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

Abstract

This disclosure relates to the field of preparation of 3-(3-chloro-1H-pyrazol-1-yl)pyridine and intermediates therefrom. These intermediates are useful in the preparation of certain pesticides.

1 .- 8 . (canceled) 
     
     
         9 . A process for preparing 3-(3-chloro-4-methyl-1H-pyrazol-1-yl)pyridine (3) 
       
         
           
           
               
               
           
         
         comprising
 contacting 3-(3-chloro-4-methyl-4,5-dihydro-1H-pyrazol-1-yl)pyridine (2) 
 
       
       
         
           
           
               
               
           
         
         with an oxidant in a solvent at a temperature of about 25° C. to about 100° C. 
       
     
     
         10 . The process of  claim 9 , wherein the oxidant is selected from the group consisting of copper(I) chloride in the presence of oxygen, potassium ferricyanide, and manganese(IV) oxide. 
     
     
         11 . The process of  claim 9 , wherein the oxidant is used in about a 1.5 fold to about a 15 fold excess compared to 3-(3-chloro-4-methyl-4,5-dihydro-1H-pyrazol-1-yl)pyridine. 
     
     
         12 . The process of  claim 9 , wherein the solvent is selected from the group consisting of water, N,N-dimethylformamide, N-methylpyrrolidinone, dichloromethane, tert-butanol, acetonitrile, toluene, and mixtures thereof. 
     
     
         13 . The process of  claim 9 , wherein the oxidant is copper(I) chloride in the presence of oxygen, and the solvent is selected from the group consisting of N,N-dimethylformamide, N-methylpyrolidinone, and mixtures thereof. 
     
     
         14 . The process of  claim 9 , wherein the oxidant is potassium ferricyanide, and the solvent is water. 
     
     
         15 . The process of  claim 9 , wherein the oxidant is use manganese(IV) oxide, and the solvent acetonitrile. 
     
     
         16 . A process for preparing 3-chloro-1-(pyridin-3-yl)-1H-pyrazole-4-carboxylic acid (4) 
       
         
           
           
               
               
           
         
         comprising
 contacting 3-(3-chloro-4-methyl-1H-pyrazol-1-yl)pyridine (3) 
 
       
       
         
           
           
               
               
           
         
         with an oxidant in a polar protic solvent at a temperature of about 50° C. to about 100° C. 
       
     
     
         17 . The process of  claim 16 , wherein the oxidant is potassium permanganate or sodium permanganate. 
     
     
         18 . The process of  claim 16 , wherein the oxidant is used in about a 2.5 fold to about a 4.5 fold excess compared to 3-(3-chloro-4-methyl-1H-pyrazol-1-yl)pyridine. 
     
     
         19 . The process of  claim 16 , wherein polar protic solvent does not substantially react with the oxidant. 
     
     
         20 . The process of  claim 19 , wherein the polar protic solvent is selected from the group consisting of water, tert-butanol, tert-amyl alcohol, and mixtures thereof. 
     
     
         21 . The process of  claim 16 , wherein the oxidant is sodium permanganate, and the polar protic solvent is a mixture of water and tert-butanol.