Back to results
US 2001/0054559 A1Published application
Selective electrochemical reduction of halogenated 4-aminopicolinic acids
AssigneeDow AgroSciences LLC
InventorsKarl Leopold Krumel, Craig Joseph Bott, Michael Frederick Gullo, Carey Lee Scortichini, John Wesley Hull JR.
Life of this patent
Estimating the term…
Abstract
Halogen substituents in the 5-position of 4-aminopicolinic acids are selectively reduced in the presence of halogen substituents in the 3- and 6-positions by electrolysis.
Claims12
A process for the preparation of a 4-amino-3-halopicolinic acid of Formula I
- 7
- wherein
- X represents Cl or Br;
- Y represents H, F, Cl, Br or C1-C4 alkyl;
- and
- R independently represents H or C1-C4 alkyl
- which comprises passing a direct or alternating electric current from an anode to a cathode through a solution of a 4-amino-3,5-dihalopicolinic acid of Formula II
- 8
- wherein
- X, Y and R are as previously defined, and
- wherein
- both of X are either Cl or Br at a cathode potential of about −0.4 to about −1.7 volts relative to an Ag/AgCl (3.0 M Cl−) reference electrode and recovering the product, with the proviso that, when X is Cl, Y is not Br.
9 more elements
A process for the preparation of
- 10
- which comprises passing a direct or alternating electric current from an anode to a silver cathode through a basic aqueous solution of
- 11
- at a cathode potential of about −1.0 to about −1.4 volts relative to an Ag/AgCl (3.0 M Cl−) reference electrode, acidifying the reaction mixture and recovering the product.
1 more element
Dependencies are inferred from the claim text.