Synthesis of Streptazoline Glucopyranosides

Abstract

The antibacterial properties of streptazoline (1),² isolated as a lipophilic neutral component from Streptomyces viridochromogenes,³ were recognized to be attributed to the formation of chartreusine.⁴ The pure compound 1 is rather labile due to the presence of the diene part, which enhances its polymerization. However, it may be kept for some time, in diluted solutions at low temperatures. Recently, the total synthesis of streptazoline (1) was reported,⁵ based on an azaanalogue Ferrier rearrangement.⁶ The catalytic hydrogenation of the compound 1 afforded the stable dihydrostreptazoline (4) which possessed lower antibacterial and antifungal activities than streptazoline (1) itself.⁷ X-ray studies of 5-acetoxydihydrostreptazoline (5) showed that it contained an internal urethane structure.