Step-economic, efficient, ZnS nanoparticle-catalyzed synthesis of spirooxindole derivatives in aqueous medium via Knoevenagel condensation followed by Michael addition

Synthesis of spirooxindole pyrimidines catalyzed by silica-bonded N-propyltriethylenetetramine as a recyclable solid base catalyst in aqueous medium

“…Known compounds were characterized by comparison of their IR, 1 H NMR, and 13 C NMR spectroscopic data and their melting points with reported values [4,5,[44][45][46][47][48][49][50][51][52][53][54][55].…”

“…Among them, the one-pot condensation reaction of isatin and activated methylene reagent could readily afford various spirooxindole pyramidine structures and has attracted wide attention, and this type of reaction has been achieved by a number of different catalysts and conditions, such as InCl 3 [43], electrochemical methods [44], triethylbenzylammonium chloride (TEBA) [45], Et 3 N [46], tetrabutylammonium fluoride (TBAF) [47], NH 4 Cl [48], lipase [4], p-TSA [49], ZnS nanoparticles [50], NaCl under sonication [51], butylmethylimidazolium tetrafluoroborate ([BMIm]BF 4 ) [52], amino-functionalized SBA-15 [53], CaCl 2 under ultrasonic irradiation [54], piperidine under ultrasonic irradiation [55], nanocrystalline MgO [56], gluconic acid [57], MnFe 2 O 4 nanoparticles [58], 1,8-diazabicyclo [5.4.0]undec-7-ene (DBU) [59], ethylenediammonium diformate (EDDF) [60], and sulfated choline based heteropolyanion [61] which some of them suffer from technical intricacy and generation of mixtures of pyrans and unsaturated nitriles.…”

Microwave-assisted Fe3O4 nanoparticles catalyzed synthesis of chromeno[1,6]naphthyridines in aqueous media

“…The use of nanomaterial as efficient catalysts in aqueous medium has attracted considerable interest [22][23]. The coupling of nanocatalyst with aqueous medium and MWs can offer an astonishing synergistic effect with superior potential than these components in solitude [24].…”

Sulfonic acid supported on Fe2O3/VO2 nanocatalyst: A highly efficient and reusable nanocatalyst for synthesis of spirooxindole derivatives

“…Various catalysts including carbon-SO3H [14], magnesium oxide (MgO) [15], ZnS NPs [16], triethylbenzyl ammonium chloride (TEBA) [17],…”