Bolasterone

Bolasterone
Clinical data
Trade names	Myagen, Methosarb
Other names	U-19763; NSC-66233; 7α,17α-Dimethyltestosterone; 7α,17α-Dimethylandrost-4-en-17β-ol-3-one, Piratestosterone.
Routes of; administration	By mouth
Legal status
Legal status	BR: Class C5 (Anabolic steroids);
Identifiers
	IUPAC name (7R,8R,9S,10R,13S,14S,17S)-17-hydroxy-7,10,13,17-tetramethyl-2,6,7,8,9,11,12,14,15,16-decahydro-1H-cyclopenta[a]phenanthren-3-one;
CAS Number	1605-89-6 ;
PubChem CID	102146;
ChemSpider	92280;
UNII	T7ZM08F7FU;
ChEMBL	ChEMBL259548;
CompTox Dashboard (EPA)	DTXSID40166896 ;
ECHA InfoCard	100.015.018
Chemical and physical data
Formula	C21H32O2
Molar mass	316.485 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES O=C4\C=C3/[C@]([C@H]2CC[C@]1([C@@H](CC[C@@]1(O)C)[C@@H]2[C@H](C)C3)C)(C)CC4;
	InChI InChI=1S/C21H32O2/c1-13-11-14-12-15(22)5-8-19(14,2)16-6-9-20(3)17(18(13)16)7-10-21(20,4)23/h12-13,16-18,23H,5-11H2,1-4H3/t13-,16+,17+,18-,19+,20+,21+/m1/s1; Key:IVFYLRMMHVYGJH-VLOLGRDOSA-N;

Bolasterone (INNTooltip International Nonproprietary Name, USANTooltip United States Adopted Name) (brand names Myagen, Methosarb; former developmental code name U-19763), also known as 7α,17α-dimethyltestosterone, is a 17α-alkylated androgen/anabolic steroid (AAS) which is used in veterinary medicine.^[2]^[3] It has close structural similarity to testosterone, and like methyltestosterone has a methyl group at C17α in order to increase oral bioavailability.^[2] In addition, it is also 7α-methylated, similar to its 7β-methylated isomer calusterone.^[2] The medication has a low to moderate ratio of anabolic to androgenic activity, similar to that of fluoxymesterone.^[4]

Bolasterone is on the World Anti-Doping Agency's list of prohibited substances,^[5] and is therefore banned from use in most major sports.

Chemistry

The chemical synthesis was reported:^[6] Patent:^[7]

The oxidation of methyltestosterone [58-18-4] (1) with chloranil gives 17alpha-methyl-6,7-dehydrotestosterone [5585-85-3] (2). The conjugate addition of methylmagnesium bromide in the presence of a catalytic amount of cuprous iodide (c.f. Gilman reagent) gives a mixture of bolasterone and calusterone, with the former predominating.

^ Anvisa (2023-03-31). "RDC Nº 784 - Listas de Substâncias Entorpecentes, Psicotrópicas, Precursoras e Outras sob Controle Especial" [Collegiate Board Resolution No. 784 - Lists of Narcotic, Psychotropic, Precursor, and Other Substances under Special Control] (in Brazilian Portuguese). Diário Oficial da União (published 2023-04-04). Archived from the original on 2023-08-03. Retrieved 2023-08-15.
^ ^a ^b ^c Elks J (14 November 2014). The Dictionary of Drugs: Chemical Data: Chemical Data, Structures and Bibliographies. Springer. pp. 646–. ISBN 978-1-4757-2085-3.
^ Morton IK, Hall JS (6 December 2012). Concise Dictionary of Pharmacological Agents: Properties and Synonyms. Springer Science & Business Media. pp. 52–. ISBN 978-94-011-4439-1.
^ Kochakian CD (6 December 2012). Anabolic-Androgenic Steroids. Springer Science & Business Media. pp. 377, 401. ISBN 978-3-642-66353-6.
^ "The World Anti-Doping Code: The 2020 Prohibited List" (PDF). World Anti-Doping Agency. Retrieved 2019-12-28.
^ Campbell, J. A.; Babcock, J. C. (August 1959). "The Synthesis of Some 7α- and 7β-Methyl Steroid Hormones 1". Journal of the American Chemical Society. 81 (15): 4069–4074. doi:10.1021/ja01524a063. Retrieved 29 January 2026.
^ U.S. patent 3,341,557 Babcock, J. C.; Campbell, J. A.; Upjohn Co (1967).