5-[2-[(3-Chloro-2-hydroxypropyl)thio]-4-thiazolyl]-2-thiophenecarboxamide-d5 is an intermediate in synthesizing Arotinolol-D5 Hydrochloride (A771502), which is a labelled analogue of Arotinolol (A771500). Arotinolol is both and alpha- and beta-adrenoceptor antagonist and is used to treat essential tremors and hypertension.