Josamycin EP Impurity A

Chemical Name: (4R,5S,6S,7R,9R,10R,11E,13E,16R)-4-(Acetyloxy)-6-[[3,6-dideoxy-4-O-(2,6-dideoxy-4-O-butanoyl-3-C-methyl-α-L-ribo-hexopyranosyl)-3-(dimethylamino)-β-D-glucopyranosyl]oxy]-10-hydroxy-5-methoxy-9,16-dimethyl-7-(2-oxoethyl)oxacyclohexadeca-11,13-dien-2-one (as per EP)