Title: Fenethylline
CAS Registry Number: 3736-08-1
CAS Name: 3,7-Dihydro-1,3-dimethyl-7-[2-[(1-methyl-2-phenylethyl)amino]ethyl]-1H-purine-2,6-dione
Additional Names: 7-[2-[(a-methylphenethyl)amino]ethyl]theophylline; 7-[b-(a-methyl-b-phenylethylamino)ethyl]theophylline; 7-(phenylisopropylaminoethyl)theophylline; 7-(3-phenyl-2-propylaminoethyl)theophylline; theophyllineethylamphetamine
Molecular Formula: C18H23N5O2
Molecular Weight: 341.41
Percent Composition: C 63.32%, H 6.79%, N 20.51%, O 9.37%
Literature References: Prepn from 7-(b-chloroethyl)theophylline and amphetamine: Kholstaedt, Klinger, DE 1123329 (1962 to Degussa), C.A. 57, 5933c (1962). Metabolism in man: T. Ellison et al., Eur. J. Pharmacol. 13, 123 (1970).
Derivative Type: Hydrochloride
CAS Registry Number: 1892-80-4
Manufacturers' Codes: H-814
Trademarks: Captagon (Viatris)
Molecular Formula: C18H23N5O2.HCl
Molecular Weight: 377.87
Percent Composition: C 57.21%, H 6.40%, N 18.53%, O 8.47%, Cl 9.38%
Properties: Crystals, two different modifications, mp 227-229° and mp 237-239°.
Melting point: mp 227-229°; mp 237-239°
Derivative Type: d-Form hydrochloride
Properties: Crystals, mp 246-247°.
Melting point: mp 246-247°
Derivative Type: l-Form hydrochloride
Properties: Crystals, mp 246-247°.
Melting point: mp 246-247°
NOTE: This is a controlled substance (stimulant): 21 CFR, 1308.11.
Therap-Cat: CNS stimulant.
Keywords: CNS Stimulant.
Fenfluramine Fenhexamid Fenipentol Fennel Fenoldopam

Systematic (IUPAC) name
(RS)-1,3-dimethyl- 7-[2-(1-phenylpropan-2-ylamino)ethyl]purine- 2,6-dione
Clinical data
AHFS/Drugs.com International Drug Names
Legal status Schedule III (CA) Schedule I (US)
Routes Oral
CAS number 3736-08-1 N
ATC code N06BA10
PubChem CID 19527
DrugBank DB01482
ChemSpider 18398 YesY
KEGG D07944 YesY
Chemical data
Formula C18H23N5O2 
Mol. mass 341.408 g/mol
 N (what is this?)  (verify)

Fenethylline, also spelled phenethylline, is a synthetic prodrug used as a stimulant and marketed under the brand name Captagon.