Synthesis and biological activities of new hydroxy-3-pyrazolyl-4H-chromen-4-ones and their O-glucosides

1260-1270The synthesis of a number of 7-hydroxy-3-pyrazolyl-chromen-4H-ones and their O-glucosides has been described. 7-Hydoxy-3-formyl chromen-4H-one 1 on condensation with substituted acetophenones in the presence of piperidine in dry alcohol affords 7-hydroxy-3-(3-oxo-3-arylprop-1-enyl)-4H-chromen-4-ones 2 which on cyclization with phenyl hydrazine hydrochloride leads to the formation of 7-hydroxy-3-(1-phenyl-3-aryl-1H-pyrazol-5-yl)-4H-chromen-4-ones 3. 7-O-β-D-Glucopyranosyloxy-3-(1-phenyl-3-aryl-1H-pyrazol-5-yl)-4H-chromen-4-ones 5 have been synthesized by the reaction of 2, 3, 4, 6-tetra-O-acetyl-⍺-D-glucopyranosyl bromide with potassium salt of 3 followed by deacetylation with Zn(CH₃COO)₂ in absolute methanol. Some of the newly synthesized compounds have been screened for their antimicrobial and antioxidant activity