Azole C-Nucleosides

Azole C-nucleosides are among the most extensively studied C-nucleosides because of the many attempts directed toward the synthesis of showdomycin (4), the naturally occurring azole C-nucleoside antibiotic, as well as the synthesis of its analogs. Long before recognition of C-nucleosides, however, polyhydroxyalkyl pyrrole compounds (pyrrole acyclo C-nucleosides) were synthesized to study the reaction of amino sugars with 1,3-dicarbonyl compounds. 

The Naturally Occurring Azole C-Nucleoside Antibiotic Showdomycin and Its Congeners 

Showdomycin (4) was first isolated in 1964 by Nishimura [64JAN(A)148] from culture filtrates of Streptomyces showdoensis and then from other 

When introduced into cultures of Streptomyces NO. 383 or when treated with triethylamine, showdomycin (4) underwent a double bond shift to give 

Trummlitz and Moffatt prepared the tri-0-benzyl-/3-D-ribofuranosylgly-oxylic ester 45 from the 2,5-anhydro-o-allose derivative 54 and cyclized it 

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Like azole C-nucleosides (Section VI), 1,2-diazole C-nucleosides and their analogs were also extensively studied from both the academic and the applied and medicinal chemistry points of view after the discovery of the naturally occurring C-nucleoside antibiotic pyrazofurin (7). 

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