1,1-Dimethylethyl (R)-[2-[(methylsulfonyl)oxy]-1-phenylethyl]carbamate is a proposed intermediate in the synthesis of Elagolix-d6 Sodium Salt (E501016), which is the labelled analogue of Elagolix Sodium Salt (E501018), a novel uracil phenylethylamine that acts as potent human gonadotropin-releasing hormone receptor (hGnRH-R) antagonist.