Greener route for microwave enhanced syntheses of bioactive 1,5-benzodiazepines using heterogeneous calcium ferrite/graphene oxide nanocomposite as a novel and sustainable catalyst

In the present paper, a novel and benign protocol for microwave enhanced one pot syntheses of 2,3-dihydro-1,5 benzodiazepine derivatives from substituted acetophenones, aryl-aldehydes and o-phenylene diamine using heterogeneous calcium ferrite/graphene oxide (CF/GO) nanocomposite has been reported. The catalyst was prepared by ultrasonication method and characterized by spectral and analytical techniques. The CF/GO nanocomposite was employed for environmentally benign synthesis of 2,3-dihydro-1,5 benzodiazepines. The synthesized benzodiazepine derivatives were screened for their antimicrobial activities against various bacteria and fungi. The present synthetic strategy offered several advantages such as excellent yields in short span of time, simple modus operandi, ease of isolation and purification of products, simple recovery and reusability of the catalyst. A tentative mechanism for synthesis of 2,3-dihydro-1,5 benzodiazepine using CF/GO nanocatalyst has also been proposed.     

Green synthesis and characterization of silver nanoparticles by Allium cepa L. to produce silver nano‐coated fabric and their antimicrobial evaluation

This research work was proposed to study the antimicrobial activity of the silver nanocoated fabric with the purpose of producing good dressing and clothing material. We synthesized simple, ecofriendly, cost‐effective and sustainable silver nanoparticles by using the aqueous extract of Allium cepa L. Here, A. cepa L. acts as a good reducing and capping agent that produced stable silver nanoparticles having particle size of range 36 ± 1 to 98 ± 2 nm, Poly dispersiblity index 0.234 ± 0.61 to 1.023 ± 0.33 and Zeta potential ‐12 ± 1.5 mV to ‐26 ± 1.2 mV. The effect of temperature and extract volume used was considered for optimization of synthetic procedure. The nanocoated fabric was characterized for morphological study, size (using transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE‐SEM) and zeta‐potential (Zeta Potentiometer). The presence of functional groups were observed by using attenuated total reflection‐Fourier transform infrared (ATR‐FTIR) and Raman spectroscopy. The crystallinity and structural property of the synthesized silver nanoparticles were studied in terms of Powder X‐ray diffraction (PXRD). An IC₅₀ value and zone of inhibition was studied which demonstrate that the silver nanocoated fabric have an excellent antibacterial property against Gram‐negative (Escherichia coli) and Gram‐positive (Staphylococcus aureus) bacteria. Further nanocoated fabric material was washed (with function of time 0, 10, 25, and 50 laundry cycles) and still retained their anti‐bacterial activity towards both strain. Initially there was 52 μg/ml of silver nanoparticles on the cotton fabric but after 50 laundry cycle in 500 ml of distilled water the fabric showed 92% efficiency against gram positive and 90% efficacy toward gram negative bacteria. It was found that 4.16 μg/ml nano particles leached in case of S. Aureus and 5.2 μg/mL silver nanoparticles leached in case of E. coli. Nanocoated fabric material synthesized using green synthesis was found to be economical with good resistance to washing.     

Water-Mediated Synthesis of Benzazole and Thiourea Motifs by Reacting Naturally Occurring Isothiocyanate with Amines

An efficient, green, and facile method has been developed for the synthesis of benzazole and thiourea analogues from naturally occurring erucin in moderate to good yields. The reaction was carried out in water without using any metal catalyst or base. The present method tolerated the various functional groups on aromatic rings and also applicable for other isothiocyanates.     

Base Catalysed Condensation of Acetone with Uracil Derivatives: One Step Synthesis of Pyranopyrimidines

Condensation of uracil derivatives (1,3,4) with acetone in the presence of triethylamine gave pyranopyrimidines (2,5,6).     

Determination of aliphatic amines by gas chromatography–mass spectrometry after in-syringe derivatization with pentafluorobenzoyl chloride

A simple and highly sensitive gas chromatographic method has been developed for the determination of low molecular weight short-chain aliphatic amines (SCAAs) after their simultaneous extraction and in-syringe derivatization with pentafluorobenzoyl chloride (PFBOC). Derivatization of the low molecular weight aliphatic amines in bicarbonate buffer of pH 10.5 with PFBOC was followed by immersed solvent microextraction. Derivatization conditions, including reagent concentration, reaction pH, ionic concentration of buffer, reaction time, stirring rate, reaction temperature and extraction solvent, have been investigated for method optimization. Linearity was studied within range of 0.15 pg ml⁻¹–50 ng ml⁻¹. The correlation coefficients were between 0.9934 and 0.9999. Detection limit of derivatized amines proved to be in the range of 0.117–1.527 pg ml⁻¹, and the intraday and interday relative standard deviation (RSD) values were less than 8% with respect to peak area. The method was applied for analysis of lake, river and industrial waste water. The recoveries of extraction from lake, river and industrial waste water samples, which have been spiked with different levels of aliphatic amines, were in the range of 68–99%, 63–102% and 62–105%, respectively.     

Synthesis, structural and electrical properties of La and Nb modified Bi4Ti3O12 ferroelectric ceramics

Polycrystalline ceramic samples of Bi_4−xLa_xTi₃O₁₂ (x=0.0, 0.5 and 1) and Bi_3.5La_0.5Ti_3−yNb_yO₁₂ (y=0.02 and 0.04) have been synthesized by standard high temperature solid state reaction method using high purity oxides and carbonates. The effect of lanthanum doping on Bi-site and Nb doping on Ti-site on the structural and electrical properties of Bi₄Ti₃O₁₂ powders was investigated by X-ray diffraction, scanning electron microscopy, dc conductivity and dielectric studies. A better agreement between the observed and calculated X-ray diffraction pattern was obtained by performing the Rietveld refinement with a structural model using the non-centrosymmetric space group Fmmm in all the cases. A better agreement between observed and calculated d-values also shows that the lattice parameters calculated using the Rietveld refinement analysis are better. The increase in lanthanum and niobium contents does not lead to any secondary phases. It is found that La³⁺ doping reduces the material grain size and changes its morphology from the plate-like form to a spherical staking like form. The substitution of Nb for Ti ions affected the degree of disorder and modified the dielectric properties leading to more resistive ceramic compounds. The shape and size of the grains are strongly influenced by the addition of niobium to the system. The activation energies of all the compounds were calculated by measuring their dc electrical conductivities. The frequency and temperature dependent dielectric behavior of all the compounds have also been studied and the results are discussed in detail. The substitution of La and Nb on the Bi and Ti sites decreased the T_c and improved the dielectric and ferroelectric behavior.     

Improved methods for the synthesis and isolation of imidazolium based ionic salts

Solvent-free reactions were used for the synthesis of a series of imidazolium-based ionic salts: 3,3′-[pyridine-2,6-diylbis(methylene)]bis(1-R-1H-imidazol-3-ium)chloride; (R = methyl, ethyl, butyl, isobutyl, hexyl, and benzyl). A simple and effective filtration process was used to isolate all the products in high purity and with yields ?93% within a 24 h period. The highly pure ionic compounds which are precursors to N-heterocyclic carbene ligands used in catalysis were fully characterized as gray-white hygroscopic salts.     

Two-echelon location routing synchronized with production schedules and time windows

Central European Journal of Operations Research - In this paper we study a problem that arose while planning the delivery of perishable goods, such as newspapers or foodstuff, in urban areas. The...