Studies of the thermal N3 to N9 rearrangement of the 3-β-D-glucoside of the cytokinin, 6-benzylaminopurine

The initial observation of a rearrangement of the glucosyl residue from N 3 to N 9 during g.c.-m.s. of derivatives of the 3-β-D-glucosyl metabolite of 6-benzylaminopurine (1) has been further investigated by g.c., g.c.-m.s. and p.m.r. of the permethylated and perdeuteromethylated derivatives of (1). Results show that the major process is a thermal intramolecular 1, 3-shift of the glucosyl grouping to the 9-position with retention of configuration at the migrating centre, together with a smaller contribution from an intermolecular 1, 3-rearrangement which gives rise to both the 9-α- and 9-β-anomers. An ionic mechanism is proposed to explain both rearrangement processes.