Labeled (R)-2-Methylbutyric Acid. (R)-2-Methylbutyric Acid is a metabolite of Ethyl (E)-2-methyl-2-butenoate (Ethyl tiglate), an important aroma compound in apples and serves as an indicator for genuineness of apple products due to its high optical purity of greater than 98% enantiomeric excess.Form:Light yellow oil