(R) - 1 - (1-naphthyl) ethylamine light yellow to brown transparent liquid, stable at normal temperature and pressure, air sensitive; Insoluble in acid, oxidant, anhydride, chloroformate, acyl chloride. It is an intermediate of sinacaset, which is used to treat secondary hyperparathyroidism in dialysis patients with chronic kidney disease (CKD) and hypercalcemia in patients with parathyroid carcinoma; Cinacacet intermediate.