A simple and highly efficient procedure for synthesis of pyrazoles and O-Glucosides

Cyclization of 1-(3’-Methyl benzisoxazol-5’-yl)-3-phenyl prop-2-en-1-one 1a with hydrazine hydrate to produce 3-methyl-5-(3-phenyl-1H-pyrazol-5-yl)benzo[d]isoxazole 2a. Oxidation of compound 2a with KMnO₄ furnishes 5-(3’-Phenyl-1H-pyrazol-5’-yl)-1, 2benzisoxazole-3-carboxylic acid 3a. Glucosylation of 5-(3’-Phenyl-1H-pyrazol-5’-yl)-1, 2benzisoxazole-3-carboxylic acid 3a with 2, 3, 4, 6-tetra-O-acetyl-α-D-glucopyranosyl bromide (TAGBr) 4 to afford tetra-acetyl derivative 5a followed by deacetylation to give (2S, 3S, 4S, 5S)tetrahydro-3, 4, 5-trihydroxy-6-(hydroxymethyl)-2H-pyran-2-yl-5-(3-phenyl-1H-pyrazol-5yl)benzo[d]isoxazole-3-carboxylate 6a. The structures of the products have been assigned on the basis of FT-IR spectra, ¹H NMR, ¹³C NMR, FAB-MS, optical activity and elemental analysis. All the synthesized compounds were evaluated their antibacterial and antifungal activities by cup-plate method. The present approach offers several advantages such as shorter reaction times, cleaner reactions, good yields, inexpensive reagent and mild reaction conditions.