Synthesis and reactions of di(thiophen-2-yl)alkane diones: Cyclocondensation.

Known 1,6-di(thiophen-2-yl)hexane-1,6-dione ( 2 ) and novel 1,7-di(thiophen-2-yl)heptane-1,7-dione ( 4 ) were obtained from the reactions of thiophene with the corresponding diacyl chlorides. Furthermore, compounds with furan and pyrrole units in place of thiophene units in compound 2 were obtained in the same way. Bromination of 2 and 4 gave bromides regioselectively. The reaction of each of the compounds 2 and 4 in HOAc medium yielded cyclocondensation products. In total, four known and eleven novel compounds were synthesized.