Selective electrochemical reduction of halogenated 4-aminopicolinic acids
First Claim
Patent Images
1. A process for the preparation of a 4-amino-3-halopicolinic acid of Formula I whereinX 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 IIwhereinX, Y and R are as previously defined, and whereinboth 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.
1 Assignment
0 Petitions
Accused Products
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.
-
Citations
12 Claims
-
1. A process for the preparation of a 4-amino-3-halopicolinic acid of Formula I
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 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.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
wherein X and Y are as previously defined. -
3. The process of claim 1 in which the solution of the 4-amino-3,5-dihalopicolinic acid is a basic aqueous solution.
-
4. The process of claim 1 in which X is Cl and the cathode potential is from about −
- 0.8 to about −
1.7 volts.
- 0.8 to about −
-
5. The process of claim 4 in which Y is Cl.
-
6. The process of claim 5 in which the cathode potential is from about −
- 1.0 to about −
1.4 volts.
- 1.0 to about −
-
7. The process of claim 1 in which X is Br and the cathode potential is from about −
- 0.4 to about −
1.1 volts.
- 0.4 to about −
-
8. The process of claim 7 in which Y is Br.
-
9. The process of claim 8 in which the cathode potential is from about −
- 0.6 to about −
0.9 volts.
- 0.6 to about −
-
10. The process of claim 1 in which the cathode is silver.
-
11. The process of claim 10 in which the silver cathode has been activated by anodization in an aqueous caustic solution at a potential of at least +0.3 to about +0.7 volts followed by reverse polarization.
-
-
12. A process for the preparation of
which comprises passing a direct or alternating electric current from an anode to a silver cathode through a basic aqueous solution of 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.
- 1.0 to about −
Specification
-
- Resources
Litigation Campaign Assessment
Thank you for your request. You will receive a custom alert email when the Litigation Campaign Assessment is available.
×
-
Current AssigneeDow Agrosciences LLC (Corteva, Inc.)
-
Original AssigneeDow Agrosciences LLC (Corteva, Inc.)
-
InventorsGullo, Michael Frederick, Krumel, Karl Leopold, Hull, John Wesley Jr., Bott, Craig Joseph, Scortichini, Carey Lee
-
Primary Examiner(s)Wong, Edna
-
Application NumberUS09/760,325Publication NumberTime in Patent Office417 DaysField of Search205/426US Class Current205/426CPC Class CodesC07D 213/79 Acids; EstersC07D 213/803 Processes of preparationC25B 3/25 Reduction
