AN EFFICIENT ONE-POT SYNTHESIS OF 1,4-DIACYL-2,3,5,6-TETRAMETHOXYBENZENES VIA BISCUPRATED PRECURSORS

The efficient double acylation of 1,2,4,5-tetramethoxybenzene via the corresponding dicopper species is described; this reaction could not b e attained either via the corresponding dilithium salts, or by Friedel -Crafts reaction. According to our method, the hitherto unknown diketo nes 1a and 1b are obtained in only one step in good yields. Further sy nthetic access to the compound 1a is realized by bismethylation of the corresponding terephthaloyl dichloride 7.