BMIm[OH] Catalyzed Rapid, Mild and Improved Protocol for the Synthesis of 3‐Hydroxy‐3‐(nitroalkyl)indolin‐2‐one Derivatives in Water.

A sustainable route for the Henry reaction of isatins with nitromethane or nitroethane to afford 3‐hydroxy‐3‐(nitroalkyl)indolin‐2‐ones was developed by the catalysis of 1‐butyl‐3‐methyl imidazolium hydroxide (BMIm[OH]) ionic liquid in water‐SDS system. Incorporation of SDS in the reaction medium enhances the reaction rate by suppressing the solubility issues for different substrates particularly for N‐alkylated isatins. This method provides high yield of the condensation product in a shorter reaction time under a very mild condition and in a multi‐gram scale reaction. Moreover, recyclability of the catalyst ionic liquid as well as reaction medium including surfactant makes the present protocol environmentally benign. [ABSTRACT FROM AUTHOR]