Quinolidomicins A1, A2 and B1, novel 60-membered macrolide antibiotics. II. Structure elucidation.

The structures of novel macrolide antibiotics, quinolidomicins A1, A2 and B1, were elucidated as shown in Fig. 1 by NMR spectral analysis including a variety of two-dimensional techniques. The quinolidomicins possess a novel 60-membered macrolide ring, which is to our knowledge the largest among natural products.