Synthesis of Oxindoles, Spirooxindoles, and Isatins with Prominent Bioactive Probes: Review

Omprakash H Nautiyal
2018 Organic and Medicinal Chemistry International Journal  
3-Hydroxy-2-oxindoles ( Figure 1 ) are biologically useful active molecules, and efficient methods are needed for their synthesis under mild conditions. Wen-Ting Wei, have developed a base-and metal-free C (sp 3 )-H hydroxylation of 2-oxindoles. The reaction is promoted by TEMPO (2, 2, 6, 6-tetramethylpiperidine N-oxide) and synthesized under atmospheric air as a hydroxylation reagent in THF (tetrahydrofuran) at room temperature. Reaction mechanism proposed involves TEMPO reacting with the enol
more » ... cting with the enol form of the 2-oxindole, followed by a reaction with O 2 that generates a superoxide anion. This anion regenerates TEMPO and is converted to peroxide. Finally, the peroxide is cleaved to give the desired product. This concord provides a mild and simple strategy for the construction of C-O bonds from moderate to good yields. A wide range of substituted 2-oxindoles could be converted with a variety of functional groups.
doi:10.19080/omcij.2018.05.555671 fatcat:evres2xelvdanlmly52m5y2vje