Reaction #3744

Reaction equation

tert-butyl alcohol

sulfuric acid

2-cyanopyrazine

sodium hydroxide

→

N-tert-butyl-2-pyrazinecarboxamide

Solvents

water

Conditions

Workup

1. 1
   Otherat 40° C. or less
2. 2
   workup.WAITFurther, the temperature was kept at the same temperature for 2.5 hours
3. 3
   OtherAfter that, the reaction liquid
4. 4
   workup.STIRRINGwith stirring
5. 5
   OtherThe precipitated crystalline solid was separated by filtration
6. 6
   Washwashed with water
7. 7
   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 of which internal temperature was kept at 9° to 15° C. over 3 hours. Further, the temperature was kept at the same temperature for 2.5 hours. After that, the reaction liquid was poured into 3500 g of water with stirring. Thus obtained mixture was neutralized with an aqueous solution of sodium hydroxide. The precipitated crystalline solid was separated by filtration, washed with water and dried to obtain 338.7 g (1.89 moles) of N-tert-butyl-2-pyrazinecarboxamide. It had a melting point of 88° to 90° C. Further, from the filtrate 7.17 g (0.04 mole) of N-tert-butyl-2-pyrazine-carboxamide was further obtained by extraction thereof with toluene. The yield thereof was 91.9%.

Source