Compound 97

Compounds 99-109

In this series, (compounds 113 and 114; see pg. 323) lysinomicin (113) [109] and 2'-de-jV-l-lysyllysinomocin [110] showed good antibacterial activity against several strains. Fortimicin KG3 (114) and its related analogs are another branch of this family that have an unsaturated amino sugar moiety similar to that of sisomicins in their structure. Among these, fortimicin KG3 has potent antibacterial activity [111].

Another fortimicin analog is sporaricin E or 2-deoxy fortimicin B, which shows weak antibacterial activity [112]. In a report by Morioka et al. it was demonstrated that a blocked mutant of istamycin producing Streptomyces tenjimariensis converts fortimicin B to 1-epi-dactimicin with inversion of the amino group at position 1 and N-4-acylation [113].

Compounds 110 and 111

112 Sannamycin C Compound 112

113 Lysinomycin Compounds 113 and 114

B. Noncyclitol Aminoglycosides

The noncyclitol aminoglycosides include several monosaccharides, disaccharides, and those with the open-chain aglycon units. Compounds 115-117 (see pg. 324), nojirimycin (115) [114], streptozotocin (116) [115], prumycin (117) [116], and a few others are monosaccharides with only weak antibacterial activity.

Trehalosamines are representative of the disaccharides in this class of amino-glycosides and are relatively weak antibiotics. Trehalosamine (compound 118) [117], its 2-epimer mannosylglucosaminide [118], and the 4-amino derivative compound 119 [119] were isolated from culture filtrate of Streptomyces and showed weak an-

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