3-Methylanisole-d3 (m-Methoxytoluene-d3, m-MetHYlanisole-d3) is the deuterium labeled 3-Methylanisole (HY-115127)[1]. Methylanisole is a volatile metabolite produced by Penicillium strains growing on barley. 3-Methylanisole serves as a precursor for the biotechnological production of vanillin[1][2].