(4R,5S)-4-(2-Hydroxypropan-2-yl)-2,2,5-trimethyl-1,3-dioxolane-4-carboxylic Acid Methyl Ester-d6 is an intermediate in the synthesis of (+)-Echimidine-D3 , a labelled analogue of (+)-Echimidine (E325580), a hepatotoxic pyrolizidine alkaloid that is present in honey, pollen, and comfrey tea leaves.