Abstract
Although the migration pattern was dependent on the conditions of the reaction, a general path of acyl migration for O-myristoyl-D-glucoses and -glucosides could be identified as follows : (1) The well known O-1α→ -2 and O-4→ -6 migrations take place easily. Evidence for the reverse process (O-6→ -4) of the latter migration was obtained for O-myristoyl-D-glucosides. (2) For trans-migrations, the O-2→ -3 process was confirmed. It was apparently reversible for O-myristoyl-D-glucosides and also for O-myristoyl-D-glucose with pyridine. However, O-3→ -4 and O-1β→ -2 migrations were not observed. (3) O-3→ -6 Migration (through the 1C4 (D) conformation) was common for either O-myristoyl-D-glucoses or -glucosides. The reverse migration (O-6→ -3) was also observed, though to a small extent, for an O-myristoyl-α-D-glucoside. However, the O-2→-4 migration in an O-myristoyl-α-D-glucoside and -D-glucose was not observed, but instead the reverse O-4→ -2 process occurred, although only to a small extent. These results suggest that the migrations through the 1C4 (D) conformation occur much more readily for the α- than the β-D-anomer. (4) The O-myristoyl-1β group was rather stable to acyl migration. Upon heating in pyridine, the group migrated to O-3, and then to O-6. In contrast to the other O-myristoyl-D-glucoses, the O-myristoyl-1β derivative was solvolyzed to D-glucose and methyl myristate merely when kept in methanol solution.
