Vishwas Ingle

Synthesis of new series of 3-hydroxy/acetoxy-2-phenyl-4H-chromen-4-ones and their biological importance

Abstract3-Hydroxy-2-aryl/heteroaryl-4H-chromones 4(a–n) were synthesized from appropriate chalcones 3(a–n) and acetylated to afford the corresponding acetoxy derivatives 5(a–n). All compounds were evaluated for antimicrobial activity against Staphylococus aureus, Bacillus subtillis, Escherichia coli and Pseudomonas aeruginosa as well as fungi e.g., Candida albicans and Aspergius niger. Inhibition caused by hydroxy flavones was relatively low, whereas that of their acetoxy ester analogues was substantially high. Structure of 6-chloro-2-(furan-2-yl)-4-oxo-4H-chromen-3-yl acetate (5j) was also supported by means of single crystal X-ray diffraction. Graphical AbstractAn effective microwave-assisted synthesis of 3-acetoxy-2-aryl/heteroaryl-4Hchromones 5a-n has been achieved through a series of reactions starting from phenols. These compounds have been screened against gram (+) ve and (-) ve bacteria. The acetoxy flavones were biologically more active than the corresponding hydroxyflavones.

Synthesis of O‐β‐D‐Glucopyranosides of 7‐Hydroxy‐3‐(imidazol‐2‐yl)‐4H‐chromen‐4‐ones

The 7‐hydroxy‐3‐formyl‐4H‐chromen‐4‐one 1 reacted with various cyclic 1,2‐dicarbonyl compounds in the presence of ammonium acetate to furnish 7‐hydroxy‐3‐([4,5‐fused] imidazol‐2‐yl)‐4H‐chromen‐4‐ones 2a–f, which on glucosylation with α‐acetobromoglucose affords 2,3,4,6‐tetra‐O‐acetyl‐β‐D‐glucopyranosyloxy‐3‐([4,5‐fused] imidazol‐2‐yl)‐4H‐chromen‐4‐ones 3a–f. 7‐O‐β‐D‐Glucopyranosyloxy‐3‐([4,5‐fused] imidazol‐2‐yl)‐4H‐chromen‐4‐ones 4a–f were prepared by deacetylation with anhydrous zinc acetate in absolute methanol. The structure of these new O‐β‐D‐glucosides was established on the basis of chemical, elemental, and spectral analysis. These compounds were evaluated for their in vitro biological activity.

Synthesis, antibacterial screening, and POM analyses of novel bis-isoxazolyl/pyrazolyl-1,3-diols

This research article reports the synthesis of 4,6-bis(5-aryl/heteroaryl-1,2-oxazol-3-yl)benzene-1,3-diol 4a–4f and 4,6-bis(5-aryl/heteroaryl-1H-pyrazol-3-yl)benzene-1,3-diol 5a–5f from 1,1′-(4,6-dihydroxybenzene-1,3-diyl)bis(3-aryl/heteroarylpropane-1,3-dione) 3a–3f. The compounds were fully characterized using spectroscopic analyses and tested for their antibacterial activity. A correlation of structure and activities relationship of these compounds with respect to molecular modeling, Lipinski rule of five, drug likeness, toxicity profiles, and other physico-chemical properties of drugs are described and verified experimentally.Graphical AbstractThis article reports the synthesis of bis-isoxazoles 4a–4f and bis-pyrazoles 5a–5f. A good correlation of structure and activities relationship of these compounds with respect to molecular modeling, Lipinski rule of five, drug likeness, toxicity profiles and other physico-chemical properties of drugs are described and verified experimentally.

Synthesis of 2-(Substituted Benzylideneamino)-4-(4′-hydroxyphenyl) Thiazoles and Their O-Glucosides

2-Amino-4-(4′-hydroxyphenyl) thiazole 1a was prepared from reaction between p-hydroxyacetophenone, thiourea, and iodine; compound 1a was treated with several (aryl/hetro aryl) aldehydes to form 2-(substituted benzylideneamino)-4-(4′-hydroxyphenyl) thiazoles 2a–j, which were glucosylated by using acetobromoglucose as a glucosyl donor to afford 2-(substituted benzylideneamino)-4-(2, 3, 4, 6-tetera-o-acetyl-4′-o-β-d-glucosidoxyphenyl) thiazoles 3a–j, which further on during deacetylation produced 2-(substituted benzylideneamino)-4-(4′-o-β-d-glucosidoxyphenyl) thiazoles 4a–j. These compounds were evaluated for biological activity, and their structure was confirmed by IR, NMR, mass spectra, elemental, and chemical analysis.

Oxovanadium (IV) complexes of 2-aryl/heteroaryl-3-hydroxy-4H-chromones: synthesis, spectral and thermal degradation studies

The clinically active functionalized flavonols (2-aryl/heteroaryl-3-hydroxy-4H-chromones) (4a-l) have been synthesized from Algar–Flynn–Oyamada transformation of chalcones (1-(2-hydroxyphenyl)-3-phenylprop-2-en-1-ones). Their oxovanadium metal complexes (5a-l) have been prepared and characterized by physical, spectral, thermal and analytical data. The functionalized flavonol acts as bidentate ligand and coordinates with vanadium metal atom through hydroxyl and carbonyl groups. The complexes have general formula [MOL2], where M = vanadium, O = oxygen and L = ligand. The chelation process reduces the polarity of metal ion by coordinating with ligands, which increase the lipophilic nature of the metals. This lipophilic nature of the metal enhanced its penetration through the lipoid layer of cell membrane of the micro-organism. This constitutes a new group of compounds that can be used as potential metal-derived drugs.

Antimicrobial/antioxidant activity and POM analyses of novel 7-o-β-d-glucopyranosyloxy-3-(4,5-disubstituted imidazol-2-yl)-4H-chromen-4-ones

A series of 7-o-β-d-glucopyranosyloxy-3-(4,5-disubstituted imidazol-2-yl)-4H-chromen-4-ones 4 were synthesized and tested for in vitro antibacterial/antifungal and antioxidant activity. The synthesized compounds o-β-d-glucoside of 7-hydroxyl-3-imidazolyl-4H-chromen-4-ones showed good antibacterial/antifungal activity as well as antioxidant activity. The results suggest that aglycone as well as their o-glucosides could be promising candidates for new combined antifungal/antibacterial as well as antioxidant agents (3 in 1). Experimental data and Petra/Osiris/Molinspiration (POM) analyses, respectively, show high bioactivity against various microorganisms at a very low concentration without any side effect, suggesting that series 2–4 is a potential antimicrobial inhibitor and further it deserves to be validated for in vivo studies.Graphical Abstract7-Hydroxy-3-(4,5-disubstituted imidazol-2-yl)-4H-chromen-4-ones and their o-β-d-glucosides were synthesized and evaluated for in vitro antimicrobial and antioxidant activity. The compounds were also subjected to high-throughput POM bioinformatics to study the bioavailability.