Direct Assembly of Functionalized 3-Hydroxypyridine N-Oxides via Cascade Nitration/Hydroxylative aza-Annulation
Chada Raji Reddy1, Uprety Ajaykumar1, Veeramalla Ganesh1
1Department of Organic Synthesis & Process Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad 500007, India.
Abstract:
Herein, we introduce an innovative method for the direct access to multisubstituted pyridine N-oxides (PyNOs) from an acyclic precursor, MBH-acetates of propiolaldehydes. The reaction proceeds through nitration, followed by hydroxylative aza-annulation in one pot involving the formation of two C-N and one C-O bonds. The method provides a diverse platform to access the pyridine N-oxides either with or without iodination at the C-6 position. The synthetic potential of this highly atom-economical protocol is exemplified by further functionalization of the pyridine N-oxides and accessing 3-hydroxypyridines.
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