Oripavine (OPV)

Oripavine is an opiate and the major metabolite of thebaine. It is the parent compound from which a series of semi-synthetic opioids are derived, which includes the compounds etorphine and buprenorphine. Although its analgesic potency is comparable to morphine, it is not used clinically due to its severe toxicity and low therapeutic index. Oripavine possesses an analgesic potency comparable to morphine; however, it is not clinically useful due to severe toxicity and low therapeutic index. Oripavine has a potential for dependence which is significantly greater than that of thebaine but slightly less than that of morphine. Of much greater relevance are the properties of the orvinols, a large family of semi-synthetic oripavine derivatives classically synthesised by the Diels-Alder reaction of thebaine with an appropriate dienophile followed by 3-O-demethylation to the corresponding bridged oripavine.