Processes for the preparation of pesticidal compounds

Patent metadata

Field	Value
Publication number	US-9901095-B2
Application number	US-201715485782-A
Country	US
Kind code	B2
Filing date	Apr 12, 2017
Priority date	Oct 17, 2013
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

The present application provides processes for making pesticidal compounds and compounds useful both as pesticides and in the making of pesticidal compounds.

First claim

What is claimed is:

1. A process comprising:
(a) halogenating and reducing 4-nitropyrazole to produce

3-chloro-1H-pyrazol-4-amine hydrochloride (1a)

with concentrated hydrochloric acid at a temperature between about 10° C. and about 20° C. with between about 1 and about 4 equivalents of triethylsilane and about 1 to 10 weight percent palladium on alumina;

(b) mono-acylating 3-chloro-1H-pyrazol-4-amine hydrochloride (1a) with acetic anhydride in the presence of a base to yield

(c) reacting 1(b) with a suitable halopyridine in the presence of a copper salt, an amine, and a base, to yield N-(3-chloro-1-(pyridin-3-yl)-1H-pyrazol-4-yl)acetamide (1c)

(d) reacting 1(c) with a suitable reducing agent in the presence of an acid to yield 3-chloro-N-ethyl-1-(pyridin-3-yl)-1H-pyrazol-amine (1d)

(e) reacting (1d) with between about 1 and about 2 equivalents of 3-chloropropionyl chloride in the presence of a inorganic base to yield N-(3-chloro-1-(pyridin-3-yl)-1H-pyrazol-4-yl)-N-ethylpropanamide (2a)

and
(f) reacting (2a) with a thiol HS-R 1 in the presence of a base to yield pesticidal thioethers (2b)

wherein R 1 is selected form the group consisting of C 1 -C 4 haloalkyl and C 1 -C 4 alkyl-C 3 -C 6 halocycloalkyl.

2. A process according to claim 1 , wherein R 1 is C 1 -C 4 haloalkyl.

3. A process according to claim 1 , wherein R 1 is CH 2 CH 2 CF 3 .

4. A process according to claim 1 , wherein R 1 is CH 2 (2,2-difluorocyclopropyl).

5. A process according to claim 1 further comprising oxidizing (2b) with an oxidizing agent comprising hydrogen peroxide to yield

6. The process of claim 1 , wherein the base in step (b) or step (e) is sodium bicarbonate.

7. The process of claim 1 , wherein step (b) is carried out at a temperature of from about 0° C. to about 10° C.

8. The process of claim 1 , wherein the halopyridine in step (c) is 3-bromopyridine or 3-iodopyridine.

9. The process of claim 1 , wherein the copper salt in step (c) is copper(I) chloride (CuCl), copper(II) chloride (CuCl 2 ), or copper(I) iodide (CuI).

10. The process of claim 1 , wherein the copper salt in step (c) is copper(I) iodide (CuI).

11. The process of claim 1 , wherein the base in step (c) is potassium phosphate (K 3 PO 4 ).

12. The process of claim 1 , wherein the amine in step (c) is N,N′-dimethylethane-1,2-diamine.

13. The process of claim 1 , wherein step (c) is carried out at a temperature of from about 50° C. to about 110° C.

14. The process of claim 1 , wherein step (c) is carried out in the presence of a polar solvent.

15. The process of claim 2 , wherein the polar solvent in step (c) is acetonitrile (MeCN), dioxane, or N,N-dimethylformamide.

16. The process of claim 1 , wherein the reducing agent in step (d) is a hydride source.

17. The process of claim 16 , wherein the hydride source in step (d) is sodium borohydride (NaBH 4 ).

18. The process of claim 1 , wherein the acid in step (d) is a Lewis acid.

19. The process of claim 18 , wherein the Lewis acid in step (d) is borontrifluoride etherate (BF 3 .Et 2 O).

20. The process of claim 1 , wherein the base in step (f) is potassium hydroxide (KOH).

Assignees

• Dow Agrosciences Llc

Inventors

• Yang Qiang
• Lorsbach Beth
• Whiteker Greg
• Roth Gary
• Deamicis Carl
• Clark Thomas
• Gray Kaitlyn
• Zhang Yu
• Muhuhi Joseck M

Classifications

• A01N43/56 Primary

  1,2-Diazoles; Hydrogenated 1,2-diazoles · CPC title

• C07D401/04

  directly linked by a ring-member-to-ring-member bond · CPC title

• Y10S424/10

  Insect repellent · CPC title

• A01N47/40

  the carbon atom having a double or triple bond to nitrogen, e.g. cyanates, cyanamides · CPC title

• C07D403/04

  directly linked by a ring-member-to-ring-member bond · CPC title