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Abstract:
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The regiosomeric quinones 5-acetyloxymethyl-4,4,8-trimethyl- (5) and 8-acetyloxymethyl-4,4,5-trimethylanthracene-1,9,10(4H)-trione (6) were synthesized and their regiochemistry was assigned on the basis of the unambiguous structure elucidation of 9,10-dihydroxy-5-acetyloxymethyl-4,4,8-trimethyl-5,8-dihydroanthracen-1(4H)-one (2), the precursor of 5. The H-1 and C-13 NMR spectra of these compounds were assigned completely using two-dimensional techniques. These interpretations were used for the total assignment of the NMR spectra of the closely related 5-hydroxymethyl- and 5-formyl-4,4,8-trimethylanthracene-1,9,10(4H)-triones (7 and 8, respectively). |