Efficient One-Pot Synthesis of Spiro[Indoline-3,11'-Pyrazolo[3,4-a]Acridine]- 2,10'(1'H)-Dione Derivatives Catalyzed by L-Proline

Abstract

An efficient eco-friendly procedure for the synthesis of spiro[indoline-3,11'-pyrazolo[3,4-a]acridine]-2,10'(1'H)-dione derivatives has been developed through a one-pot three-component condensation of 1H-indazol-6-amine, isatin, and 5,5-dimethyl cyclohexane-1,3-dione or cyclohexane-1,3-dione, in the presence of catalytic amount L-proline in EtOH at 60 °C conditions. The advantages of this protocol include mild reaction condition, green, and nontoxic solvent, high yield, and operational simplicity. IR, ¹H NMR, ¹³C NMR, HRMS spectras, and elemental analyses were used to identify the structures of all the synthesized compounds.

Graphical Abstract

Keywords:

• L-proline
• one-pot synthesis
• spiroindoline
• pyrazino[34-a]acridine
• 1H-indazol-6-amine

Additional information

Funding

We are grateful to the Natural Science Foundation for Colleges and Universities of Jiangsu Province (18KJB150024) and Science and Technology Development Fund of Nanjing Medical University (NMUB2018267) for financial support.