In these studies, we had observed polyaniline (PANI) supported p-toluene sulfonic acid (TsOH) and FeCl3 (PANI- TsOH, PANI-FeCl3) as excellent reusable solid acid catalysts for the synthesis of 1, 8-dioxo-octahydroxanthene derivatives 4(a-g) under solvent-free grinding method at mild conditions. Additionally, in the same optimized condition ferric nitrate nonahydrate also acted as (non-reusable) very reactive inexpensive Lewis acid catalyst. The ferric nitrate nonahydrate lost its activity in the form of Clayfen (Clay-supported ferric nitrate) catalyst.

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.

Electron impact (EI) mass spectrometer apparatus has been used to monitor the relative intensities of ion clusters of the type Xn(H2O)n where X is 3-arylpyrimido[4,5-c]pyridazine-5,7(6H,8H)-diones (1a-d), 3-aryl-7-thioxo-7,8-dihydro-6H-pyrimido[4,5-c]pyridazine-5-ones (2a-d) and n = 1, 2. The m/z of selected fragments obtained from 1a-d and 2a-d show a clustered water molecule due to strong intermolecular H-bonding between fragment and clustered water molecule.

2-(5-Chloro-2-phenoxyphenyl)hydrazine was converted to corresponding 3H-indole by Fischer method utilizing the isopropyl methyl ketone in acetic acid. The reaction of 3H-indole with Vilsmeier-Haack reagent furnished aminomethylene malonaldehyde in excellent yield while the reactions of malonaldehyde with hydrazine, arylhydrazines, amines, cyanoacetamide and hydroxylamine hydrochloride, led to the corresponding pyrazole derivatives, enamines, cyanopyridone, and cyanoacetamide derivatives respectively.

An efficient, green, and facile four-component reaction for the preparation of pyrano[2,3-c]pyrazole derivatives through the condensation reaction of aryl aldehydes, ethyl acetoacetate, malononitrile, and hydrazine hydrate or phenyl hydrazine in the presence of commercially available organocatalyst sodium benzoate under aqueous condition is reported. The products are produced with high yields and in shorter reaction times. It also is mild, safe, green and environmental friendly.

The dicompartmental macrocyclic ligand (L2)2- was prepared by [1:1] cyclic condensation of N,N?-dimethyacetate-N,N?-ethylene-di(5-methyl-3-formyl-2-hydroxybenzylamine with 1,3-diaminopropane. The ligand includes dissimilar N(amine)2O2 and N(imine)2O2 coordination sites sharing two phenolic oxygen atoms and containing two methyl acetate pedant arms on the amine nitrogen donor atoms. A series of mono- and bimetallic complexes were synthesized and characterized on the basis of elemental analysis, molar conductance measurement, IR and UV-Vis spectroscopy techniques. It was found that during the cyclization process the copper (II) displaced from the N(amine)2O2 to the N(imine)2O2 coordination site and one of the methyl acetate pedant arms is dissociated. The heterodinuclear complex of [ZnL2Cu(?-OAc)]+ was prepared by a transmetallation reaction on the [ZnL2Zn(?-OAc)]+ by Cu(II). The characterization results showed that the two metal ions are bridged by two phenolic oxygen atoms and an acetate group, providing distorted five-coordination geometries for the both metal ions.

In the current work, beach sand (BS) and beach sand coated with polyaniline (BS/Pani) were used as an efficient green adsorbent for dye removal from aqueous solutions. Methylene blue (MB) was chosen as a test probe for the evaluation of the selected adsorbents for dye removal efficiency. The adsorption experiments were carried out in batch system and the effect of some important empirical parameters affecting adsorption processes were then investigated. The experimental data were also analyzed by Langmuir and Freundlich adsorption models. Based on the correlation coefficient values obtained (R2), it was found that equilibrium data for both adsorbents fitted well with both models. Adsorption data were also examined by pseudo-first-order and pseudo-second-order models and their respective rate constants were estimated. It was found that sorption of MB dye onto BS/Pani is fitted very well with pseudo-second-order kinetic model. Using the equilibrium concentration constants obtained at different temperatures, important thermodynamic parameters of the sorption process were calculated. It was found that the chemically modified beach sand is an effective and low cost adsorbent for dye removal from aqueous solutions.