Preparation of haloalkoxyarylhydrazines and intermediates therefrom
View Patent ↗The invention in this document is related to the field of preparation of haloalkoxyarylhydrazines and certain intermediates derived therefrom, where said intermediates are useful in the preparation of certain pesticides disclosed in U.S. Pat. No. 8,178,658.
1. A process comprising:
(1a) reacting a haloalkoxyaniline of Formula 1 with sodium nitrite to produce an intermediate diazonium salt of Formula 1.1; followed by
(1b) reducing said intermediate diazonium salt of Formula 1.1 to produce a haloalkoxyarylhydrazine salt of Formula 1.2;
wherein
R is (C 1 -C 6 )haloalkoxy;
n is 0, 1, or 2.
2. A process according to claim 1 further comprising:
(2a) reacting said haloalkoxyarylhydrazine of Formula 1.2 with an arylalkoxyimidate of Formula 2.2 to produce an intermediate iminohydrazine of Formula 3.1; followed by
(2b) cyclizing said intermediate iminohydrazine of Formula 3.1 using formate source to produce a 1,3-diaryltriazole of Formula 3.2;
wherein R 1 is NO 2 , C(═O)OH, or C(═O)O(C 1 -C 6 )alkyl; and R 2 is (C 1 -C 6 )alkyl.
3. A process according to claim 1 wherein R is trifluoromethoxy or pentafluoroethoxy.
4. A process according to claim 1 wherein (1a) a 1:1 molar ratio of the haloalkoxyaniline and sodium nitrite is used.
5. A process according to claim 1 wherein (1a) the reaction is conducted in water, formic acid, n-butanol, isopropanol, nitromethane, ethanol, methanol, acetic acid, or mixtures thereof.
6. A process according to claim 1 wherein (1a) the reaction is conducted in the presence of hydrochloric acid, nitric acid, phosphoric acid, sulphuric acid, boric acid, hydrofluoric acid, hydrobromic acid, perchloric acid, tetrafluoroboric acid, or mixtures thereof.
7. A process according to claim 1 wherein (1a) the pH of the reaction is from about −1 to about 1.
8. A process according to claim 1 wherein (1a) the reaction is conducted at a temperature from about −5° C. to about 5° C.
9. A process according to claim 1 wherein (1b) is conducted in water, formic acid, n-butanol, isopropanol, nitromethane, ethanol, methanol, acetic acid, or mixtures thereof.
10. A process according to claim 1 wherein (1b) the reaction is conducted in the presence of a reducing agent, said reducing agent is sodium dithionite, tin chloride, hydrogen, or ammonium formate.
11. A process according to claim 1 wherein (1b) the pH of the reduction reaction mixture is from about 9 to about 12.
12. A process according to claim 1 wherein (1b) the reaction is conducted at a temperature from about −5° C. to about 5° C.
13. A process according to claim 2 wherein (2a) is conducted in pyridine, lutidine, or mixtures thereof.
14. A process according to claim 2 wherein (2b) is conducted at a temperature from about 95° C. to about 100° C.
15. A process according to claim 2 wherein (2b) formate source is formic acid.
16. A process according to claim 2 wherein: R is pentafluoroethoxy; and R 1 is NO 2 , C(═O)OH, C(═O)OCH 3 , or C(═O)OCH 2 CH 3 .
17. A haloalkoxyarylhydrazine having the following structure