Microwave-assisted expeditious hydrolysis of isobenzofuranone derivatives using silica supported acid under organic solvent-free conditions

Silica sulfuric acid was found to be an efficient, reusable and environment-friendly catalyst for fast hydrolysis of various isobenzofuranone to corresponding 2-ketomethylquinoline derivatives in a high yield under solvent-free using microwave irradiation. As the activator of silica sulfuric acid the wet SiO₂ was chosen. The reactions in conventional conditions were compared with the microwave assisted reactions. This approach can prove beneficial since the recovery of solvents from conventional reaction systems always results in some losses.     

Development a robust ionic liquid-based dispersive liquid-liquid microextraction against high concentration of salt combined with flame atomic absorption spectrometry using microsample introduction system for preconcentration and determination of cobalt in water and saline samples

A robust ionic liquid-based method for dispersive liquid-liquid microextraction was developed for the determination of cobalt in saline samples. Its robustness was increased by introducing a common ion of the IL into the sample solution. The concentration of cobalt in the settled phase of the ionic liquid was determined by the FAAS using a homemade microsample injection valve. Under the optimized conditions, the calibration graph was linear in the concentration range from 0.4 to 120 ??g L^?1 with the detection limit of 0.1 ??g L^?1. Accuracy was checked against the ISO standard method. The method was successfully applied to the determination of cobalt in water and saline samples.     

Nanocomposite hydrogel from grafting of acrylamide onto HPMC using sodium montmorillonite nanoclay and removal of crystal violet dye

Hydrogel nanocomposites were synthesized from grafting of acrylamide onto hydroxypropyl methylcellulose using methylenebisacrylamide crosslinker and sodium montmorillonite (Na-MMt) nanoclay. The effect of nanoclay content on the swelling of nanocomposites was investigated and an optimum swelling capacity was obtained at 12.7 wt% of Na-MMt. The effect of salt solutions on the swelling of nanocomposites revealed that the degree of swelling of samples depends only slightly on the salinity. The structure of nanocomposites was characterized by XRD, SEM, FTIR, and TEM techniques. The XRD and TEM results confirmed the exfoliation of Na-MMt nanoclay in nanocomposite matrix. The morphology of the nanocomposites was characterized by SEM technique and according to the results a loose surface was observed. The nanocomposite hydrogels were evaluated to remove cationic crystal violet dye from water. The investigation of the dye adsorption capacity and rate of nanocomposite hydrogels as a function of Na-MMt content revealed that the both adsorption capacity and rate is enhanced as the nanoclay content is increased in nanocomposite composition. The experimental equilibrated adsorption capacity of nanocomposites was analyzed using Freundlich and Langmuir isotherm models. The best fit to the experimental data was obtained with the Langmuir model.     

A three‐component process for the synthesis of 2,3‐dihydroquinazolin‐4(1H)‐one derivatives using nanosized nickel aluminate spinel crystals as highly efficient catalysts

NiAl₂O₄ spinel nanocrystals were synthesized as mesoporous catalysts and were fully characterized using Fourier‐transform infrared spectroscopy (FT‐IR), X‐ray diffraction patterns (XRD), scanning electron microscopy (SEM), and Energy‐dispersive X‐ray spectroscopy (EDS). These nanocrystals catalyzed the synthesis of 2,3‐dihydroquinazolin‐4(1H)‐one derivatives via a one‐pot, three‐component condensation reaction of aromatic aldehydes, isatoic anhydride, and ammonium acetate or primary aromatic amine under microwave irradiation. By far, the most obvious advantages of the offered process are efficiency and recyclability of the catalyst as well as a significantly shorter reaction time.     

H3PMo12O40‐immobilized chitosan/Co3O4: A novel and recyclable nanocomposite for the synthesis of pyrimidinedione derivatives

An efficient three‐component reaction of aromatic aldehydes, 6‐aminouracil/6‐amino‐1,3‐dimethyluracil and 4‐hydroxycoumarin in the presence of a novel heterogeneous catalyst H₃PMo₁₂O₄₀‐immobilized Co₃O₄/chitosan led to a synthesis of a new class of pyrimidinedione derivatives under reflux conditions. The magnetically recoverable nanocomposite of Co₃O₄/chitosan/H₃PMo₁₂O₄₀ was fully characterized by Fourier transform‐infrared spectrophotometry, scanning electron microscopy, X‐ray powder diffraction, energy‐dispersive X‐ray spectroscopy, vibrating‐sample magnetometry and N₂ adsorption–desorption by Brunauer–Emmett–Teller analysis. Results show that Keggin‐type 12‐molybdophosphoric acid immobilized into the network of the cross‐linked chitosan with super‐paramagnetic Co₃O₄ nanoparticles. The present method offers several advantages, such as simple procedure, short reaction times and excellent yields of products. The novelty of the catalyst, high catalytic activity, easy separation from the reaction with an external magnetic field and reusability of the catalyst in six consecutive runs are additional eco‐friendly attributes of this catalytic system.     

Silica‐tethered cuprous acetophenone thiosemicarbazone (STCATSC) as a novel hybrid nano‐catalyst for highly efficient synthesis of new 1,2,3‐triazolyl‐based metronidazole hybrid analogues having potent antigiardial activity

The preparation, characterization and application of silica‐tethered cuprous acetophenone thiosemicarbazone (STCATSC) as a novel hybrid nano catalyst for synthesis of new 1,2,3‐triazolyl‐based metronidazole hybrid analogues is described. STCATSC is fully characterized by different microscopic, spectroscopic and physical techniques, including scanning electron microscopy (SEM), transmission, X‐ray diffraction (XRD), Energy‐dispersive X‐ray spectroscopy (EDS), thermogravimetric analysis (TGA), FT‐IR and inductively coupled plasma (ICP) analysis. This catalyst is used to prepare the new 1,2,3‐triazolyl‐based metronidazole hybrid analogues. The ‘Click’ Huisgen cycloaddition reaction of 2‐methyl‐5‐nitro‐1‐prop‐2‐ynyl‐1H‐imidazole with diverse β‐azidoalcohols in a THF‐water media at R.T. provides the products in good to excellent yields using STCATSC. STCATSC is proved to be a stable, low cost, reusable and environmentally benign hybrid catalyst. Products are in vitro tested against Giardia lamblia (G. lamblia) in which determined that all compounds exhibit varied promising antigiardial activity compare to metronidazole as a reference drug. Among the products, 1‐(4‐((2‐methyl‐5‐nitro‐1H‐imidazol‐1‐yl)methyl)‐1H‐1,2,3‐triazol‐1‐yl)‐3‐phenethoxypropan‐2‐ol and 1‐(4‐((2‐methyl‐5‐nitro‐1H‐imidazol‐1‐yl)methyl)‐1H‐1,2,3‐triazol‐1‐yl)‐3‐(3‐phenylpropoxy)propan‐2‐ol are demonstrated to exhibit the potent antigiardial activity even stronger than metronidazole.     

Synthesis and Multinuclear NMR Study of Benzoyl Methylene Triparatolylphosphorane Ylide and the Reaction of this Ylide with Mercury(II) Halides

The reaction of the title ylide {PhCOCHP(p-tolyl)₃} with Pd(II), Pt(II). Hg(II), and Ag(I) in equimolar ratios using CH₃CN, CH₃OH, and CH₂Cl₂ as solvents have yielded [{(p-tolyl)₃PCHCOC₆H₅} PdCl₂]₂ (I), [{(p-tolyl)₃ PCHCOC₆H₅} PtCl₂]₂(2), [Hg(NO₃)₂ {(p-tolyl)₃ PCHCOC₆H₅}](3), and [Ag{(p-tolyl)₃ PCHCOC₆H₅ < eqid1 > ₂]⁺ (4). The IR, ¹H ¹³C, and ³¹P NMR together with micro analysis data of the products were obtained.     

Comparative study of Box–Behnken,central composite,and Doehlert matrix for multivariate optimization of Pb (II) adsorption onto Robinia tree leaves

A comparative study of Box–Behnken, central composite, and Doehlert matrix was performed on the adsorption of Pb (II) by Robinia tree leaves in a batch system. As a case study, uptake capacity (q) and removal efficiency (R) of Pb (II) biosorption have been evaluated with all theses approaches. The advantages and limitations of these different response surface techniques have been experimentally considered. The results show the different statistical predictability of Doehlert matrix and Box–Behnken design at 95% confidence level comparable with some extent with that of central composite design at some extreme conditions. An environmental and economical comparison was also carried out between individual and simultaneous optimization of removal efficiency (R) and uptake capacity (q) using desirability function. Optimization of q proves only to have advantages over R or simultaneous optimization of R and q in this particular biosorption process. Copyright © 2013 John Wiley & Sons, Ltd.     

Optimized preparation and preliminary evaluation of [64Cu]–DOTA–trastuzumab for targeting ErbB2/Neu expression

Breast cancer radioimmunoscintigraphy targeting HER2/neu expression is a growing field of work in nuclear medicine research. Trastuzumab is a monoclonal antibody that binds with high affinity to HER2/neu, which is over expressed on breast and other tumors. Developing new tracers for the detection of this cancer is of great interest. In this study, trastuzumab was successively labeled with [⁶⁴Cu]CuCl₂ after conjugation with DOTA-NHS-ester. The conjugate was purified by molecular filtration, the average number of DOTA conjugated per mAb was calculated and total concentration was determined by spectrophotometric method. DOTA–trastuzumab was labeled with ⁶⁴Cu produced by ⁶⁸Zn(p,αn)⁶⁴Cu nuclear reaction (30 MeV protons at 180 μA). Radiochemical purity, integrity of protein after radiolabeling and immunoreactivity of radiolabeled mAb trastuzumab with HER2/neu antigen and SkBr3 cell line were performed by RIA. In vitro stability of radiolabeled mAb in human serum was determined by thin layer chromatography. In vitro internalization studies were performed with the SkBr3 cell line and the tissue biodistribution of the ⁶⁴Cu–DOTA–trastuzumab was evaluated in wild-type rat (90 ± 5.5 μCi, 2, 6, 12, 24 h p.i.). The radioimmunoconjugate was prepared with a radiochemical purity of higher than 96 ± 0.5 % (ITLC) and specific activity as high as 5.3 μCi/μg. The average number of chelators per antibody for the conjugate used in this study was 5.8/1. The sample was showed to have similar patterns of migration in the gel electrophoresis. The ⁶⁴Cu–DOTA–trastuzumab showed high immunoreactivity towards HER2/neu antigen and SkBr3 cell line. In vitro stability of the labeled product was found to be more than 94 % in PBS and 82 ± 0.5 % in human serum over 48 h. In vitro internalization studies of the ⁶⁴Cu–DOTA–trastuzumab showed that up to 11.5 % of the radioimmunoconjugate internalized after 10 h. The accumulation of the radiolabeled mAb in liver, skin, intestine, lung, spleen, kidney and other tissues demonstrates a similar pattern to the other radiolabeled anti-HER2 immunoconjugates. ⁶⁴Cu–DOTA–trastuzumab is a potential compound for molecular imaging of PET for diagnosis and treatment studies and follow-up of HER2 expression in oncology.