2-​Hydroxyethyl-d4 Benzoate is a labelled analogue of 2-​Hydroxyethyl Benzoate (E917525), a reagent that can be used as an intermediate in a variety of chemical and biochemical reactions. It is used as an intermediate in the preparation of 1,2-Ethanediol Disodium Salt (E890125), which is the result of the nucleophilic attack on its carbonyl group. It can be also used as an intermediate in synthesizing Acyclovir-d4, an orally active acyclic labelled nucleoside with inhibitory activity towards several herpes viruses. Antiviral.