Process for conversion of cyanopyridines to nicotinamides and catalyst therefor, process for preparing said catalyst

Abstract

The present invention relates to an improved process for conversion of cyanopyridines to nicotinamides More particularly the present invention relates to preparation of nicotinamides and isonicotinamides which finds its usage in the preparation of anti-TB drug i.e. isoniazid and as an intermediate of vitamin B 12 . The present invention also relates to a process for a catalyst useful for the preparation of nicotinamide and isonicotinamide.

We claim:  
     
         1 . A process for conversion of cyanopyridines to nicotinamides comprising dissolving the cyanopyridine in water; adding a transition metal catalyst prepared in neutral medium, refluxing the reaction mixture, cooling filtering and washing the resultant mixture and evaporating the filtrate to dryness to obtain the product.  
     
     
         2 . A process as claimed in  claim 1  wherein the refluxing temperature is in the range of 100 to 115° C. and the refluxing time is in the range of 6 to 15 hours.  
     
     
         3 . A process as claimed in claims  1  wherein the refluxing is carried out for a period in the range of 8-13 hours.  
     
     
         4 . A process as claimed in  claim 1  wherein the amount of cyanopyridine dissolved in water is in the range of 0.8 to 2.0 moles for every 1.5 to 8.0 moles of water and the transition metal oxide catalyst is added to in an amount in the range of 0.01 to 0.03 moles.  
     
     
         5 . A process as claimed in  claim 1  wherein the catalyst used is manganese dioxide.  
     
     
         6 . A process as claimed in  claim 5  wherein manganese dioxide catalyst is prepared by Redox method using potassium permanganate and manganese salt solution in neural medium.  
     
     
         7 . A process as claimed in  claim 6  wherein the manganese salt is selected from manganese sulphate and manganese chloride.  
     
     
         8 . A process as claimed in  claim 1  wherein the product nicotinamide is more than 99% pure.  
     
     
         9 . A process as claimed in claims  1  wherein the cyanopyridines used is selected from 3-cyanopyridine and 4-cyanopyridine.  
     
     
         10 . A process for preparation of a catalyst useful for preparation of nicotinamide and isonicotinamide which comprises reacting potassium permanganate and manganous salt solution in neutral medium by drop wise addition of aqueous solution of manganous salt to aqueous solution of potassium permanganate with constant stirring, allowing the reaction mixture to stand, filtering the precipitate of MnO 2  and washing with distilled water, drying the precipitation to obtain the catalyst.  
     
     
         11 . A process as claimed in  claim 10 , wherein dropwise addition of aqueous solution of manganous salt to aqueous solution of potassium permanganate is carried out at temperature in range of 30 to 80° C. and for a time period in range of 30 minutes to 1 hour.  
     
     
         12 . A process as claimed in  claim 10  wherein the reaction mixture is allowed to stand for a time period in the range of 10 to 15 hours.  
     
     
         13 . A process as claimed in  claim 10  wherein the precipitate of manganese dioxide is dried in an air oven at 110° C. for 3-4 hours.  
     
     
         14 . A process as claimed in  claim 10  wherein the manganous salt is selected from manganese chloride and manganese sulphate.