Use of SO3H-functionalized halogenfree ionic liquid ([MIM(CH2)4SO3H] [HSO4]) as efficient promoter for the synthesis of structurally diverse spiroheterocycles

Sulfanilic acid functionalized mesoporous SBA-15: A water-tolerant solid acid catalyst for the synthesis of uracil fused spirooxindoles as antioxidant agents

“…20 Owing to their pharmaceutical importance, various synthetic methods for producing spirocyclic oxindoles have been reported. [21][22][23][24][25][26][27][28][29][30][31] Despite the efficiency of the reported protocols, some of them suffer from drawbacks such as long reaction time, harsh reaction conditions, corrosiveness, toxicity, cost, as well as unreusability of catalyst.…”

1,3-Diketones. Synthesis and properties

“…Ganguly et al [153] developed an efficient one-pot procedure for the synthesis of 9-(1H-indol-3-yl)xanthen-4(9H)-ones 223 by three-component reaction of dimedone with substituted 2-hydroxybenzaldehydes and 1(3)-substituted indoles in aqueous phase, catalyzed by L-proline (10 mol %) and an anionic surfactant, sodium dodecyl sulfite (SDS); the latter was taken in an amount exceeding its critical micelle concentration (0.08 mmol of SDS in 2 mL of water Multicomponent reaction of 2-amino-4-methylbenzothiazole with isatin and β-dicarbonyl compounds (including diketones) led to the formation of various spiro heterocyclic systems 225-227 [154]. Commercially available cyclic β-dicarbonyl compounds such as 1,3-dimethylbarbituric acid, dimedone, 4-hydroxy-coumarin, and 4-hydroxy-6-methylpyran-2-one were used as starting materials.…”

Synthesis and characterization of terbium doped TiO2 nanoparticles and their use as recyclable and reusable heterogeneous catalyst for efficient and environmentally sustainable synthesis of spiroannulated indolo[3,2‐c]quinolines‐ mimetic scaffolds of isocryptolepine

“…The present synthetic methodology involves the reaction of phenylhydrazine, with o-aminoacetophenone and cyclic ketones using nanostructured Terbium doped TiO 2 as recyclable and reusable heterogeneous catalyst. In view of medicinal importance of isocryptolepine structural framework and our research interest in the synthesis of drug-like hybrid molecules with privileged heterocyclic structures, [34][35][36][37][38][39][40][41][42][43][44][45] the present synthetic protocol is probably the first report for the synthesis of spiroannulated indolo […”