Dealkylation 2.3.4- tris deriv

Inexpensive di-, tri-, and tetramethoxyanthraquinones can be selectively dealkylated to hydroxymethoxyanthraquinones by the formation of difluoroboron chelates with BF3-OEt2 in benzene and subsequent hydrolysis with methanol. These un-symmetrically functionalized anthraquinone derivatives are useful intermediates for the synthesis of adriamycin, an antitumor agent. 2,4,6-Tiimethoxytoluene reacts with cinnamic acid and BF3-OEt2, with selective demethylation, to form a boron heterocycle which can be hydrolyzed to the chalcone aurentiacin (eq 34). 2 ... 

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