Novel Sulfamic Acid–Promoted Synthesis of 3-Alkylidene Indolone Derivatives in the Presence of Aniline via One-Pot Multicomponent Reaction

Abstract

A sulfamic acid–catalyzed synthesis of 3-alkylidene indolone derivatives by addition of dialkyl acetylenedicarboxylate to isatin derivatives in the presence of aniline is reported. The reaction sequence consists of an initial Michael addition of aniline to dialkyl acetylenedicarboxylate, followed by aldol-like reaction with isatin, and then elimination of aniline to afford the product.

GRAPHICAL ABSTRACT

Keywords:

• Multicomponent reaction
• oxindole
• sulfamic acid

ACKNOWLEDGMENTS

The authors M. Damodiran and K. Karthikeyan thank the Council of Scientific and Industrial Research, New Delhi, India for senior research fellowships. The authors are grateful to SAIF, Indian Institute of Technology Madras, for recording single-crystal x-ray diffraction studies.

Notes

^a Isolated yield.

^a Three drops.

^b Isolated yield.

^c Determined by crude ¹H NMR.