Matthias Wiesner

Preparations and reactions of acylated and partially acylated glycosyl fluorides

Abstract Partial acylation of glycosyl fluorides in the galacto (2 and 3) and gluco series (8–10) is readily achieved. Attempts to further alkylate these acyl derivatives failed. Treatment of 2 with Lewis acid, however, provided a facile route to the 1,4-anhydro derivative 5 . Lewis acid-mediated glycosylation of 2-acetamido-3,4,6-tri- O -acetyl-α- d -glucopyranosyl fluoride 11 led to the simple glycosides and thioglycosides 12–16 . Similarly, in the galacto series (17) an advantageous route to the β-galactosidase inhibitor 19 could be elaborated.

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.