Rapid and Efficient Ultrasound-Assisted Method for the Combinatorial Synthesis of Spiro[indoline-3,4′-pyrano[2,3-c]pyrazole] Derivatives

Abstract

An efficient one-pot synthesis of spiro[indoline-3,4'-pyrano[2,3-c]pyrazole] derivatives by four-component reaction of hydrazine, β-keto ester, isatin, and malononitrile or ethyl cyanoacetate catalyzed by piperidine under ultrasound irradiation is described. This synthesis was confirmed to follow the group-assistant-purification chemistry (GAP) chemistry process, which can avoid traditional chromatography and recrystallization purifications.

Molecular diversity of spirooxindoles. Synthesis and biological activity

“…As can be seen from the literature, MCRs procedures use different catalysts, such as tris(2-hydroxyethyl)amine [137], L-proline [138], sodium stearate [139], [BMIm]BF 4 [140] as catalysts in an alcoholic or aqueous medium for the activation of these processes, as well as non-catalyst and solvent-free conditions [141][142][143]. The most recent research described a silica-bonded 5-n-propyloctahydropyrimido[1,2-a]azepinium chloride (SB-DBU)Cl as the heterogeneous silica-supported ionic liquid catalyst used for the efficient synthesis of spiro[4H -pyran-oxindoles] 244 [144].…”

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.…”

Ultrasound-promoted One-Pot, Three Component Synthesis Of Novel 5-Amino-2-(4-Chlorophenyl)-7- Substituted Phenyl-8,8a-Dihydro-7H-[1,3,4]Thiadiazolo[3,2-A]Pyrimidine-6-Carbonitrile Derivatives.

“…They have proven to be fast, convergent, atom efficient reactions and avoiding complicated purifications [12]. MCRs have emerged as a valuable tool in the synthesis of drug libraries because they have significant advantages over conventional reaction strategies to generate biologically active scaffolds with significant structural diversity [16].…”