(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-2-ethyl-3,4,10-trihydroxy-13-[(5-hydroxy-4-methoxy-4,6-dimethyl-3,4,5,6-tetrahydro-2H-pyran-2-yl)oxy]-11-({3-hydroxy-6-methyl-4-[methyl(nitroso)amino]-3,4,5,6-tetrahydro-2H-pyran-2-yl}oxy)-3,5,6,8,10,12,14-heptamethyl-6-aza-1-oxacyclopentadecan-15-one