Dioxamycin, a new benz[a]anthraquinone antibiotic.

PD 116,779, a new antitumor antibiotic of the benz[a]anthraquinone class.

Total synthesis of (-)-8-O-methyltetrangomycin (MM 47755).

A stereoselective total synthesis of the natural antibiotic (-)-8-O-methyltetrangomycin 1 is reported. The essential steps for this convergent synthesis are the transformation of a geraniol epoxide into a chiral octadiyne derivative, which was converted into a triyne. The cobalt-mediated [2+2+2] cycloaddition of the triyne led to a benz[a]anthracene system, which was oxidized with Ag(Py)(2)MnO(...

Synthesis of the benz[a]anthraquinone core of angucyclinone antibiotics.

[reaction: see text] A general method for the synthesis of benz[a]anthraquinones is reported. The key step is a catalytic cobalt-mediated [2+2+2]-cycloaddition of a triyne, which affords an angularly substituted tetracycle. Oxidation of this core gives the typical structure of angucyclinone antibiotics.

Structures of the novel anthraquinone antitumor antibiotics, DC92-B and DC92-D.

The structures of the new anthraquinone antitumor antibiotic DC92-B and its photodegradation product DC92-D were determined by their spectral studies. DC92-B and D are pluramycin antibiotics, related to hedamycin which possess a characteristic ring F and a side chain containing a cis-epoxide and terminal dimethyl.

Efficient Synthesis of a Range of 1-Hydroxy-2-(1-Alkyloxymethyl)-9,10-Anthraquinone Derivatives

Five new 1-hydroxy-2-(1-alkyloxymethyl)-9,10-Anthraquinones (9a-e) have been prepared. Selective nitration of 2-methyl-9,10-anthraquinone, reduction to the corresponding amine, diazotization and treatment by sulfuric acid solution afforded the 1-hydroxy-2-methyl-9,10-anthraquinone in good yield as the key intermediate. Reaction with dimethylsulphate/K2CO3 and subsequen...