(2R,3R,4R)-2,3,4-Trimethyl-2,3-(methylenedioxy)pentanedioic Acid is an intermediate in synthesizing Monocrotaline-d4 (M526002), a labelled Monocrotaline (M526000) which is a toxic pyrrolizidine alkaloid isolated from Crotalaria spp. It is used for inducing pulmonary diseases in rats.