Mycophenolate Mofetil EP Impurity E 

Chemical Name: methyl (4E)-6-(4-hydroxy-6-methoxy-7-methyl-3-oxo-1,3-dihydroisobenzofuran-5-yl)-4-methylhex-4-enoate (as per EP); Methyl (E)-6-(1,3-dihydro-4-hydroxy-6-methoxy-7-methyl-3-oxo-5-isobenzofuranyl)-4-methyl-4-hexenoate (as per USP)

Synonym: Methyl mycophenolate (USP) ; Mycophenolic acid methyl ester