Pentamethylene diamine (cadaverine), NH 2.
Braun (Ber., 1904, 37, p. 35 8 3) has prepared pentamethylene derivatives from piperidine by the action of phosphorus pentachloride.
On heating piperidine with phosphorus pentachloride to 200°C. in a sealed tube pentamethylene dichloride is obtained, and this on treatment with potassium phthalimide gives a condensation product of composition, C 6 H 4 [CO] 2 N(CH 2) 5 N[CO] 2 C 6 H 4, which is finally hydrolysed by hydrochloric acid.
Braun (Ber., 1904, 37, p. 2915) showed that benzoyl piperidine, when heated with phosphorus pentachloride to 200° C. in sealed tubes, yields benzonitrile, and pentamethylene dichloride, thus leading to a simple method of preparing pentamethylene compounds.