2-[(2,6-Dichlorobenzyl)oxy]ethanol-d4 is an intermediate in the synthesis of Vilanterol Trifenatate-d4 (V260002). Vilanterol Trifenatate (V260000) is a long-acting β2 adrenergic receptor Agonist. It demonstrates prolonged bronchodilation in subjects with asthma and COPD.