Piperidine

Piperidine is an organic compound with the molecular formula C5H11N. It is a heterocyclic amine with a six-membered ring containing five carbon atoms and one nitrogen atom. It is a clear liquid with a pepper-like odor.

The piperidine structural motif is present in numerous natural alkaloids such as piperine and quinine, and is the main active chemical agent in black pepper and relatives (Piper sp.), hence the name. Piperidine is also a structural element of many pharmaceutical drugs such as raloxifene, minoxidil, thioridazine and mesoridazine.

Piperidine is listed as a Table II precursor under the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances due to its use (peaking in the 1970s) in the clandestine manufacture of PCP (also known as angel dust).

Piperidine is often used as a solvent for its mild basic properties, most notably in Fmoc-strategy solid phase peptide synthesis.

The major industrial application of piperidine is for the production of dipiperidinyl dithium tetrasulfide, which is used as a rubber vulcanization accelerator.

Piperidine is naturally found in fire ant venom, and is the cause of the burning sensation associated with the bite of these insects.

Piperidine is also commonly used in chemical degradation reactions, such as the DNA sequencing method invented by Walter Gilbert in 1977, for cleavage of particular modified nucleotides. Piperidine is also commonly used as a strong base for the deprotection of amino acids in solid-phase peptide synthesis.

Use in pharmaceutical drugs
Many pharmaceutical drugs contain a piperidine ring because the group tends to impart pharmacokinetics such as water solubility and bioavailability. Examples of drugs that contain piperidines include mesoridazine, thioridazine, haloperidol, droperidol, PCP, benperidol, and risperidone.

Most piperidines induce the liver enzyme CYP2D6, resulting in faster metabolism of e.g. many beta-blockers and antiarrhythmics.