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An eco-efficient and economic method was proposed for the synthesis of different chromenoquinoline-10,12(6H)-dione derivatives via mortar-pestle grinding. This synthetic approach uses a mixture of substituted arylaldehyde, cyclohexane-1,3-dione and 2-amino-4H-chromen-4-one in the presence of environmentally friendly [Et3NH][HSO4]. This approach encompasses a one-pot, three-component synthesis process that employs mortar-pestle grinding. It has several benefits, such as being cost-effective, easy to handle, and short reaction time (30 min). The reaction can be carried out at ambient temperature, and the purification process is short and simple, resulting in excellent yield (70–93%). 1H, 13C NMR, FT-IR, MS analytical data were used for identification of synthesized derivatives. Furthermore, the method is environmentally friendly since it eliminates toxic solvents, column chromatography, and metal catalysts. The constructed 3,5-dichloro and 4-fluoro substituted chromenoquinoline-10,12(6H)-diones showed a good result against the chosen protein. [ABSTRACT FROM AUTHOR]

Ultrasound assisted, sulfated tin oxide SO42–/SnO2 (STO) catalyzed multicomponent reaction was used for the construction of a biologically valuable 1,2,4,5-tetraaryl imidazole derivatives. This sustainable technique has many advantages like green approach, inexpensive, comfortable set up, quick results, ecofriendly reagents, and easy isolation. The computational study of the synthesized compounds was performed against 1O75 protein of syphilis bacteria. [ABSTRACT FROM AUTHOR]

Skeletal materials belonging to the defect pyrochlore family have been the subject of considerable interest due to their remarkable properties. In this work, a highly efficient, stable and visible light active composite photocatalytic system consisting of defect pyrochlore of composition KMn0·33Te1·67O6 (KMnTeO) and g-C3N4 (g-CN) has been successfully prepared by simple physical mixing of pre-prepared KMnTeO and g-CN components synthesized in solid state and thermal treatment of low-cost melamine, respectively. Structural, morphological and optical properties of as-prepared catalysts were deduced from powder X-ray Diffraction (XRD), Fourier Transform Infrared (FT-IR), Raman, Field Emission Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (FESEM-EDX), Transmission Electron Microscopy-High Resolution Transmission Electron Microscopy (TEM-HRTEM), Ultraviolet–Visible Diffuse Reflectance Spectroscopy (UV–Vis DRS), X-ray Photoelectron Spectroscopy (XPS) and Photoluminescence (PL) measurements. The lattice parameter “a” of parent KMnTeO was obtained from Rietveld refinement of its powder XRD pattern. The FT-IR and Raman spectra of KMnTeO gave characteristic bands belonging to the defect pyrochlore structure. The photocatalytic activities of KMnTeO and composite KMnTeO-g-CN were evaluated by the degradation of methylene blue (MB). Scavenger experiments were carried out to identify the reactive species responsible for the degradation of MB. Furthermore, the reusability and stability of the photocatalysts were explored. The probable photocatalytic mechanism for MB degradation over the composite KMnTeO-g-CN was surmised according to the scavenger experiments. The work provides a new approach for the development of novel defect pyrochlore based composite photocatalysts to treat industrial wastewater containing organic pollutants.

The uranyl ion (UO 2 ) 2+ , a uranium nuclear waste, is one of the serious contaminants in our ecosystem because of its radioactivity, relevant human activities, and highly mobile and complex nature of living cells. In this article, we have reported the synthesis and structural characterization of an uranyl cation-incorporated polyoxometalate (POM) compound, K 10 [{K 4 (H 2 O) 6 }{UO 2 } 2 (α-PW 9 O 34 ) 2 ]·13H 2 O ( 1 ), in which the uranyl cations are complexed with an in situ generated [α-PW 9 O 34 ] 9- cluster. Single-crystal X-ray diffraction (SCXRD) analysis of compound 1 reveals that the uranyl-potassium complex cationic species, [{K 4 (H 2 O) 6 }{UO 2 } 2 ] 8+ , is sandwiched by two [α-PW 9 O 34 ] 9- clusters resulting in a Dawson type of POM. Compound 1 was further characterized by inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis and infrared (IR), Raman, electronic absorption, and solid-state photoluminescence spectral studies. IR stretching vibrations at 895 and 856 cm -1 and the Raman signature peak at 792 cm -1 in the IR and Raman spectra of compound 1 primarily confirm the presence of a trans -[O═U═O] 2+ ion. The solid-state photoluminescence spectrum of 1 exhibits a typical vibronic structure, resulting from symmetrical vibrations of [O═U═O] 2+ bands, corresponding to the electronic transitions of S 11 → S 10 and S 10 → S 0 υ (υ = 0-3). Interestingly, title compound 1 shows efficient electrocatalytic hydrogen evolution by water reduction with low Tafel slope values of 186.59 and 114.83 mV dec -1 at 1 mA cm -2 along with optimal Faradaic efficiency values of 82 and 87% at neutral pH and in acidic pH 3, respectively. Detailed electrochemical analyses reveal that the catalytic hydrogen evolution reaction (HER) activity mediated by compound 1 is associated with the U VI /U V redox couple of the POM. The microscopic as well as routine spectral analyses of postelectrode samples and controlled experiments have confirmed that compound 1 behaves like a true molecular electrocatalyst for the HER. To our knowledge, this is the first paradigm of a uranium-containing polyoxometalate that exhibits electrocatalytic water reduction to molecular H 2 . In a nutshell, an environmental toxin (a uranium-oxo compound) has been demonstrated to be utilized as an efficient electrocatalyst for hydrogen generation from water, a green approach of sustainable energy production.

A simple, precise, and rapid stability-indicating reversed-phase-HPLC method was developed and validated for the estimation of metformin (MET), dapagliflozin (DAP), and saxagliptin (SAX) combination in bulk and tablet dosage forms. The proposed method uses a Kromasil C18 column (150 × 4.6 mm, 5 μm) with column oven temperature of 30°C and mobile phase containing a mixture of 60% phosphate buffer (pH = 3) and 40% acetonitrile. The flow rate was set at 1.0 mL/min, and the injection volume was 10 μL. The detection was carried out at 230 nm using a photodiode array detector, and the total run time was 4 min. The proposed method was validated according to International Council for Harmonisation (ICH) guidelines for specificity, linearity, precision, accuracy, robustness, and solution stability. The method is linear over the range of 125-750 μg/mL for MET, 1.25-7.5 μg/mL for DAP, and 0.625-3.75 μg/mL for SAX. The observed correlation coefficients (R 2 ) for MET, DAP, and SAX are >0.999. The proposed method is precise, and the percentage relative standard deviation was found to be between 0.4 and 0.8. The observed percentage recoveries were between 98.51 and 100.80 for all three compounds. The product was subjected to stress conditions of acid, base, oxidative, thermal, and photolytic degradation. The product was found to degrade significantly in oxidative, acid, and base hydrolysis degradation conditions, and the degradation products were well determined from the active peaks, thus proving the stability-indicating power of the method. The developed and validated stability-indicating reversed-phase-HPLC method was appropriate for quantitative determination of these drugs in pharmaceutical preparations and also for quality control in bulk manufacturing., (© 2022 John Wiley & Sons Ltd.)

A reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the identification and quantification of moxifloxacin hydrochloride-related substances in finished dosage forms. Chromatographic separation was achieved on an Agilent C18 column (150 × 4.6 mm, 5 μm) with the mobile phase (0.01 M potassium dihydrogen orthophosphate as buffer and methanol in the ratio of 70:30) eluted in isocratic mode. The HPLC flow rate was 1.0 mL min -1 , and peaks were monitored at 230 nm using a photodiode array (PDA) detector. The column temperature was kept constant at 30°C, and the injection volume was 10 μL. The run time of the method was 16 min. The method was validated as per the International Conference on Harmonization (ICH) guidelines. Linearity was recorded at various concentrations ranging from 0.25 to 1.5 μg mL -1 for all the moxifloxacin impurities. Linearity, regression value, recovery, %relative standard deviation (RSD) of method precision values were found within the acceptance limits. The method for related substances (RS) in moxifloxacin was found to be specific, linear, accurate, precise, rugged, and robust. The validated method was suitable for the quantification of the RSs in moxifloxacin drug products. The method was applied in quality control lab for the analysis of moxifloxacin impurities in stability analysis., (© 2021 John Wiley & Sons, Ltd.)

A rapid stability-indicating reversed phase-ultrapure liquid chromatography (RP-UPLC) was developed and validated for the estimation of metformin (MET), linagliptin (LIN), and empagliflozin (EMP) combination in bulk and tablet dosage form using Kromasil C 18 column (2.1 × 50 mm, 1.8 μm) as a stationary phase and a mixture solution of 40% phosphate buffer (pH = 3) and 60% acetonitrile as mobile phase at a flow rate of 0.6 mL/min. The detection was performed at 248 nm using a photodiode array detector. The linearity, sensitivity, selectivity, robustness, specificity, precision, and accuracy were determined. The peak area response-concentration curve was rectilinear over the range of 50-150 (MET), 5-15 (LIN), and 10-30 μg/mL (EMP) with quantitation limits of 0.042 (MET), 0.023 (LIN), and 0.059 μg/mL (EMP). The proposed method was successfully validated for the determination of MET, LIN, and EMP simultaneously in combined tablet dosage form. The performance of the proposed method was compared with reported RP-UPLC methods and found to be rapid and economical. The developed and validated stability-indicating RP-UPLC method was appropriate for the quality control and drug analysis., (© 2020 John Wiley & Sons, Ltd.)

This paper presents a 10-step synthetic route for the preparation of a series of new back-to-back coupled 2,6-bis(pyrazol-1-yl)pyridine (bpp) ligands (L0-L3) decorated with tetraoctyl chains. Ligand L1 self-assembles with Zn(2+) ion to form a highly soluble metallo-supramolecular polymer 1 with M(n) ∼ 9600 g/mol. To demonstrate the processability of polymer 1, by following a "top-down" approach periodic one-dimensional fluorescent microstripes were fabricated on a silica substrate.