Oxidative Nuclear Bromination of Substituted 4-Pyridones Using Pyridinium Bromochromate

Abstract

An alternative convenient approach for the bromination of various poly-substituted 4-pyridones has been developed via an oxidative nuclear bromination in the presence of sole pyridinium bromochromate (PBC). The PBC performs the dual role of oxidant and source of Br⁺ during the process.

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GRAPHICAL ABSTRACT

Keywords:

• Bromopyridone
• oxidative bromination
• oxidative nuclear bromination (ONB)
• pyridinium bromochromate (PBC)
• 4-pyridone

ACKNOWLEDGMENTS

We thank the NSFC (21002051, 21172056, and 21272057), PCSIRT (IRT1061), China Postdoctoral Science Foundation (2012M521397), and the Foundation and Frontier Technology Research Program of Henan Province (112300410312) for financial support of this research.

Notes

^a All reactions were carried out with 1 (0.2 mmol) and PBC (1.1 equiv.) in AcOH (1.0 mL) at 50 °C in an oil bath.

^b Isolated yield.

^c 76% 3j and 14% 4j were obtained, and 10% 1j was recovered.

^d 47% 3k and 23% 4k were obtained, and 12% 1k was recovered.