Aromatic aldehyde 4-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl)semicarbazones were synthesized by the addition of different hydrazones onto O-peracetylated β-d-glucopyranosyl isocyanate. Oxidative transformations of these precursors gave O-protected 2-(β-d-glucopyranosylamino)-5-substituted-1,3,4-oxadiazoles. Removal of the O-acetyl protecting groups under Zemplén conditions gave test compounds to show low micromolar inhibition against rabbit muscle glycogen phosphorylase b. Best inhibitors of these series were 4-(β-d-glucopyranosyl)semicarbazones of 4-nitrobenzaldehyde (Ki=4.5μM), 2-naphthaldehyde (Ki=5.5μM) and 2-(β-d-glucopyranosylamino)-5-(4-methylphenyl)-1,3,4-oxadiazole (Ki=12μM).
Keywords: 1,3,4-Oxadiazole; Glycogen phosphorylase; Inhibitor; Semicarbazone; β-d-Glucopyranosyl derivatives.
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