A regio- and stereocontrolled approach to the synthesis of 4-CF3-substituted spiro[chromeno[3,4-c]pyrrolidine-oxindoles] via reversible [3+2] cycloaddition of azomethine ylides generated from isatins and sarcosine to 3-nitro-2-(trifluoromethyl)-2H-chromenes
A one-pot three-component reaction of azomethine ylides generated in situ from isatins and sarcosine with 3-nitro-2-(trifluoromethyl)-2H-chromenes in i-PrOH at 55–60 °C leads to the kinetically controlled products – exo-spiro[chromeno[3,4-c]pyrrolidine-3,3′-oxindoles]. When this reaction is carried...
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Veröffentlicht in: | New journal of chemistry 2019, Vol.43 (47), p.18495-18504 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | A one-pot three-component reaction of azomethine ylides generated in situ from isatins and sarcosine with 3-nitro-2-(trifluoromethyl)-2H-chromenes in i-PrOH at 55–60 °C leads to the kinetically controlled products – exo-spiro[chromeno[3,4-c]pyrrolidine-3,3′-oxindoles]. When this reaction is carried out in 1,4-dioxane under reflux, the thermodynamically controlled endo-spiro[chromeno[3,4-c]pyrrolidine-1,3′-oxindoles] are preferably formed. The isomerization of the kinetic products in DMSO solution at different temperatures has been studied by NMR spectroscopy and the stepwise mechanism of reversible [3+2] cycloaddition has been confirmed. The cytotoxic activity of some CF3-substituted spiro[chromeno[3,4-c]pyrrolidine-oxindoles] against the HeLa cell line was evaluated by the MTT test. |
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ISSN: | 1144-0546 1369-9261 |
DOI: | 10.1039/c9nj04498a |