Processes for the preparation of pesticidal compounds

Patent metadata

Field	Value
Publication number	US-9029554-B1
Application number	US-201414517333-A
Country	US
Kind code	B1
Filing date	Oct 17, 2014
Priority date	Oct 17, 2013
Publication date	May 12, 2015
Grant date	May 12, 2015

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 for the preparation of 3-chloro-N-ethyl-1H-pyrazol-4-amine (7a) useful in the preparation of pesticidal thioethers (7b), (1e) and pesticidal sulfoxides (1f),

which comprises reducing N-(3-chloro-1H-pyrazol-4-yl)acetamide (1b)

with a suitable reducing agent in the presence of an acid.

2. The process according to claim 1 , wherein the reducing agent is a hydride source.

3. The process according to claim 1 , wherein the reducing agent is sodium borohydride.

4. The process according to claim 1 , wherein the acid is a Lewis acid.

5. The process according to claim 1 , wherein the acid is borontrifluoride etherate.

6. A process for the preparation of thioether (7b) useful as pesticides and in the preparation of pesticidal sulfoxides (1f),

wherein R 1 is selected from the group consisting of C 1 -C 4 haloalkyl and C 1 -C 4 alkyl-C 3 -C 6 halocycloalkyl, said process which comprises acylating 3-chloro-N-ethyl-1H-pyrazol-4-amine (7a)

with an acyl chloride of the formula C1C(O)CH 2 CH 2 SR 1 in the presence of a base.

7. The process according to claim 6 , wherein R 1 is C 1 -C 4 haloalkyl.

8. The process according to claim 6 , wherein R 1 is CH 2 CH 2 CF 3 .

9. The process according to claim 6 , wherein R 1 is C 1 -C 4 alkyl-C 3 -C 6 halocycloalkyl.

10. The process according to claim 6 , wherein R 1 is CH 2 (2,2-difluorocyclopropyl).

11. A compound 3-chloro-N-ethyl-1H-pyrazol-4-amine (7a)

12. A compound N-(3-chloro-1H-pyrazol-4-yl)-N-ethyl-3-((3,3,3-trifluoropropyl)thio)propanamide (Compound 4.7):

13. A process comprising:
(a) halogenating and reducing 4-nitropyrazole

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

(b) mono-acylation of 3-chloro-1H-pyrazol-4-amine hydrochloride (1a) to yield

with acetic anhydride in the presence of a base;
(c) reducing (1b) with a suitable reducing agent in the presence of an acid to yield 3-chloro-N-ethyl-1H-pyrazol-4-amine (7a)

(d) acylating (7a) wherein R 1 is selected from the group consisting of C 1 -C 4 haloalkyl and C 1 -C 4 alkyl-C 3 -C 6 halocycloalkyl, to yield thioether (7b)

(e) heteroaryling (7b) with a halopyridine in the presence of a copper salt, an amine, and a base to yield thioether (1e)

14. A process according to claim 13 wherein R 1 is C 1 -C 4 haloalkyl.

15. A process according to claim 13 wherein R 1 is CH 2 CH 2 CF 3 .

16. A process according to claim 13 wherein R 1 is C 1 -C 4 alkyl-C 3 -C 6 halocycloalkyl.

17. A process according to claim 13 wherein R 1 is CH 2 (2,2-difluorocyclopropyl).

18. A process according to claim 6 or 13 , in which the acyl chloride having the formula C1C(O)CH 2 CH 2 SR 1 wherein R 1 is CH 2 CH 2 CF 3 is prepared by the chlorination of

which has been prepared by the photochemical free-radical coupling of 3-mercaptopropionic acid with 3,3,3-trifluoropropene in the presence of 2,2-dimethoxy-2-phenylacetophenone initiator and long wavelength UV light in an inert organic solvent.

19. A process according to claim 6 or 13 , in which the acyl chloride having the formula C1C(O)CH 2 CH 2 SR 1 wherein R 1 is CH 2 CH 2 CF 3 is prepared by the chlorination of

which has been prepared by the low temperature free-radical initiated coupling of 3-mercaptopropionic acid with 3,3,3-trifluoropropene in the presence of 2,2′-azobis(4-methoxy-2,4-dimethyl) valeronitrile (V-70) initiator at temperatures of about 0° C. to about 40° C. in an inert organic solvent.

Assignees

• Dow Agrosciences Llc

Inventors

• Yang Qiang
• Lorsbach Beth
• Ross Jr Ronald
• Gray Kaitlyn
• Zhang Yu
• Roth Gary

Classifications

• C07D231/38

  Nitrogen atoms (nitro radicals C07D231/16) · CPC title

• A01N43/56 Primary

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

• C07D401/04 Primary

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

• C07C319/18

  by addition of thiols to unsaturated compounds · CPC title

• Y10S424/10

  Insect repellent · CPC title