How is piperidin-4-amine dihydrochloride (CAS: 35621-01-3) typically synthesized?

Piperidin-4-amine dihydrochloride is typically synthesized by the reaction of piperidine with hydrochloric acid. The process involves the substitution of a hydroxyl group with a chlorine atom followed by neutralization with sodium hydroxide to form the amine, which is then reacted with hydrochloric acid to form the dihydrochloride salt. The yield is generally around 85-90%, and the reaction is carried out under mild conditions.