2H-IMidazole-2-thione, 5-(aMinoMethyl)-1-[(2R)-5,7-difluoro-1,2,3,4-tetrahydro-2-naphthalenyl]-1,3-dihydro-,

(R)-Nepicastat Hydrochloride is the R-enantiomer of Nepicastat Hydrochloride; a novel, potent, selective, and orally active inhibitor of dopamine-β-hydroxylase. The R-enantiomer was shown to be approximately 2-3 times less potent than Nepicastat Hydrochloride.