Synthesis and Biological Study of O-β-D-Glucosides of 7-Hydroxy-3-(Disubstituted Imidazol-2-yl)-4H-chromen-4-ones

A series of 7-o-beta-D-glucopyranosyloxy-3-(disubstituted imidazol-2-yl)-4H-chromen-4-ones 5 was synthesized. The 7-hydroxy-3-formyl-4H-chromen-4-one 1 reacted with various 1,2-dicarbonyl compounds 2 in the presence of ammonium acetate to furnish 7-hydroxy-3-(4,5-disubstitutedimidazol-2-yl)-4H-chromen-4-ones 3, which on glucosylation with alpha-acetobromoglucose affords 2,3,4,6-tetra-o-acetyl-7-o-beta-D-glucopyranosyloxy-3-(4,5-disubstituted imidazol-2-yl)-4H- chromen-4-ones 4. 7-o-beta-D-Glucopyranosyloxy-3-(4,5-disubstituted imidazol-2-yl)-4H-chromen-4-ones 5 were prepared by deacetylation with anhydrous zinc acetate in absolute methanol. Elemental analysis, IR, H-1 NMR, C-13 NMR, EI-MS spectral data were obtained to determine the structure of the newly synthesized compounds.