Title: Cyprenorphine
CAS Registry Number: 4406-22-8
CAS Name: (5a,7a)-17-(Cyclopropylmethyl)-4,5-epoxy-3-hydroxy-6-methoxy-a,a-dimethyl-6,14-ethenomorphinan-7-methanol
Additional Names: N-(cyclopropylmethyl)-7,8-dihydro-7a-(1-hydroxy-1-methylethyl)-O6-methyl-6,14-endo-ethenonormorphine; N-(cyclopropylmethyl)-6,14-endo-etheno-7a-(2-hydroxy-2-propyl)tetrahydronororipavine; N-(cyclopropylmethyl)-6,14-endo-ethenotetrahydronororipavine
Molecular Formula: C26H33NO4
Molecular Weight: 423.54
Percent Composition: C 73.73%, H 7.85%, N 3.31%, O 15.11%
Literature References: Narcotic antagonist closely related to diprenorphine, q.v. Prepn (7a- or 7b-linkage unspecified): BE 629070 (1963 to J. F. Macfarlan), C.A. 61, 13364g (1964); K. W. Bentley, US 3474101 (1969 to Reckitt & Sons); of 7a: K. W. Bentley, D. G. Hardy, J. Am. Chem. Soc. 89, 3281 (1967). Activity in rats: K. W. Bentley et al., Nature 206, 102 (1965). Use in large animals: M. R. Jainudeen, Vet. Rec. 89, 686 (1971); K. R. Presnell et al., J. Wildl. Dis. 9, 336 (1973). Binding to neuroleptic receptors: A. Czlonkowski et al., Life Sci. 22, 953 (1978). Determn by HPLC: I. Jane, A. McKinnon, J. Chromatogr. 323, 191 (1985).
Properties: Prisms from methanol, mp 234° (7a- or 7b-linkage unspecified).
Melting point: mp 234° (7a- or 7b-linkage unspecified)
Derivative Type: Hydrochloride
CAS Registry Number: 16550-22-4
Additional Names: M-285
Molecular Formula: C26H33NO4.HCl
Molecular Weight: 460.01
Percent Composition: C 67.89%, H 7.45%, N 3.04%, O 13.91%, Cl 7.71%
Properties: Crystals from methanol, mp 248°.
Melting point: mp 248°
NOTE: This is a controlled substance (opium derivative): 21 CFR, 1308.11.
Therap-Cat-Vet: Etorphine antagonist.
Cyproconazole Cyprodinil Cyproquinate Cyproterone Cyromazine

Cyprenorphine structure.svg
Systematic (IUPAC) name
6,7,8,14-tetrahydro- N-(Cyclopropylmethyl)- 7α-(1-hydroxy-1-methylethyl)- 6,14-endo-ethenonororipavine
Clinical data
Legal status Schedule I
CAS number 4406-22-8 YesY
ATC code None
PubChem CID 544534
ChemSpider 16735758 YesY
Chemical data
Formula C26H33NO4 
Mol. mass 423.545 g/mol
 YesY (what is this?)  (verify)

Cyprenorphine (M-285) is a drug which is an opioid derivative. It is related to more well-known opioids such as buprenorphine, which is used as an analgesic and for the treatment of opioid addiction, and diprenorphine, which is used as an antidote to reverse the effects of other opioids.

Cyprenorphine has mixed agonist–antagonist effects at opioid receptors, like those of buprenorphine. However the effects of cyprenorphine are somewhat different, as it produces pronounced dysphoric and hallucinogenic effects which limit its potential use as an analgesic.[1][2]