| abstract |
Improved methods of synthesizing 6-aryl-4-aminopicolinates, such as arylalky and alkyl 4-amino-3-chloro-6-(4-chloro-2-fluoro-3-methoxyphenyl)pyridine-2-carboxylates and arylalkyl and alkyl 4-amino-3-chloro-5-fluoro-6-(4-chloro-2-fluoro-3-methoxyphenyl)pyridine-2-carboxylates, are described herein. The improved methods include a direct Suzuki coupling step, which eliminates the protection/de-protection steps in the current chemical process, and therefore eliminates or reduces various raw materials, equipment and cycle time as well as modification of other process conditions including use of crude AP, use of ABA-diMe, and varying pH, catalyst concentration, solvent composition, and/or workup procedures. This invention was expanded to include synthesis of 2-aryl-6-aminopyrimidine-4-carboxylates. |