Unusual Anthracyclines

The anthracycline antibiotics have a tetracyclic ring structure attached to an unusual sugar, daunosamine. Cytotoxic agents of this class all have quinone and hydroquinone moieties on adjacent rings that permit the gain and loss of electrons. A number of important biochemical effects have been described for the anthracyclines and anthracenediones, all of which could contribute to their therapeutic and toxic effects. These compounds can intercalate with DNA, directly affecting transcription and replication. A more important action is the ability of these drugs to form a... 

Anthracyclines with free hydroxy groups in the 1,6,11-position are unknown so far they are related, however, to the unusual anthracyclines of the nogalarol and nogarol families, which differ strongly from the previous groups and are described separately in Unusual Anthracyclines (Sect. 3.12). 

The carbamates Garb-A (32g) and Carb-B (32h) [51] have been isolated from marine Streptomyces spp. isolates B9054 and B8904, respectively. Both contain the unusual glycocarbaminate fragment, which is typical for the bleomycin group but rare in other antibiotics. The only related anthracyclines are the monoglycosides rubomycin F (Fo 400) and H (Fo 399) [52]. 

A new cytotoxic antibiotic cytorhodin X from a Streptomyces strain has been shown to be an unusual anthracyclinone 9a-glycoside 6. Another new anthracycline antibiotic, dutomycin, also obtained from a Streptomyces strain, contains a disaccharide component 7 including the branched chain sugar L-axenose. ... 

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