Synthesis of 2-amino-3-hydroxy-4-substituted pyridines via regioselective metalation of 3-(1-ethylpropyl)-[1,3]oxazolo[4,5-b]pyridin-2(3H)-one and application to corticotropin releasing factor1 receptor ligands

An efficient route to the preparation of 2-amino-3-hydroxy-4-substituted pyridines is described. The key step involves the regioselective metalation and subsequent alkylation of the [1,3]oxazolo[4,5-b]pyridin-2(3H)-one ring system. Base hydrolysis provides access to a variety of 4-substituted pyridines. This chemistry is proved to be useful for the synthesis of corticotropin releasing factor1 receptor ligands.