One‐Pot, Three‐Component Synthesis of Novel Spiro[3H‐indole‐3,2′‐thiazolidine]‐2,4′(1H)‐diones in an Ionic Liquid as a Reusable Reaction Media

Abstract

A facile one-pot, three-component protocol for the synthesis of novel spiro[3H-indole-3,2'thiazolidine]-2,4'(1H)-diones by condensing 1H-indole-2,3-diones, 4H-1,2,4-triazol-4-amine and 2sulfanylpropanoic acid in [bmim]PF 6 (1-butyl-3-methyl-1H-imidazolium hexafluorophosphate) as a recyclable ionic-liquid solvent gave good to excellent yields in the absence of any catalyst (Scheme 1 and Table 2). The advantages of this protocol over conventional methods are the mild reaction conditions, the high product yields, a shorter reaction time, as well as the eco-friendly conditions.

Advances in the Synthesis of Benzo‐Fused Spiro Nitrogen Heterocycles: New Approaches and Modification of Old Strategies

“…[154] The known imine formation reaction by mixing of isatins with primary amines or ammonia in the presence of magnesium sulfate can also be successfully used to create spirocyclic molecules. [155][156][157] The imines, depending on structural factors and reaction conditions, can be used as precursors for generating azamethine ylides from them, capable of reacting with dipolarophiles. These imines easily enter also into cyclocondensation reactions.…”

Formation of spiro[indene-2,3′-pyrazole] derivatives from hydrazonyl chlorides and ninhydrin-malononitrile adduct

“…Spiroheterocycles are of considerable interest because the conformational restriction associated with the structural rigidity affects considerably their biological activity [1][2][3][4]. Among them, spiro-pyrazoles are the central structural frame works which are present in numerous bioactive natural products and alkaloids with biological and clinical activities [5][6][7][8].…”

[Et3NH][HSO4]-catalyzed eco-friendly and expeditious synthesis of thiazolidine and oxazolidine derivatives

“…To address the lack of convergent synthetic methods for the production of desired motifs, in this regard, ionic liquids (ILs) offer promising efficiency over other catalyzed reactions. [69][70][71] Till now, a very few ionic liquids have been reported so far for the synthesis of thiazolidine/ oxazolidine derivatives such as [Bmim][PF 6 ], 72,73 75 [Bnmim][Cl], 76 2-HEAP, 77 however these ionic liquids are of high cost as compared to simple ammonium ionic liquids. The rst report documented so far for the synthesis of thiazolidinones involving [Et 3 NH][HSO 4 ] was recently published by Maryam Kalantari 78 involving reaction between thiosemicarbazide, dimethylacetylene dicarboxylate (DMAD) and carbonyl compounds (Scheme 1).…”