Chemical Studies on Blasticidin S Part III

The Structure of Blasticidin S

Abstract

Blasticidin S was cleaved into cytosinine and blastidic acid by acid hydrolysis under selected condition. Chemical and NMR spectral evidences showed that blastidic acid has the structure VI. Alkaline hydrolysis of blasticidin S gave cytomycin which was further degradated into cytosinine and blastidone, whose structure was assigned as 4-ureido-N-methylpiperidone. Hydrogenolyses of blasticidin S and cytomycin afforded the hydro-genolytic compounds SC₁₃ and C₁₃ respectively. SC₁₃ was transformed into C₁₃ by alkali, which was further degradated via partial hydrolysis product PHC₁₃ into 3-aminotetra-hydropyran-2-carboxylic acid and blastidone. The sequence of these reactions established clearily the relationship of degradative compounds and provided evidences to assign struc-ture I and II to blasticidin S and cytomycin respectively.