Reaction #3743

Reaction equation

tert-butyl alcohol

sulfuric acid

2-cyanopyrazine

sodium hydroxide

→

N-tert-butyl-2-pyrazine-carboxamide

Solvents

water

Conditions

Workup

1. 1
   Otherat 40° C. or less
2. 2
   Otherat 9° to 15° C.
3. 3
   workup.WAITFurther, the temperature was kept at the same temperature for 2.5 hours
4. 4
   OtherAfter the reaction
5. 5
   Otherthe reaction liquid
6. 6
   workup.STIRRINGwith stirring
7. 7
   OtherPrecipitated crystalline solid was separated by filtration
8. 8
   Washwashed with water
9. 9
   Otherdried

Procedure

To 1030 g of an 80% aqueous solution of sulfuric acid (8.40 moles of sulfuric acid), 220.5 g (2.10 moles) of 2-cyanopyrazine was added dropwise keeping the internal temperature at 40° C. or less with stirring. In succession, 187 g (2.52 moles) of tert-butyl alcohol was added dropwise to the mixture, keeping the internal temperature at 9° to 15° C., over 3 hours. Further, the temperature was kept at the same temperature for 2.5 hours. After the reaction, the reaction liquid was added to 3500 g of water with stirring. Thus obtained mixture was neutralized with an aqueous solution of sodium hydroxide. Precipitated crystalline solid was separated by filtration, washed with water and then dried to obtain 338.7 g (1.89 moles) of N-tert-butyl-2-pyrazine-carboxamide. It had a melting point of 88° to 90° C. Further, from the water layer, from which the intended product had been separated by filtration, 7.17 g (0.04 mole) of the intended product was further obtained by extraction thereof with toluene.

Source