Process for the preparation of 4-amino-5-fluoro-3-halo-6-(substituted)picolinates
View Patent ↗4-Amino-5-fluoro-3-halo-6-(substituted)picolinates are conveniently prepared from 4,5,6-trichloropicolinates by a series of steps involving fluorine exchange, amination, halogen exchange, halogenation and transition metal assisted coupling.
1. A compound of the formula
wherein Y 2 represents H, Br or I, and R represents C 1 -C 4 alkyl, cyclopropyl, C 2 -C 4 alkenyl or phenyl substituted with from 1 to 4 substituents independently selected from halogen, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, C 1 -C 4 alkoxy or C 1 -C 4 haloalkoxy and R 1 represents C 1 -C 12 alkyl or an unsubstituted or substituted C 7 -C 11 arylalkyl.
2. The compound of claim 1 wherein R is 4-chloro-2-fluoro-3-methoxyphenyl.
3. The compound of claim 1 wherein R 1 is methyl, isopropyl, or benzyl.
4. The compound of claim 1 selected from the group consisting of:
propan-2-yl 4-amino-5-fluoro-6-(4-chloro-2-fluoro-3-methoxyphenyl)-picolinate,
benzyl 4-amino-6-(4-chloro-2-fluoro-3-methoxyphenyl)-5-fluoro-picolinate,
propan-2-yl 4-amino-3-iodo-5-fluoro-6-(4-chloro-2-fluoro-3-methoxyphenyl)picolinate,
propan-2-yl 4-amino-3-bromo-5-fluoro-6-(4-chloro-2-fluoro-3-methoxyphenyl)picolinate, and
methyl 4-amino-6-(4-chloro-2-fluoro-3-methoxyphenyl)-5-fluoropicolinate.