How is 1-Cyclopropylpiperazine dihydrochloride (CAS: 139256-79-4) typically synthesized?

1-Cyclopropylpiperazine dihydrochloride is commonly synthesized by the reaction of cyclopropylamine with piperazine followed by hydrochloric acid treatment. The reaction is carried out in an inert atmosphere, and the product is isolated by crystallization. The yield is typically around 70%, and the reaction is selective under the chosen conditions.