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|Title:||Facile acid-catalyzed condensation of ninhydrin with enols and aromatic compounds and microwave enhanced condensation of ninhydrin with hydroxy aromatic systems in solid state|
|Authors:||Kundu, Sandip Kumar|
|IPC Code:||Int.Cl.7 C 07 C 15/20|
|Abstract:||Di-and trihydroxybenzenes, 2,6-dihydroxyacetophcnone, α- and β-naphthols and also 3- and 4-hydroxycoumarins and various enols smoothly condense with ninhydrin in HOAc medium giving 2-substituted 1,3-dioxoindanes. Monoarylated products were also obtained upon microwave irradiation of the reactants adsorbed on silica gel. Reactions with corresponding methyl ethers are sluggish but are accelerated in the presence of conc. H2SO4 to 2,2-di substituted 1,3-dioxoindane stage. Under latter conditions monoarylated products are also further arylated paving the way for mixed 2,2-diaryl-l,3-dioxoindanes. Generally, ninhydrin adducts from phenols, naphthols and acyclic enols remain in intramolecular hemiketal form. AM1 computed heats of formation in some representative cases also favours such intramolecular hemiketal formation. A series of spirolactones have been generated through proper designing and synthesis of mono-arylated ninhydrin adducts.|
|Appears in Collections:||IJC-B Vol.43B(03) [March 2004]|
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