PCP: a review of synthetic methods for forensic clandestine investigation.

A review of the synthetic routes to phencyclidine (PCP, 1-(1-phenylcyclohexyl)piperidine) available in the open literature is presented. The emphasis herein is directed toward the forensic investigation of clandestine PCP laboratories. Six published synthetic routes to PCP/analogs are discussed. Each method is rated for overall yield, degree of difficulty and potential hazard, in order to assist the forensic chemist in evaluation of a particular clandestine operation. One clandestine recipe is illustrated and discussed.