Patent ID: 9598368
Date: 2017-03-21
CPC Classifications: C07D

Claim:
1. A process for the preparation of a 4-amino-3-chloro-5-fluoro-6-(substituted)picolinate of the Formula I wherein R represents C R which comprises the following steps: a) fluorinating 3,4,5,6-tetrachloropicolinonitrile (Formula A) with a source of fluoride ion to produce 3-chloro-4,5,6-trifluoropicolinonitrile (Formula B) b) aminating 3-chloro-4,5,6-trifluoropicolinonitrile (Formula B) with ammonia to produce 4-amino-3-chloro-5,6-difluoropicolinonitrile (Formula C) c) reacting the fluoro substituent in the 6-position of 4-amino-3-chloro-5,6-difluoropicolinonitrile (Formula C) with hydrazine to produce 4-amino-3-chloro-5-fluoro-6-hydrazinopicolinonitrile (Formula D) d) halogenating 4-amino-3-chloro-5-fluoro-6-hydrazinopicolinonitrile (Formula D) with a chlorine, bromine or iodine source to produce a 4-amino-3-chloro-5-fluoro-6-halopicolinonitrile of Formula E e) hydrolyzing and esterifying the 4-amino-3-chloro-5-fluoro-6-halopicolinonitrile of Formula E with a strong acid and an alcohol (R f) coupling the 4-amino-3-chloro-5-fluoro-6-halopicolinate of Formula F with an aryl, alkyl or alkenyl metal compound of the Formula G