替加环素代谢物M6 、 Isobutoxycarbonyl n-(tert-butyl)-n-(methoxycarbonyl)glycinate 生成 methyl 2-{[(5aR,6aS,7S,10aS)-9-(aminocarbonyl)-4,7-bis(dimethylamino)-1,8,10a,11-tetrahydroxy-10,12-dioxo-5,5a,6,6a,7,10,10a,12-octahydrotetracen-2-yl]amino}-2-oxoethyl(tert-butyl)carbamate