1,1-cyclobutanedicarboxylic acid, diethyl ester 3779-29-1 InChI=1/C10H16O4/c1-3-13-8(11)10(6-5-7-10)9(12)14-4-2/h3-7H2,1-2H diethyl cyclobutane-1,1-dicarboxylate