Impact of trace elements in the Grignard reaction

Patent metadata

Field	Value
Publication number	US-11697641-B2
Application number	US-202017442862-A
Country	US
Kind code	B2
Filing date	Mar 25, 2020
Priority date	Mar 27, 2019
Publication date	Jul 11, 2023
Grant date	Jul 11, 2023

Abstract

The present invention relates to an improved process for preparing 2,4-dichloro-6-(4-methoxyphenyl)-1,3,5-triazine (DICAT) comprising reacting 4-bromoanisole with magnesium, and reacting the resulting Grignard reagent with cyanuric chloride, wherein the magnesium comprises additional metals as impurities in an amount of less than 0.027% by weight, based on the total weight of the magnesium.

First claim

The invention claimed is:

1. A process for preparing a compound of formula I

comprising the steps of
(i) reacting 4-bromoanisole with magnesium to obtain a Grignard reagent; and
(ii) reacting the Grignard reagent obtained in step (i) with a compound of formula (II)

wherein the magnesium of step (i) comprises additional metals as impurities in an amount of less than 0.027% by weight, based on the total weight of the magnesium.

2. The process according to claim 1 , wherein the magnesium comprises the additional metals in an amount of less than 0.02% by weight, based on the total weight of the magnesium.

3. The process according to claim 1 , wherein the additional metals are selected from the group consisting of aluminum, manganese, silicon, iron, copper and calcium.

4. The process according to claim 1 , wherein the magnesium comprises magnesium oxide in an amount of less than 0.35% by weight, based on the total weight of the pure magnesium.

5. The process according to claim 1 , wherein the magnesium comprises metallic magnesium in an amount of more than 99.6% by weight, based on the total weight of the pure magnesium.

6. The process according to claim 1 , wherein the magnesium is provided in the form of shavings, powder or flakes.

7. The process according to claim 1 , wherein the compound of formula I is obtained in a yield of at least 95%.

8. The process according to claim 1 , wherein the solvent of one or both of step (i) and step (ii) is an aprotic solvent.

9. The process according to claim 1 , wherein the solvent is diethylether or tetrahydrofuran.

10. The process according to claim 1 , wherein the reaction temperature of step (i) is in the range of from 35° C. to 80° C.

11. The process according to claim 1 , wherein the reaction temperature of step (ii) is in the range of from 0° C. to 15° C.

12. The process according to claim 1 , wherein in step (i) the 4-bromoanisole is added to the magnesium, wherein the magnesium is provided in a solvent according to claim 8 , and in step (ii) the Grignard reagent obtained in step (i) is added to the compound of formula (II), wherein the compound of formula (II) is provided in a solvent according to claim 8 .

13. The process according to claim 1 , wherein in step (i) 4-bromoanisole and magnesium are reacted with each other in a molar ratio of from 1.2:1 to 1:1.2, or wherein in step (ii) the Grignard reagent obtained in step (i) is reacted with the compound of formula (II) in a molar ratio of from 1.2:1 to 1:1.2.

14. The process according to claim 1 , wherein the process further comprises reacting the compound of formula (I) with resorcinol in the presence of AlCl 3 to obtain a compound of formula (III)

15. The process according to claim 14 , wherein the process further comprises reacting the compound of formula (III) with isooctyl chloride in the presence of a base to obtain a compound of formula (IV)

16. The process according to claim 8 , wherein the solvent is selected from the group consisting of diethylether, tetrahydrofuran, trimethylamine and 1,4-dioxane.

17. The process according to claim 1 , wherein in step (i) 4-bromoanisole and magnesium are reacted with each other in a molar ratio of from 1.2:1 to 1:1.2, and wherein in step (ii) the Grignard reagent obtained in step (i) is reacted with the compound of formula (II) in a molar ratio of from 1.2:1 to 1:1.2.

Assignees

• Basf Se

Inventors

• Baeuchle Joerg
• Wiesenhoefer Wolfgang

Classifications

• C07D251/20 Primary

  with no nitrogen atoms directly attached to a ring carbon atom · CPC title

• C07D251/14 Primary

  with hydrogen or carbon atoms directly attached to at least one ring carbon atom · CPC title

• C07D251/28 Primary

  Only halogen atoms, e.g. cyanuric chloride · CPC title

• C07D251/24

  to three ring carbon atoms · CPC title