reaction was catalyzed by magnetic Fe 3 O 4 @SiO 2 @D-NHCS-Tr nanocatalyst C 13 , which can be run up to six consecutive times without any significant loss in activity.…”