Abstract:
The Claisen rearrangement of 1,4-bis(2'- chloroprop-2'-enyloxy) anthraquinone in a variety of solvent systems and in the absence of a solvent has been investigated. The use of 13C n.m.r. in elucidating product structure is also reported.
The formation of a methyl ketone side chain at C-3 and the conversion of a furan ring into a formyl function at C-2 of the anthraquinone skeleton to give the acetal (97) are reported. The conversion of the acetal (97) to the anthracyclinone A-ring has been investigated.
The Claisen rearrangement of 1-hydroxy-4-(prop-2'- eny1oxy) anthraquinone in a variety of solvent systems has been examined, and the formation of (138) with o-dichlorobenzene as solvent confirms an earlier suggestion on the mechanism of an anomalous rearrangement of 1-hydroxy-4-allyloxy anthraquinones.