The structures of the major
stable plant metabolites of the cytokinins zeatin and 6-benzylaminopurine have
been confirmed by synthesis to be 7- and 9-β-D-glucopyranosides. The small
quantities of metabolites initially isolated (< 100 μg)
precluded assignment of the glucose ring size or configuration of the anomeric
linkage so that synthesis of both the furanose and pyranose forms of
7-β-D- and 9-β-D-glucosylzeatin and 6-benzylaminopurine was
undertaken which allowed direct u.v., m.s. and t.l.c. comparison with the metabolites. Numerous synthetic
routes to the unusual 7-glucosides of the two cytokinins were explored, the
most successful utilizing a one-pot pyrimidine ring closure of an imidazole
derivative to afford directly in high yield the required 7-glucosides of zeatin
and 6-benzylaminopurine.
Nimesulide Based 1,2,4,5-Tetra Substituted Imidazole Derivative: Synthesis and Characterisation
