An ecofriendly methods for the synthesis of medicinally important class of heterocyclic scaffold, pyrazole 4-carbonitrile derivatives by one pot three component reaction of malononitrile, phenyl hydrazine and aromatic aldehyde has been achieved at room temperature. Greener protocols of reaction are followed by using sodium chloride to accelerate the reaction in aqueous media. Present methodology is a condition based divergence on synthesis of pyrazole by using simple salts, which offers several advantages like use of aqueous media and high yield of product along with short reaction time, simple work up procedure, no waste or by products, avoid the use of heavy metals or nanoparticles are the fascinating characteristics of reaction.

A series of new Schiff bases of 4-(methylthio)benzaldehyde derivatives 3(a-i) were synthesized by the reaction of 4-(methylthio)benzaldehyde with various amines 2(a-i). Newly synthesized compounds were characterized by elemental analyses, UV-visible, FT-IR, Mass and 1H NMR spectral studies. All compounds were evaluated for their in vitro antibacterial activity against clinically isolated strains i.e., E. Coli, P. Fluorescence, M. Luteus and B. Subtilis. These compounds were screened for their antioxidant activity by 2,2-diphenyl-1-picryl-hydrazyl (DPPH•) and ferrous ion chelating assay (Fe2+) methods. The cytotoxicity assay was performed by tryphan blue dye exclusion method. Compounds 3g, 3h and 3i exhibited good antibacterial activity when compared with other compounds in the series against tested pathogenic bacterial strains. All the compounds showed antioxidant activity, where compound 3b was the best radical scavenger and Fe2+ ion scavenger. These findings showed that the Schiff bases of 4-(methylthio)benzaldehyde derivatives possess antioxidant activity with different mechanism of actions towards the different free radicals tested. Among these derivatives, 3b and 3h had the strongest activity against human peripheral lymphocytes.

A series of some new (E)-2-(arylbenzylidene)-2-((4-methoxyphenyl)amino)acetohydrazides 4(a-j) have been conveniently synthesized by intermolecular oxidative cyclization of (E)-2-(arylbenzylidene)-2-[(4-methoxyphenyl)amino]acetohydrazides promoted by iodobenzene diacetate as an oxidant. The structures of the synthesized compounds have been confirmed by 1H NMR, IR, MS and elemental analysis. All the synthesized compounds were tested for their inhibitory action against clinically isolated strains i.e., Bacillus subtilis, Staphylococcus aureus, Xanthomonas campestris, Escherichia coli and Fusarium oxysporum. Compounds 4f (21-28 mm, 73.8 %), 4i (20-24 mm, 72.4 %) and 4j (21-27 mm, 71.6 %) demonstrated good antimicrobial activity against all the tested bacterial and fungal strains.