N-(1-(4-Methoxyphenyl)propan-2-yl-d6)aniline Hydrobromide is the labeled analogue of N-(1-(4-Methoxyphenyl)propan-2-yl)aniline Hydrobromide(M265840), an impurity in the synthesis of Formoterol (F693400), a selective β2-adrenergic receptor agonist. Formoterol is used as an antiasthmatic.