Enobosarm

Enobosarm ((2S)-3-(4-cyanophenoxy)-N-[4-cyano-3-(trifluoromethyl)phenyl]-2-hydroxy-2-methylpropanamide) (also known as ostarine, GTx-024, and MK-2866) is an investigational selective androgen receptor modulator (SARM) from GTX, Inc for treatment of conditions such as muscle wasting and osteoporosis, formerly under development by Merck & Company.

Structure

According to a recent paper authored by GTx, "Readers are cautioned to note that the name ostarine is often mistakenly linked to the chemical structure of [S-4], which is also known as andarine. The chemical structure of ostarine has not been publicly disclosed." While GTx has not formally disclosed the structure of ostarine, the chemical composition of ostarine is revealed in patent databases such the WIPO and discussed by Zhang et al., 2009 in the primary literature. Various SARM chemotypes exist (aryl propionamides, quinolines, quinolinones, bicyclic hydantoins), though aryl propionamides such as ostarine, andarine/S-4, and S-23 represent some of the most advanced putative therapeutics under investigation. In terms of atom connectivity, enobosarm differs from andarine by cyano substitutions on the phenyl rings as it replaces both the nitro and acetamido moieties.