Process for the preparation of 3-(3-chloro-1;-pyrazol-1-yl)pyridine

• US 9,573,931 B2
• Filed: 05/03/2016
• Issued: 02/21/2017
• Est. Priority Date: 07/31/2014
• Status: Expired due to Fees

• Current Assignee: Dow Agrosciences LLC (Corteva, Inc.)
• Original Assignee: Dow Agrosciences LLC (Corteva, Inc.)
• Inventors: Buysse, Ann, Yang, Qiang, Lorsbach, Beth, DeAmicis, Carl, Ross, Ronald Jr., Li, Xiaoyong
• Primary Examiner(s): Morris, Patricia L
• Application Number:
  US15/145,152
• Publication Number:
  US 20160244427A1
• Time in Patent Office: 294 Days
• Field of Search: 546/275.4
• US Class Current: 1/1
• CPC Class Codes: C07D 401/04 directly linked by a ring-member-to-ring-member bond

Abstract

3-(3-Chloro-1H-pyrazol-1-yl)pyridine is prepared by coupling 3-bromopyridine with commercially available 3-aminopyrazole, purifying the 3-(3-amino-1H-pyrazol-1-yl)pyridine by crystallization, and converting the amino group to a chloro group by a Sandmeyer reaction.

Claims

1. A process for preparing 3-(3-amino-1H-pyrazol-1-yl)pyridine (8a)

2. The process of claim 1, further comprising

b) crystallizing the 3-(3-amino-1H-pyrazol-1-yl)pyridine (8a) from water.

3. The process of claim 1, wherein the treating is carried out in the presence of a water-miscible polar aprotic organic solvent.

4. The process of claim 3, wherein the water-miscible polar aprotic organic solvent is selected from the group consisting of acetonitrile, dimethyl sulfoxide, N-methylpyrrolidinone, N,N-dimethylformamide, and N,N-dimethylacetamide.

5. The process of claim 3, wherein the water-miscible polar aprotic organic solvent is N,N-dimethylacetamide.

6. The process of claim 1, wherein the copper chloride is copper (I) chloride or copper (II) chloride.

7. The process of claim 1, wherein the copper chloride is copper (I) chloride.

8. The process of claim 1, wherein the copper chloride is in an amount of from about 5 mole percent to 50 mole percent.

9. The process of claim 1, wherein the copper chloride is in an amount of from about 15 mole percent to 30 mole percent.

10. The process of claim 7, wherein the copper (I) chloride is in an amount of from about 15 mole percent to 30 mole percent.

11. The process of claim 1, wherein the 3-aminopyrazole is in an excess of about 10 mole percent to about 50 mole percent.

12. The process of claim 1, wherein the base is an alkali metal carbonate.

13. The process of claim 12, wherein the base in an excess of about 1.5 fold to about 2 fold.

14. The process of claim 12, wherein the alkali metal carbonate is potassium carbonate.

15. The process of claim 1, wherein the treating is carried out at a temperature of about 75°

C. to about 155°

C.

16. The process of claim 13, wherein the copper chloride is in an amount of from about 15 mole percent to 30 mole percent, the 3-aminopyrazole is in an excess of about 10 mole percent to about 50 mole percent, and the treating is carried out at a temperature of about 75°

C. to about 155°

C.