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Quercetin is one of the most biologically active flavonols, and great attention has been paid for its detection in a variety of natural products over the few decades owing to its broad spectrum of applications. Herein, we have synthesized zinc oxide nanoparticles and carbon nanosheet separately, then the synthesized zinc oxide nanoparticles were dispersed uniformly into the carbon nanosheet, and finally, zinc oxide dispersed on carbon nanosheet modified carbon paste electrode (ZnO/CNS/MCPE) was fabricated. The prepared electrode is simple, highly sensitive, stable and cheaper for the detection of quercetin in standard solutions and real samples of onion and honey buckwheat. The scan rate optimization at ZnO/CNS/MCPE electrode showed electron-transfer co-efficient (α), electron-transfer number (n) and electrode reaction standard rate constants (Ks) as 1.13, 2.0 and 0.33 sec-1 respectively. The electrochemical response for quercetin detection with ZnO/CNS/MCPE was greatly enhanced, which is about 8.0 times higher than the unmodified carbon paste electrode. The limit of detection and limit of quantification values were found to be 0.04 and 0.13 μmol L-1 respectively. The relative standard deviation for the detection of 1.0 mmol L-1 quercetin in the standard solution for 10 successive cycles was found to be 1.76%. Compared to the other reported modified electrodes, the fabricated ZnO/CNS/MCPE has provided a superior electrochemical response, adequate selectivity and better sensitivity for the detection of quercetin in solution and real samples.

Currently, metallic nanoparticles possessing versatile heterogeneous catalytic functionality such as in hydrogenation, water splitting, hydrogen production and CO2 reduction for global pollution remediation have been paid great attentions due to their high chemical stability, superior activity and unique electrical and optical properties. However, the gradual degradation of their catalytic activity on multiple usage limits the monometallic nanoparticles to industrial applications. Herein, we fabricated the highly porous fenugreek polysaccharide assisted green synthesis of AuPd nanostructures for heterogeneous catalytic hydrogenation of the industrial usable highly toxic 4-nitrophenol to the medicinally useful 4-aminophenol. The aqueous method developed in the present work is environmentally friendly, simple and low-cost procedure. The fabricated bimetallic porous AuPd nanostructures characterized using SEM, TEM, UV-Vis, XRD, XPS and FTIR analysis. The catalytic activity of the synthesized nanostructures was studied for the heterogeneous hydrogenation of 4-nitrophenol to 4-aminophenol in presence of NaBH4, and the catalytic kinetic for the hydrogenation was analyzed via an UV-Vis spectrometer.

A new class of oxadiazoles is prepared by treating aminosulfonylacetic acids with different carboxylic acid hydrazides. Interconversion of oxadiazoles to thiadiazoles is carried out with thiourea. The compounds are screened for antimicrobial and antioxidant activities.

A new class of heterocycles, substituted pyrazoles, isoxazoles, pyrimidines, thioxopyrimidines were prepared from Michael adducts, 2-(1,2-diaroylethyl)malononitrile and 2-(1,2-diarylsulfonylethyl)malononitrile by cyclocondensation with appropriate nucleophiles. The lead compounds were screened for the antimicrobial and antioxidant activities.

A series of amine linked bis- and tris-heterocycles were prepared from heteroaryl cinnamamides and tested for antimicrobial activity. The compounds 11c and 12c exhibited excellent antibacterial activity while 12a and 12c displayed excellent antifungal activity.

12 Aminosulfonyl-1,3,4-oxadiazoles and the corresponding 1,3,4-thiadiazoles of type (III), (IV), (VI), and (VII) are screened for their antimicrobial and antioxidant activities.

The reactivity of ketene dithiolates in the presence of different equivalents of sodium ethoxide was studied. 2-(Bis((5-aryl-1,3,4-oxadiazol-2-yl)methylthio)methylene)malononitriles 5 and 2-(bis((5-aryl-1,3,4-thiadiazol-2-yl)methylthio)methylene)malononitriles 6 were prepared by the reaction of malononitrile with carbon disulfide and 5-aryl-2-(chloromethyl)-1,3,4-oxadiazoles 3/5-aryl-2-(chloromethyl)-1,3,4-thiadiazoles 4. The preliminary antimicrobial and antioxidant activities of the lead compounds were assayed.

Exploiting lanthanide chemistry and 1,3-dipolar cycloaddition technology, title compounds (V) are prepared as a new class of substituted pyrroles.

A new class of heterocycles, substituted pyrazoles, isoxazoles, pyrimidines, thioxopyrimidines were prepared from Michael adducts, 2-(1,2-diaroylethyl)malononitrile and 2-(1,2-diarylsulfonylethyl)malononitrile by cyclocondensation with appropriate nucleophiles. The lead compounds were screened for the antimicrobial and antioxidant activities.

A new class of sulfone linked pyrrolyl oxazolines and thiazolines were synthesized from E-arylsulfonylethenesulfonylacetic acid methyl ester and studied their antimicrobial and antioxidant activities.