An expeditious access of 2,5′-dioxo-5′,6′,7′,8′-tetrahydro-1′H-spiro[indoline-3,4′-quinoline]-3′-carboxylate by reaction of isatin, ethyl cyanoacetate and enaminone in water

Approaches towards 3‐Substituted‐3‐hydroxyoxindole and Spirooxindole‐Pyran Derivatives in a Reaction of Isatin with Acetylacetone in Aqueous Media

“…The C 3 nucleophile of acetylacetone 2 a then attacks alkene of 7 which is followed by an internal attack by oxygen on the CN group to provide spirooxindole‐pyran derivative 5 a . The intermediate 7 has previously been reported by us as an intermediate in the multicomponent reaction of isatin …”

“…Recently, we disclosed synthetic protocols for a series of 3‐hydroxyoxindole and spirooxindole derivatives as a part of our research program directed towards the development of synthetic methodologies involving multicomponent reactions of isatin –. Further to expand our scope of the investigation, we planned to functionalize both C 1 and C 3 position of acetylacetone in a reaction with isatin using water as a reaction media.…”

Engaging Isatins in Multicomponent Reactions (MCRs) – Easy Access to Structural Diversity

“…In the same way, a catalyst‐free 3‐MCR between isatin, ethylcyanoacetate, and cyclic enaminones was explored by Tiwarni et al ., in an eco‐friendly manner (Scheme 69E and 69F). The library obtained (16 examples) could be prepared using only water as solvent, providing another example of a successful green approach to the synthesis of spirooxindoles [141] . The catalyst‐free preparation of a remarkable library of spiro[indoline‐3,4′‐pyrazolo[3,4‐ b ]pyridine] derivatives (50 examples) was also successfully achieved (Scheme 69G), using choline chloride and lactic acid (ChCl/Lac) as a recyclable and reusable reaction medium, showcasing the relevance of DESs as environmentally benign contributors in the field of multicomponent reactions [142]…”

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

“…Multicomponent reactions of isatins with malononitrile or ethyl ester of cyanoacetic acid are quite often also used in the preparation of indolone‐pyran spiro‐fused heterocycles [116–126] . The electrocatalytic multicomponent synthesis of nanoparticles of spirooxindole 31 was carried out using an electrogenerated base of the propanol anion in a one‐pot, three component condensations of isatins 22 , dimedone 32a , and malononitrile in an undivided cell in the presence of sodium bromide as an electrolyte at 50 °C.…”

“…In the case of 5‐nitroisatin (R 1 =H, R 2 =NO 2 ), the reaction productivity decreases (up to 85 %) ( Scheme 10 ,a ) [119] . The condensation of isatin 22 with 5‐anilino‐3,3‐dimethylcyclohexanone 32b (X=NHPh) and malononitrile in the presence of Et 3 N [120] or 5‐aminocyclohexanones 32c (R 2 =H or R 2 =CH 3 ) and ethyl cyanoacetate in water (80 °C, 5 h) [121] lead to regioselective formation of spiro‐fused oxindole derivatives 33a [120] or 33b [121] ( Scheme 10 ,b ).…”