PROCESS FOR PREPARING FLUOXASTROBIN

• US 20150011753A1
• Filed: 07/03/2014
• Published: 01/08/2015
• Est. Priority Date: 07/08/2013
• Status: Active Grant

• Current Assignee: Arysta Lifescience (Element Solutions Inc)
• Original Assignee: Arysta Lifescience (Element Solutions Inc)
• Inventors: Hindupur, Rama Mohan, Mane, Avinash Sheshrao, Balakrishnan, Sankar, Pawar, Jivan Dhanraj, Maddani, Mahagundappa Rachappa, Wadhwa, Sandeep, Prasad, Vic
• Granted Patent: US 9,193,698 B2
• Time in Patent Office: Days
• US Class Current: 544/65
• CPC Class Codes: C07D 273/00 Heterocyclic compounds containing rings having nitrogen and oxygen atoms as the only ring hetero atoms, not provided for by groups C07D261/00 - C07D271/00
• CPC Class Codes: C07D 273/01 having one nitrogen atom
• CPC Class Codes: C07D 413/12 linked by a chain containing hetero atoms as chain links

Abstract

The disclosure includes a process for preparing fluoxostrobin which includes:

• • (i) reacting benzofuran-3(2H)-one O-methyl oxime (10) with an alkyl nitrite in the presence of an acid to form (3E)-2,3-benzofuran-dione O³-methyl dioxime (11A) as a predominant isomer;

• • (ii) reacting (3E)-2,3-benzofuran-dione O³-methyl dioxime (11A) with 2-haloethanol to form (3E)-benzofuran-2,3-dione O²-(2-hydroxyethyl) O³-methyl dioxime (12A); and

• • (iii) reacting (3E)-benzofuran-2,3-dione O²-(2-hydroxyethyl) O³-methyl dioxime (12A) with a base to form (E)-(5,6-dihydro-1,4,2-dioxazin-3-yl)(2-hydroxyphenyl)methanone O-methyl oxime (13)

• • (iv) reacting a 4,6-di-halo-5-fluoro-pyrimidine (5), wherein X₁ is halogen, with (E)-(5,6-dihydro-1,4,2-dioxazin-3-yl)(2-hydroxyphenyl)methanone O-methyl oxime (13), in the presence of a solvent and optionally in the presence of a base, to form an (E)-(2-((6-halo-5-fluoropyrimidin-4-yl)oxy)phenyl)(5,6-dihydro-1,4,2-dioxazin-3-yl)methanone O-methyl oxime (14):

• • (v) reacting the (E)-(2-((6-halo-5-fluoropyrimidin-4-yl)oxy)phenyl)(5,6-dihydro-1,4,2-dioxazin-3-yl)methanone O-methyl oxime (14) with 2-chlorophenol, in the presence of a solvent and optionally in the presence of a base, to form fluoxastrobin:

Claims

1. A process for preparing fluoxastrobin, comprising:

(i) reacting benzofuran-3(2H)-one O-methyl oxime (10) with an alkyl nitrite in the presence of an acid to form (3E)-2,3-benzofuran-dione O³-methyl dioxime (11A) as a predominant isomer;

2. The process of claim 1, wherein X₁ is chlorine.

3. The process of claim 1, wherein the reacting the (E)-(2-((6-halo-5-fluoropyrimidin-4-yl)oxy)phenyl)(5,6-dihydro-1,4,2-dioxazin-3-yl)methanone O-methyl oxime (14) with 2-chlorophenol is carried out in the presence of a tertiary amine.

4. The process of claim 3, wherein the tertiary amine is 1,4-diazabicyclo[2.2.2]octane.

5. The process of claim 1, wherein steps (ii) to (v) are carried out as a one-pot process.

6. The process of claim 1, wherein the alkyl nitrite is n-butyl nitrite or t-butyl nitrite.

7. The process of claim 1, wherein the acid comprises hydrochloric acid, sulfuric acid, methanesulfonic acid, or phosphoric acid.

8. The process of claim 1, wherein a content of the (3E)-2,3-benzofuran-dione O³-methyl dioxime (11A) in a mixture of (3E)- and (3Z)-isomers is from 90% to 94%.

9. A process for preparing fluoxastrobin, comprising:

(i) reacting a 4,6-di-halo-5-fluoro-pyrimidine (5), wherein X₁ is halogen, with (Z)-(5,6-dihydro-1,4,2-dioxazin-3-yl)(2-hydroxyphenyl)methanone O-methyl oxime (15), optionally in the presence of a solvent and optionally in the presence of a base, to form a (Z)-(2-((6-halo-5-fluoropyrimidin-4-yl)oxy)phenyl)(5,6-dihydro-1,4,2-dioxazin-3-yl)methanone O-methyl oxime (16);

10. A process for preparing fluoxastrobin, comprising:

(i) reacting a 4,6-di-halo-5-fluoro-pyrimidine (5), wherein X₁ is halogen, with 2-chlorophenol, optionally in the presence of a solvent and optionally in the presence of a base, to form a 4-halo-6-(2-chlorophenoxy)-5-fluoropyrimidine (17);

11. The process of claim 9 or 10, wherein the isomerizing (Z)-fluoxastrobin to form fluoxastrobin is carried out in the presence of a solvent, and optionally an acid catalyst.

12. The process of claim 9 or 10, wherein the (Z)-(5,6-dihydro-1,4,2-dioxazin-3-yl)(2-hydroxyphenyl)methanone O-methyl oxime (15) is prepared by:

(iv) reacting benzofuran-3(2H)-one O-methyl oxime (10) with an alkyl nitrite in the presence of a base to form (3Z)-2,3-benzofuran-dione O³-methyl dioxime (11B) as a predominant isomer;

13. The process of claim 12, wherein the alkyl nitrite is n-butyl nitrite or t-butyl nitrite.

14. The process of claim 12, wherein the base in the reacting benzofuran-3(2H)-one O-methyl oxime (10) with an alkyl nitrite comprises a metal hydroxide, a metal hydride, and a metal alkoxide.

15. The process of any of claim 12, wherein a content of the (3Z)-2,3-benzofuran-dione O³-methyl dioxime (11B) in a mixture of (3E)- and (3Z)-isomers is 94% to 98%.

16. A process for preparing (E)-(5,6-dihydro-1,4,2-dioxazin-3-yl)(2-hydroxyphenyl)methanone O-methyl oxime (13)

17. A process of preparing (Z)-(5,6-dihydro-1,4,2-dioxazin-3-yl)(2-hydroxyphenyl)methanone O-methyl oxime (15)