An efficient one‐pot three‐component reaction for synthesis of spirooxindole derivatives in water media under catalyst‐free condition

Molecular diversity of spirooxindoles. Synthesis and biological activity

“…The diversely functionalized spirodihydropyran-oxindoles 225 have been obtained by using different metal-mediated carbonyl-addition/cyclization reaction sequences under Grubb's ruthenium-based catalysts (Scheme 60) [125]. 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].…”

Green Synthetic Approaches for Biologically Relevant 2-amino-4H-pyrans and 2-amino-4H-pyran-Annulated Heterocycles in Aqueous Media∗

“…However, Zhao et al [116] reported later on a catalyst-free synthesis of spirooxindole derivatives in water media under reflux conditions (Scheme 15). Besides, few synthetic methods for such scaffolds have recently been reported in aqueous media using nano-magnesium oxide (MgO) [117], DBU [118], and alum [119] as the effective homogeneous and heterogeneous catalysts (Scheme 15).…”

“…Few other varieties of spiroindole derivatives 34 were also synthesized from the one-pot condensation reaction between substituted isatins (20), malononitrile or ethyl cyanoacetate (3), and methyl/ethyl acetoacetate (33) in water medium using a various homogeneous or heterogeneous catalysts under reflux conditions (Scheme 17) [114][115][116][117].…”

“…A series of densely substituted spiroindole derivatives 35 were synthesized from the one-pot, three-component cyclocondensation reactions involving substituted isatins, active methylenic compounds, and varying 1,3-dicarbonyls Li et al [115] Zhao et al [116] Alum (35 mol% …”

Synthesis of novel pyrazolo[3,4-b]pyridine derivatives in aqueous medium

“…21 Moreover, the cost-effectiveness, abundance, noninflammability and non-toxic nature of water encourage its use. [22][23][24] Herein, we report the synthesis of new pyrazolo [3,4-b]pyridines 12a-m by the reaction of malondialdehydes 10a-c and electron-rich aminopyrazoles 11a-e in the presence of p-toluenesulfonic acid in water as a green solvent.…”