Title: Cyclorphan
CAS Registry Number: 4163-15-9
CAS Name: 17-(Cyclopropylmethyl)morphinan-3-ol
Additional Names: (-)-3-hydroxy-N-cyclopropylmethylmorphinan
Molecular Formula: C20H27NO
Molecular Weight: 297.43
Percent Composition: C 80.76%, H 9.15%, N 4.71%, O 5.38%
Literature References: Prepn: Gates, Montzka, J. Med. Chem. 7, 127 (1964); Gates, US 3285922 (1966 to Res. Corp.). Pharmacology: Harris et al., Arch. Int. Pharmacodyn. Ther. 165, 112 (1967).
Properties: Crystals from ethyl acetate, mp 187.5-189°. [a]D30 -120° (c = 2.26). LD50 in mice, rats (mg/kg): 24, 23 i.v. (Gates, 1966).
Melting point: mp 187.5-189°
Optical Rotation: [a]D30 -120° (c = 2.26)
Toxicity data: LD50 in mice, rats (mg/kg): 24, 23 i.v. (Gates, 1966)
Cycloserine Cyclosporins Cyclotheonamides Cyclothiazide Cyclovalone

Cyclorphan structure.svg
Systematic (IUPAC) name
Clinical data
Legal status  ?
CAS number 4163-15-9
ATC code  ?
PubChem CID 5359966
ChemSpider 4514407
Chemical data
Formula C20H27NO 
Mol. mass 297.434 g/mol

Cyclorphan is a hallucinogenic opioid mixed agonist–antagonist related to levorphanol discovered in the late 1960s. It is not marketed as an analgesic because of side effects related to its impact on the kappa opioid receptor,[1][2] but has found some use as a research chemical on and off since its discovery.