87-91-2 InChI=1/C8H14O6/c1-3-13-7(11)5(9)6(10)8(12)14-4-2/h5-6,9-10H,3-4H2,1-2H butanedioic acid, 2,3-dihydroxy-, diethyl ester diethyl 2,3-dihydroxysuccinate