The structure, stereochemistry and reactions of the guanidine moiety of viomycin.

ment, together with a summary of the remarkable chemical reactivity of this unit. Ion exchange chromatography (Dowex 50Wx8) of the acid hydrolysate (10N hydrochloric acid, reflux for 24 hours) of viomycin afforded two basic amino acids, viomycidine and a small amount of a compound which we have termed viocidic acid. Viomycidine was characterised as its crystalline monohydrochloride m. p. 200~204°C and our spectral and chemical data were in accord with the structure II proposed by Buchi and Raleigh5). Viocidic acid was characterised as its dipicrate m.p. 173~175°C.