Studies on Chemical Modification of Streptothricin-group Antibiotics. I. : On Citromycin Derivatives (Organic)

Citromycin (I) is converted into inactive citromycinic acid (II) by treatment with 3N hydrochloric acid and toxicity of II was less than one-half of that of I. Deformiminocitromycin (III) obtained by treatment with methanolic ammonia and deformiminocitromycin N-acetate (V) obtained by treatment with N-acetoxysuccinimide no longer had the original antibacterial activity. These facts indicate that antibacterial activity of citromycin requires the partial structure of (i) formation of a lactam ring in the streptolidine moiety and (ii) protection of the terminal amino group in glycine by a basic group like formimino, and that deformimination and N-acetylation results in the loss of its antibacterial activity.