Efficient Synthesis of Spiro[diindenopyridine-indoline]triones Catalyzed by PEG-OSO₃H-H₂O and [NMP]H₂PO₄

Abstract

One-pot, three-component synthesis of spiro[diindenopyridine-indoline]triones has been reported via the reaction of 1,3-indandione, aromatic amines, and isatins with (PEG-OSO₃H) as an efficient, polymeric acid surfactant–based catalyst in water and also in presence of acidic ionic liquid [NMP]H₂PO₄, which acts both as a medium and catalyst under conventional heating and ultrasonic irradiation. The reactions were complete in short reaction times with excellent yield of products. Surfactant-based PEG-OSO₃H could be recycled and reused several times without any significant loss of activity. The compounds exhibit fluorescence in methanol with large Stokes shift.

GRAPHICAL ABSTRACT

Keywords:

• Biodegradable
• multicomponent reactions (MCRS)
• [NMP]H₂PO₄
• PEG-6000
• polymeric
• spiro compounds
• water

Notes

^a Reaction carried out using 2.0 mmol of 1, 1.0 mmol of 2, and 1.0 mmol of 3.

^b Incomplete reaction.

^c Reaction performed under ultrasonic irradiation.

^a Reaction carried out using 2.0 mmol of 1, 1.0 mmol of 2, and 1.0 mmol of 3 in the presence of PEG-OSO₃H (30 mol%).

^b Reaction performed under conventional heating at 80 °C.

^c Reaction performed under ultrasonic irradiation at 40 °C.

^a Reaction carried out using 2.0 mmol of 1, 1.0 mmol of 2, and 1.0 mmol of 3 in the presence of [NMP]H₂PO₄ (30 mol%).

^b Reaction performed under conventional heating at 80 °C.

^c Reaction performed under ultrasonic irradiation at 40 °C.

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