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

• US 9,598,368 B2
• Filed: 10/09/2013
• Issued: 03/21/2017
• Est. Priority Date: 01/25/2011
• Status: Expired due to Fees

• Current Assignee: Dow Agrosciences LLC (Corteva, Inc.)
• Original Assignee: Dow Agrosciences LLC (Corteva, Inc.)
• Inventors: Zhu, Yuanming, Whiteker, Gregory T., Arndt, Kim E., Renga, James M., Froese, Robert D. J.
• Primary Examiner(s): NORTHINGTON DAVI, ZINNA
• Application Number:
  US14/049,645
• Publication Number:
  US 20140046070A1
• Time in Patent Office: 1,259 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: C07D 213/79 Acids; Esters
• CPC Class Codes: C07D 213/803 Processes of preparation
• CPC Class Codes: C07D 213/807 by oxidation of pyridines or condensed pyridines
• CPC Class Codes: C07D 213/84 Nitriles

Abstract

4-Amino-3-chloro-5-fluoro-6-(substituted)picolinates are conveniently prepared from 3,4,5,6-tetrachloropicolinonitrile by a series of steps involving fluorine exchange, amination, reaction with hydrazine, halogenation, hydrolysis and esterification, and transition metal assisted coupling.

Claims

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

2. The process of claim 1 in which the coupling of step f) is performed prior to the hydrolysis and esterification of step e).

3. An improved process of increasing the amount of recoverable 3-chloro-4,5,6-trifluoropicolinonitrile (Formula B)