The megalomicins. Part IV. The structures of megalomicins A, B, C1, and C2
The elucidation of the structures and absolute stereochemistry of megalomicins A, B, C1, and C2, a group of macrolide antibiotics elaborated by Micromonospora megalomicea sp. n., is described. Megalomicin A has been shown to be (2R,3S,4S,5R,6R,8R,10R 11R,12S,13R)-3-(2,6-dideoxy-3-C-methyl-α-L-ribo-hexopyranosyloxy)-6,12-di-hydroxy-4,6,8,10,12-hexamethyl-9-oxo-11-(2,3,6-trideoxy-3-dimethylalmino-β-D-lyxo-hexopyranosyloxy)-5-(3,4,6-trideoxy-3-dimethylamino-β-D-xylo- hexopyranosyloxy)pentadecan-13-olide. Megalomicins B, C1, and C2 have been shown to be derivatives of megalomicin A acylated in the 3-glycosyl system.