In the reaction of 3-bromothiophene with succinyl chloride in the presence of AlCl 3, a mixture of three isomeric dibromo-substituted 1, 4-di (2-thienyl) butane-1, 4-diones was formed. The main component was the unsymmetrical 1-(3-bromo-2-thienyl)-4-(4-bromo-2- thienyl) butane-1, 4-dione rather than 1, 4-di-(3-bromo-2-thienyl) butane-1, 4-dione expected according to the orientation rules.
