US Patent 10259789 Process for the preparation of 4-alkoxy-3-acetoxypicolinic acids

4-Alkoxy-3-hydroxypicolinic acids may be conveniently prepared from 4,6-dibromo-3-hydroxypicolinonitrile in a series of chemical steps selected from bromo substitution, nitrile hydrolysis and halogen reduction that are conducted as a single pot process. 4,6-Dibromo-3-hydroxypicolinonitrile may be prepared from furfural in a series of chemical steps selected from cyano-amination, amine salt formation and bromination-rearrangement. 4-Alkoxy-3-acetoxypicolinic acids may be conveniently prepared from 4-alkoxy-3-hydroxypicolinic acids by treatment with acetic anhydride.