Hydroxy-esters syntheses from 4-HB and 3,4-DHB have been carried out by esterification with diols, such as EG, BDO and HDO, or a triol such as glycerol, to potentially increase polymer matrix compatibility, thermal stability, and antioxidant efficiency. Esterification and carbon chain addition is an increasingly common approach to the functionalization of phenolic antioxidants, as is the addition of primary aliphatic hydroxyl groups (Torres de . Proton NMR spectra of the corresponding products are available in Supplementary Information -SI -Figure to Figure .