Novel Rearrangement During the Reaction of Diethylmalonate with α-(5-Substituted 2-hydroxyphenyl)-N-phenyl Nitrones

Abstract

The hydroxyl group at the ortho position of the α-aryl ring of α-(2-hydroxyaryl)-N-aryl nitrones altered the expected course of the reaction between differently substituted α-(2-hydroxyaryl)-N-aryl nitrones and diethylmalonate, leading to the formation of an enamine involving an interesting rearrangement under microwave irradiation. The enamines have been characterized by NMR and x-ray analyses, and a reasonable mechanism has been put forwarded to explain the rearrangement.

Keywords:

• Diethyl malonate
• enamine formation
• microwave-assisted organic reactions
• nitrone addition

ACKNOWLEDGMENTS

The authors thank the Department of Science and Technology, New Delhi, India, for the NMR spectrometer facility. Financial support from Madurai Kamaraj University for one of the authors (S. R. J.) is gratefully acknowledged.