Sulfuric Acid → N-tert-Butylpiperazine-2-carboxamide

Participants

Reaction Steps

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.

Provenance & Evidence