Uses and production of ?Piperazine

Piperazine is an organic compound that consists of a six-membered ring containing two opposing nitrogen atoms. First used as a solvent for uric acid, the use of piperazine as an anthelmintic agent was first introduced in 1953. Upon entry into the systemic circulation, the drug is partly oxidized and partly eliminated as an unchanged compound. Outside the body, piperazine has a remarkable power to dissolve uric acid and producing a soluble urate, but in clinical experience it has not proved equally successful. 

Chemistry

Piperazine is freely soluble in water and ethylene glycol, but insoluble in diethyl ether. It is a weak base with two pKb of 5.35 and 9.73 at 25 °C.; the pH of a 10% aqueous solution of piperazine is 10.8–11.8. Piperazine readily absorbs water and carbon dioxide from the air. Although many piperazine derivatives occur naturally, piperazine itself can be synthesized by reacting alcoholic ammonia with 1,2-dichloroethane, by the action of sodium and ethylene glycol on ethylene diamine hydrochloride, or by reduction of pyrazine with sodium in ethanol.

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).

Industrial production

Piperazine is formed as a co-product in the ammoniation of 1,2-dichloroethane or ethanolamine. These are the only routes to the chemical used commercially.The piperazine is separated from the product stream, which contains ethylenediamine, diethylenetriamine, and other related linear and cyclic chemicals of this type.

Mechanism of action

Piperazine is a GABA receptor agonist. Piperzine binds directly and selectively to muscle membrane GABA receptors, presumably causing hyperpolarization of nerve endings, resulting in flaccid paralysis of the worm. While the worm is paralyzed, it is dislodged from the intestinal lumen and expelled live from the body by normal intestinal peristalsis.

Uses

Piperazine can be used as alternative treatment for ascariasis caused by Ascaris lumbricoides (roundworm) and enterobiasis (oxyuriasis) caused by Enterobius vermicularis (pinworm). It is also used to treat partial intestinal obstruction by the common roundworm, a condition primarily occurring in children.

Piperazines are 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.