
%0 Journal Article
%A Cameron, DW 
%A Feutrill, GI 
%A Mckay, PG 
%T Regiospecific synthesis of quinizarin and naphthazarin derivatives by cycloaddition
%J Australian Journal of Chemistry
%D 1982/10/01
%V 35
%N 10
%P 2095-2109
%K 
%R https://doi.org/10.1071/CH9822095
%U https://www.publish.csiro.au/paper/CH9822095 
%X The diene (E)-1,1,4-trimethoxybuta-1,3-diene underwent regiospecific cycloaddition to derivatives of 2(3)-chloro-1,4-naphthoquinone. The resulting adducts were aromatized to give 1,4-dioxygenated anthraquinones. The latter were obtained as derivatives of quinizarin dimethyl ether or of quinizarin monomethyl ether depending on the conditions of aromatization. Cycloaddition of the diene to non-halogenated naphthoquinones proceeded similarly, orientation being controlled by substituents in the benzenoid ring. Analogous reaction of the diene with benzoquinones gave 5,8-dioxygenated naphthoquinones (naphthazarins), generally in limited yield. The procedure has been applied to synthesis of the mould metabolites helminthosporin and cynodontin. 
