Desosamine

Desosamine is a 3-(dimethylamino)-3,4,6-trideoxyhexose found in certain macrolide antibiotics (contain a high level of microbial resistance) such as the commonly prescribed erythromycin, azithromycin, clarithroymcin, methymycin, narbomycin, oleandomycin, picromycin and roxithromycin. As the name suggests, these macrolide antibiotics contain a macrolide or lactone ring and attached to the ring is desosamine which is crucial for bactericidal activity. Desosamine is a 3-(dimethylamino)-3,4,6-trideoxyhexose found in certain macrolide antibiotics (contain a high level of microbial resistance) such as the commonly prescribed erythromycin, azithromycin, clarithroymcin, methymycin, narbomycin, oleandomycin, picromycin and roxithromycin. As the name suggests, these macrolide antibiotics contain a macrolide or lactone ring and attached to the ring is desosamine which is crucial for bactericidal activity. Six enzymes are required for its biosynthesis from TDP-glucose in Streptomyces venezuelae. Desosamine serves as the sugar donor in this formation. Degradation of several of the aforementioned antibiotics yields the desosamine sugar. It is found in combination with the smaller macrolide rings, always attached at C-3 or C-5 of the aglycone. Alkaline degradation found the sugar to be a D-hexose derivative. Glycosidic cleavage of methomycin produces aglycone methynolide and the basic sugar desosamine, whose structure had been determined by oxidative degradation to crotonaldehyde and by other experiments.