N-tert-butylpiperazine-2-carboxamide

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: In a reaction vessel were charged 343 g of water and 389 g (5.25 moles) of tert-butyl alcohol and then 219.5 g (1.05 moles) of 2-cyanopiperazine sulfate was dissolved in the mixture with stirring while keeping the temperature below 25° C. Then, while keeping the temperature at 25° C., to the solution was added dropwise 1372 g (8.4 moles) of an aqueous 80% sulfuric acid solution and further, the temperature of the mixture was kept at 40° C. for 3 hours to complete the reaction. Then, after cooling the reaction liquid to 25° C., 2700 g of tetrahydrofuran was added to the reaction liquid and the mixture was kept at a temperature of 0° C. for 3 hours. Precipitates were collected by filtration, dried, 241 g of the precipitates thus obtained was dissolved in 480 g of water and the solution was neutralized with an aqueous solution of 25% sodium hydroxide until pH thereof became 13. The solution was extracted thrice with one liter of chloroform, the extracts were combined with one another and chloroform was removed from the mixed extract under reduced pressure to provide 142 g (yield 73%) of N-tert-butyl-2-piperazine carboxamide. the temperature below 25° C at 25° C. the reaction Then, after cooling the reaction liquid to 25° C. the mixture was kept at a temperature of 0° C. for 3 hours Precipitates were collected by filtration dried 241 g of the precipitates thus obtained The solution was extracted thrice with one liter of chloroform was removed from the mixed extract under reduced pressure

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: In 1029 g (8.40 moles) of an aqueous 80% sulfuric acid was dissolved 219.5 g (1.05 mole) of 2-cyanopiperazine sulfate with stirring while keeping the temperature below 40° C. Then, while maintaining the temperature of from 9° C. to 15° C., to the solution was added dropwise 187 g (2.52 moles) of tert-butyl alcohol over a period of 3 hours and further, the mixture was kept at the same temperature for 2.5 hours to complete the reaction. Then, after adding 3 liters of water to the reaction liquid thus obtained, the mixture was neutralized with an aqueous solution of 25% sodium hydroxide until pH thereof became 10. Then, the reaction liquid was extracted twice with one liter of chloroform, the extracts were combined with each other, and chloroform was removed from the mixed extract under reduced pressure to provide 106.8 g (yield 55%) of N-tert-butyl-2-piperazine carboxamide having a melting point of from 151° C. to 152° C. the temperature below 40° C Then, while maintaining the temperature of from 9° C. to 15° C. the reaction to the reaction liquid thus obtained Then, the reaction liquid was extracted twice with one liter of chloroform was removed from the mixed extract under reduced pressure

Conditions: temp:0.00; pressure:0.00; stir: