Clinical and Laboratory Observations of a New Antibiotic, Tetracycline

The chemical structures of chlortetracycline (Aureomycin)1and oxytetracycline (Terramycin)2have now been resolved after many months of chemical and biological studies. The close similarity in the chemical structures of these two antibiotics, which was revealed by these studies, had long been suspected on the basis of the almost identical spectrums of their antimicrobial activity and from the almost complete cross resistance between them.3Common to both of these antibiotics is the following structure:The name tetracycline has been proposed for this antibiotic. Chlortetracycline differs from oxytetracycline by the presence of one chlorine atom in the former that is absent from the latter and the presence of a hydroxyl group in oxytetracycline that is absent from chlortetracycline. The structures of these two antibiotics are as follows: The preparation of tetracycline by the catalytic hydrogenation of chlortetracycline, using palladium as a catalyst, was reported recently by workers of both