Benzoic acid, 4-methoxy-,(1R)-3-azido-1-[[(4R,6S)-6-[[(4R,6S)-6-[(2S)-4-(2,2-dimethyl-1-oxopropoxy)-2-[(4-methoxybenzoyl)oxy]butyl]-2,2-dimethyl-1,3-dioxan-4-yl]methyl]-2,2-dimethyl-1,3-dioxan-4-yl]methyl]propyl ester