SALMYCIN A-D, ANTIBIOTICS FROM STREPTOMYC ES-VIOLACEUS, DSM-8286, HAVING A SIDEROPHORE AMINOGLYCOSIDE STRUCTURE

Salmycin B (2) and C (3) were isolated under acid conditions, under wh ich they are stable, from the culture broth of Streptomyces violaceus, DSM 8286. The acid- and alkaline-labile, native main component salmyc in A (1), as well as salmycin D (4), were obtained under strictly neut ral pH conditions. The compounds 1 (C41H70FeN7O21), 2 (C41H69FeN6O21), 3 (C40H67FeN6O21), and 4 (C40H68FeN7O21) are classified as sideromyci ns and are stable when dry. Mild alkaline hydrolysis of 1 and 2 yielde d the known siderophor danoxamin (5; C27H46FeN5O11), and amino-disacch arides. The amino-glycoside 6 (C14H25NO11) of salmycin B was stabilize d by hydrogenation and the structure of the corresponding peracetate 1 0 determined by H-1,H-1- and (HC)-H-1-C-13-correlation NMR spectroscop y (Table 1). Compound 6 consists of a glucos-2-ulose unit which is lin ked to the 2-position of a 6-deoxy-6-(methylamino)heptopyranose. The d anoxamin is bonded via the carboxy group by ester linkage to the prima ry alcohol of the glucos-2-ulose. Salmycin A (1) is a natural oxime of 2, it was synthesized from 2 with hydroxylamine. The salmycins and th ose derivatives which contain hexapyranos-2-ulose form stable ketone h ydrates which can be identified by mass spectrometry. Although several recently identified features of the danomycins do not correspond with those of the salmycins, C-13-NMR spectra show that both groups of ant ibiotics are closely related. All salmycins, especially component 1, a re highly active against Staphylococci and Streptococci, even against resistant strains of these pathogens.