Piperazines were originally named because of their chemical similarity with piperidine, part of the structure of piperine in the black pepper plant (Piper nigrum). It is important to note, however, that piperazines are not derived from plants in the Pipergenus.
A form in which piperazine is commonly available industrially is as the hexahydrate, C4H10N2. 6H2O, which melts at 44°C and boils at 125-130°C.
Two common salts in the form of which piperazine is usually prepared for pharmaceutical or veterinary purposes are the citrate, 3C4H10N2.2C6H8O7 (i.e. containing 3 molecules of piperazine to 2 molecules of citric acid), and the adipate, C4H10N2.C6H10O4 (containing 1 molecule each of piperazine and adipic acid).
Piperazine was first introduced as an anthelmintic in 1953. A large number of piperazine compounds have anthelmintic action. Their mode of action is generally by paralysingparasites, which allows the host body to easily remove or expel the invading organism. The neuromuscular effects are thought to be caused by blocking acetylcholine at the myoneural junction. This action is mediated by its agonist effects upon the inhibitory GABA (γ-aminobutyric acid) receptor. Its selectivity for helminths is because vertebrates only use GABA in the CNS and the helminths' GABA receptor is a different isoform to the vertebrate's one. Piperazine hydrate and piperazine citrate are the main anthelmintic piperazines. These drugs are often referred to simply as "piperazine" which may cause confusion between the specific anthelmintic drugs and the entire class of piperazine-containing compounds.
Piperazines are also used in the manufacture of plastics, resins, pesticides, brake fluid and other industrial materials. Piperazines, especially BZP and TFMPP were extremely common adulterants in the club and rave scene, often being passed off as MDMA, although they do not share many similarities in their effects.
Piperazine is also a fluid used for CO2 and H2S scrubbing in association with methyl diethanolamine (MDEA).
Piperazine derivatives as drugs
Many currently notable drugs contain a piperazine ring as part of their molecular structure. Examples include: