Process for the preparation of 4-Amino-5-fluoro-3-chloro-6-(substituted)picolinates

Patent metadata

Field	Value
Publication number	US-9260392-B2
Application number	US-201314104127-A
Country	US
Kind code	B2
Filing date	Dec 12, 2013
Priority date	Dec 13, 2012
Publication date	Feb 16, 2016
Grant date	Feb 16, 2016

Abstract

4-Amino-5-fluoro-3-chloro-6-(substituted)picolinates are prepared from trifluoroacetic acid, p-methoxyaniline, a C 1 -C 4 alkyl propiolate and a substituted methylene amine by a series of steps.

First claim

What is claimed is:

1. A process for the preparation of a 4-amino-5-fluoro-3-chloro-6-(substituted)-picolinate of the Formula I

wherein
R 1 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 2 represents C 1 -C 4 alkyl,

which comprises the following steps:
a) contacting trifluoroacetic acid with p-methoxyaniline in the presence of a triarylphosphine and a trialkylamine base in carbon tetrachloride solvent to produce an acetimidoyl chloride of Formula A

b) contacting the acetimidoyl chloride of Formula A with a C 1 -C 4 alkyl propiolate (Formula B)

wherein R 2 is as previously defined,

in the presence of copper (I) iodide, an alkali metal iodide and an alkali metal phosphate in a polar aprotic solvent to produce an (imino)pent-2-ynoate of Formula C

wherein R 2 is as previously defined;
c) cyclizing the (imino)pent-2-ynoate of Formula C with an amine of Formula D

wherein R 1 is as previously defined,

in the presence of an inorganic alkali metal base in a polar aprotic solvent at a temperature from about ambient to about 100° C. to produce an alkyl 4-amino-5-fluoro-6-(substituted)-picolinate of Formula E

wherein R 1 and R 2 are as previously defined; and
d) halogenating and deprotecting the alkyl 4-amino-5-fluoro-6-(substituted)picolinate of Formula E with 1,3-dichloro-5,5-dimethylimidazolidine-2,4-dione (Formula F)

in the presence of a mineral acid in a polar solvent to produce the 4-amino-5-fluoro-3-chloro-6-(substituted)picolinate of the Formula I.

2. A process for the preparation of a 4-amino-5-fluoro-3-chloro-6-(substituted)-picolinate of the Formula I

wherein
R 1 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 i -C 4 haloalkoxy, and
R 2 represents C 1 -C 4 alkyl,

which comprises halogenating and deprotecting an alkyl 4-amino-5-fluoro-6-(substituted)-picolinate of Formula E

wherein R 1 and R 2 are as previously defined,

with 1,3-dichloro-5,5-dimethylimidazolidine-2,4-dione (Formula F)

in the presence of a mineral acid in a polar solvent to produce the 4-amino-5-fluoro-3-chloro-6-(substituted)picolinate of the Formula I.

Assignees

• Giampietro Natalie C
• Renga James M
• Dow Agrosciences Llc

Inventors

• Giampietro Natalie C
• Renga James M

Classifications

• C07D213/79 Primary

  Acids; Esters · CPC title

• C07D213/803 Primary

  Processes of preparation · CPC title

• C07C251/12

  being acyclic · CPC title