DL-alpha-Methoxyphenylacetic acid is an organic compound, specifically a benzyl ether, also known as Trost's chiral acid. It appears as an off-white to light beige crystalline powder. It has the molecular formula C9H10O3 and a molecular weight of 166.18 g/mol. The CAS number for DL-alpha-Methoxyphenylacetic acid is 7021-09-2. It is also known by other synonyms like 2-methoxy-2-phenylacetic acid, MOPA, and MPA.