APPROACHES TO THE REGIOSPECIFIC SYNTHESIS OF ANTHRACYCLINE ANTIBIOTICS

Article abstract of DOI:10.1016/0040-4020(82)80196-8

Synthetic approaches to anthracycline antibiotics were studied through the use of Claisen rearrangements on 1-methallyloxy-5-methoxyanthraquinone (9) which required reducing conditions to proceed through a hydroquinone intermediate in situ. 1-(2'-Methylene-4'-pentenoxy)-5-methoxyanthraquinone (13) underwent a similar reductive rearrangement but also produced a spiro compound 16 as a result of an ene reaction between the phenol and side chain double bond. 1-Hydroxy-2-methallyl-5-methoxyanthraquinone (11) could not be oxidized to quinizarin 17. 1-Hydroxy-2-methallyl-5,9,10-trimethoxyanthracene (21) was oxidatively coupled to the dimer at C-2.Dimer 23 reacted with diazomethane to form a 1,3-dipolar adduct 24.