Studies on Macrocyclic Lactone Antibiotics. III. Skeletal Structure of Azalomycin F_4a

抄録

The skeletal structure of azalomycin F_4a (1) was determined on the basis of available data about the physicochemical properties of F_4a and about the structures of the degradation products of this compound and of its derivatives. The structure was found to consist of a 36-membered lactone ring bearing multiple hydroxy functions, a diene and a dienoic ester group, as well as a side chain with an N-methylguanidine moiety as its terminal. One of the hydroxyl groups on the lactone ring forms a hemiketal ring with the keto group on a ring carbon, and another hydroxyl group forms a hemiester with a malonic acid moiety.