(1alpha,2alpha,3alpha,4alpha)-2,4-bis(3,4-dihydroxyphenyl)-1,3-cyclobutanedicarboxylic acid dimethyl ester 1,3-cyclobutanedicarboxylic acid, 2,4-bis(3,4-dihydroxyphenyl)-, dimethyl ester, (1beta,2alpha,4alpha)- InChI=1/C20H20O8/c1-27-19(25)17-15(9-3-5-11(21)13(23)7-9)18(20(26)28-2)16(17)10-4-6-12(22)14(24)8-10/h3-8,15-18,21-24H,1-2H3/t15-,16+,17+,18 dimethyl (1s,2s,4s)-2,4-bis(3,4-dihydroxyphenyl)cyclobutane-1,3-dicarboxylate