An efficient, regioselective amination of 3,5-disubstituted pyridine N-oxides using saccharin as an ammonium
Robert P Farrell1, Maria Victoria Silva Elipe, Michael D Bartberger
1Chemical Process Research and Development, Amgen Inc., One Amgen Center Drive, Thousand Oaks, California 91320, USA. rfarrell@amgen.com
Abstract:
A process for the regioselective amination of unsymmetrical 3,5-substituted pyridine N-oxides has been developed utilizing cheap, readily available saccharin as an ammonium surrogate. High conversions of the corresponding saccharin adducts have been achieved under mild reaction conditions. In situ deprotection under acidic conditions allows for a one-pot process to substituted aminopyridines. High regioselectivities were obtained from a variety of 3,5-disubstituted pyridine N-oxides.
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