A novel tetracyclic ring system. 10H-tetrazolo[5′,1′:3,4][1,2,4]triazino[5,6-b]indole

The reaction of 3-hydrazino-1,2,4-triazino[5,6-b]indole with nitrous acid affords a novel tetracyclic ring system: 10H-tetrazolo[5′,1′:3,4][1,2,4]triazino[5,6-b]indole. The mode of cyclization has been discussed.     

Analytical Extraction Methods and Sorbents’ Development for Simultaneous Determination of Organophosphorus Pesticides’ Residues in Food and Water Samples: A Review

Extensive use of organophosphorus pesticides in agriculture leads to adverse effects to the environment and human health. Sample preparation is compulsory to enrich target analytes prior to detection as they often exist at trace levels and this step is critical as it determines the concentration of pollutants present in samples. The selection of a suitable extraction method is of great importance. The analytical performance of the extraction methods is influenced by the selection of sorbents as sorbents play a vital role in the sensitivity and selectivity of an analytical method. To date, numerous sorbent materials have been developed to cater to the needs of selective and sensitive pesticides’ detection. Comprehensive details pertaining to extraction methods, developed sorbents, and analytical performance are provided. This review intended to provide a general overview on different extraction techniques and sorbents that have been developed in the last 10 years for organophosphorus pesticides’ determinations in food and water samples.     

Chemical Fixation of CO2 and Other Heterogeneous Catalytic Studies by Employing a Layered Cu‐Porphyrin Prepared Through Single‐Crystal to Single‐Crystal Exchange of a Zn Analogue

A solvothermal reaction of Zn(NO₃)₂ ? 6 H₂O, tetra‐(4‐pyridyl)porphyrin (H₂TPyP), and 4,4′‐oxybis(benzoic acid) (H₂OBA) resulted in a new two‐dimensional Zn‐ porphyrin metal–organic framework compound, [Zn₂(C₄₀H₂₄N₈)_0.5(C₁₄H₈O₅)(DMA)](DMA)(H₂O)₆ ( 1 ; DMA=N,N‐dimethylacetamide). The Zn^II ions present in 1 could be exchanged by using a solution of Cu(NO₃)₂ ? 3 H₂O in DMA at room temperature to give [Cu₂(C₄₀H₂₄N₈)_0.5(C₁₄H₈O₅)(DMA)](DMA)(H₂O)₃ ( Cu∈1 ). The extra‐framework solvent molecules have been shown to be reversibly removed or exchanged without collapse of the framework. Solvent‐free Cu∈1 was explored as an active heterogeneous catalyst towards three different organic reactions: 1) the chemical fixation of CO₂ into cyclic carbonate at room temperature and 1 atm; 2) the nitroaldol reaction under solvent‐free conditions, and 3) the three‐component coupling of aminopyridine, benzaldehyde, and aryl alkynes followed by 5‐exo‐dig cyclization to produce the important pharmacophore imidazopyridine.     

Methyl triphenylphosphonium permanganate as a novel oxidant for aniline to polyaniline-manganese(II,IV) oxide: material for high performance pseudocapacitor

In this work, organic-inorganic composite materials of polyaniline and manganese oxide were synthesized and investigated their electrochemical performance. This composite material was prepared by oxidizing aniline with methyl triphenylphosphonium permanganate as a novel organic oxidant via aqueous, emulsion, and interfacial polymerization pathways. This process led to the formation of polyaniline-sulfate salt (PANI-SA-Mn₅O₈). Formation of polyaniline-sulfate salt was confirmed from FT-IR, EDAX, and XRD results. Formation of Mn₅O₈ was supported by XRD spectrum. PANI-SA-Mn₅O₈ prepared via emulsion polymerization pathway was obtained in porous nanorod morphology with high conductivity (9.4 S cm^?1) compared to that of the other sample prepared via interfacial pathway (1.7 S cm^?1). Whereas, aqueous polymerization pathway resulted in sheet-like morphology with a conductivity of 0.8 S cm^?1. These composites were used as pseudocapacitive electrode materials. Electrochemical characterization (cyclic voltammetry, charge-discharge, and electrochemical impedance measurement) showed that composite prepared via emulsion polymerization pathway gave better electrochemical performance, and showed good cycling behavior.     

Highly efficient metal-free one-pot synthesis of α-aminophosphonates through reduction followed by Kabachnik–fields reaction using three-component system

One-pot synthesis of α-aminophosphonates directly from aryl nitro compounds, aldehydes/ketones, and diethyl phosphite using sodium dithionite through reduction and followed by Kabachnik–Fields reaction under metal-free conditions is reported. The major advantages are excellent yield, high chemoselectivity, neutral reaction medium, and simple experimental procedure. This methodology consists of the following steps: 1) amine formation from nitro compound, 2) imine formation from amine and aldehyde/ketone, 3) phosphate addition to imine.     

Synthesis and characterization of 4,4′‐dihydroxy‐α‐methylstilbene crystal

4,4′‐dihydroxy‐α‐methylstilbene (DHAMS) was synthesized by condensation reaction with chloroacetone and phenol in the presence of concentrated sulfuric acid, and has been successfully grown by solution growth technique. This is the first report in the literature on the crystallization of DHAMS and exhibited the birefringent melt (liquid crystal property) of the optical properties. FTIR and FTNMR studies are in accordance with the structure. Good quality crystals were grown by slow evaporation technique by acetone as solvent. A transmission spectrum of the crystal was obtained in the region of 285 nm. The structural and optical properties were studied. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

On the estimation of second moment for organic compounds in wide-line pmr: analysis of group geometry

Neutron diffraction data available in the literature have been analyzed statistically to arrive at the ideal geometry for the commonly occurring groups, NH ₄ ⁺ , NH ₃ ⁺ , CH₃, CH₂, and CH; this has yielded optimum experimental values for the bond length and bond angle parameters. They are: N-H distance of 1.030 Å in both NH ₄ ⁺ and NH ₃ ⁺ groups, H-N-H angle of 109.47° and 108.1° respectively in NH ₄ ⁺ and NH ₃ ⁺ and 110.8° for the corresponding X-N-H angle in –NH ₃ ⁺ . For CH₃, CH₂, and CH groups the bond length C-H is 1.090 Å, while the H-C-H and X-C-H angles are respectively 108.2° and 110.5° in CH₃ and 107.2° and 109.3° in CH₂. The importance of using precise values of both bond lengths and bond angles for the ideal geometry when estimating theoretical second moments is emphasized.Contribution No. 564 from the Department of Crystallography and Biophysics, University of Madras, Guindy Campus, Madras-600025, India.     

Synthesis and spectroscopic characterization of transition metal complexes derived from novel benzofuran hydrazone chelating ligand: DNA cleavage studies and antimicrobial activity with special emphasis on antituberculosis

Mononuclear divalent complexes of Co, Ni, Cu and Zn derived from a benzofuran‐based novel hydrazone tridentate ligand were synthesized and characterized using various spectroscopic methods. Elemental analysis reveals that the metal‐to‐ligand ratio is 1:2 which is supported by mass spectrometry results. Conductivity measurements suggest that all the complexes are non‐electrolytic in nature. The ligand and complexes were evaluated for their antimicrobial potency. Bioassay of all hydrazone chelates shows enhanced activity as compared to that of the ligand. The complex with cobalt ion as the metal centre shows better activity against fungi than the standard. Also, ligand and complexes were screened for antituberculosis activity; some analogues (Ni, Cu, Zn) are eight times more active than the standard. Both ligand and complexes show moderate ability to cleave calf thymus DNA. Copyright © 2015 John Wiley & Sons, Ltd.