Thiamine hydrochloride(VB1):An efficient catalyst for one-pot synthesis of α-aminophosphonates under ultrasonic irradiation

An efficient synthesis of novelα-aminophosphonates by the reaction of aldehydes and amines with triethyl phosphite in the presence of the easily available,inexpensive,and nontoxic catalyst thiamine hydrochloride(VB1).This method affords theα-aminopho-sphonates under the influence of ultrasound irradiation in aqueous medium,in short reaction times(4-6 min),high yields(85-95%), with improved purity.The process is green,mild,inexpensive and excellent yields are the main compensation of this procedure.     

用于吖内酯合成的二氧化钛纳米晶体材料(英文)

Titanium dioxide nanoparticles were prepared by a electrochemical reduction method using para-meters such as current density, solvent polarity, distance between electrodes, and concentration of stabilizers to control the size of the nanoparticles. The nanoparticles were characterized by UV-Vis spectroscopy, X-ray diffraction, scanning electron microscopy and transmission electron microsco-py, and their catalytic performance was tested for the synthesis of a series of 4-aryldiene-2-phenyl-5(4)-oxazolones from the cyclodehydration and condensation of the respec-tive aldehyde, hippuric acid and acetic anhydride. Easy availability, reusability and eco-friendliness were some prominent features of the nanocrystalline titanium dioxide catalyst.     

Dendritic Polyglycerol‐Derived Nano‐Architectures as Delivery Platforms of Gemcitabine for Pancreatic Cancer

Dendritic polyglycerol‐co‐polycaprolactone (PG‐co‐PCL)‐derived block copolymers are synthesized and explored as nanoscale drug delivery platforms for a chemotherapeutic agent, gemcitabine (GEM), which is the cornerstone of therapy for pancreatic ductal adenocarcinoma (PDAC). Current treatment strategies with GEM result in suboptimal therapeutic outcome owing to microenvironmental resistance and rapid metabolic degradation of GEM. To address these challenges, physicochemical and cell‐biological properties of both covalently conjugated and non‐covalently stabilized variants of GEM‐containing PG‐co‐PCL architectures have been evaluated. Self‐assembly behavior, drug loading and release capacity, cytotoxicity, and cellular uptake properties of these constructs in monolayer and in spheroid cultures of PDAC cells are investigated. To realize the covalently conjugated carrier systems, GEM, in conjunction with a tertiary amine, is attached to the polycarbonate block grafted from the PG‐co‐PCL core. It is observed that pH‐dependent ionization properties of these amine side‐chains direct the formation of self‐assembly of block copolymers in the form of nanoparticles. For non‐covalent encapsulation, a facile “solvent‐shifting” technique is adopted. Fabrication techniques are found to control colloidal and cellular properties of GEM‐loaded nanoconstructs. The feasibility and potential of these newly developed architectures for designing carrier systems for GEM to achieve augmented prognosis for pancreatic cancer are reported.     

A high‐throughput LC–MS/MS method for determination of flunarizine in human plasma: Pharmacokinetic study with different doses

A high‐throughput and sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS) method has been developed and validated for the determination of flunarizine in human plasma. Liquid–liquid extraction under acidic conditions was used to extract flunarizine and flunarizine‐d8 from 100 μL human plasma. The mean extraction recovery obtained for flunarizine was 98.85% without compromising the sensitivity of the method. The chromatographic separation was performed on Hypersil Gold C₁₈ (50 × 2.1 mm, 3 μm) column using methanol–10 mm ammonium formate, pH 3.0 (90:10, v/v) as the mobile phase. A tandem mass spectrometer (API‐5500) equipped with an electrospray ionization source in the positive ion mode was used for detection of flunarizine. Multiple reaction monitoring was selected for quantitation using the transitions, m/z 405.2 → 203.2 for flunarizine and m/z 413.1 → 203.2 for flunarizine‐d8. The validated concentration range was established from 0.10 to 100 ng/mL. The accuracy (96.1–103.1%), intra‐batch and inter‐batch precision (CV ≤ 5.2%) were satisfactory and the drug was stable in human plasma under all tested conditions. The method was used to evaluate the pharmacokinetics of 5 and 10 mg flunarizine tablet formulation in 24 healthy subjects. The pharmacokinetic parameters C_max and AUC were dose‐proportional.     

Modified soybean oil as a reactive diluent: Synthesis and characterization

Soybean oil was modified in two steps: (1) conjugation of soybean oil and (2) Diels‐Alder addition with 3‐(trimethoxysilyl)propyl methacrylate, 2,2,2‐trifluoroethyl methacrylate and triallyl ether acrylate. The structures were characterized using ¹H NMR, ¹³C NMR, ¹³C‐¹H gradient heteronuclear single quantum coherence (gHSQC) NMR spectroscopy, and MALDI‐TOF mass spectrometry. The ¹³C‐¹H gHSQC NMR spectra helped confirm the formation of a cyclohexene ring in all reactions, indicating a Diels‐Alder addition. The diluent efficiency of modified soybean oil was evaluated in long oil alkyd formulation. Triallyl ether functionalized soybean oil resulted in the highest reduction in the viscosity of the alkyd formulations. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3045–3059     

Evaluation of antioxidant activity and DNA cleavage protection effect of naphthyl hydroxamic acid derivatives through conventional and fluorescence microscopic methods

Antioxidant capacity of N-(1-naphthyl)valerohydroxamic acid (NVHA) and N-(1-naphthyl)phenylacetohydroxamic acid (NPAHA) has been evaluated by a novel approach employing the fluorescence microscopic single molecule observation method. This method allows direct observation of the changes in single DNA molecules. The DNA cleavage protection activity of the compounds was also assessed by the gel electrophoresis method. The applied methods confirmed that both compounds are capable of inhibiting the free radical mediated DNA damage. Free radical scavenging activity was assessed via the 2,2′-diphenyl-1-picrylhydrazyl free radical (DPPH) and lipid peroxidation inhibition methods. The effective concentration causing a 50 % inhibition of the DPPH concentration, EC50, was found to be 371.54 mM for NVHA and 365.95 mM for NPAHA. Its lipid peroxidation inhibition ability was calculated to be 40.91 % at 371.54 mM for NVHA and 41.14 % at 365.95 mM for NPAHA. These results show the antioxidant potential of the naphthyl hydroxamic acids.     

Ultrasound-promoted greener approach to synthesize α-hydroxy phosphonates catalyzed by potassium dihydrogen phosphate under solvent-free condition

We report a new environmentally-benign, convenient, and facile methodology for the synthesis of α-hydroxyphosphonates from an aromatic/heteroaromatic aldehyde with triethyl phosphite in the presence of potassium dihydrogen phosphate (KH₂PO₄) under ultrasound-assisted solvent-free conditions. Furthermore, a series of compounds were synthesized and characterized by melting point, EI-MS, NMR, and IR tools. Utilization of easy reaction conditions, isolation, and purification makes this manipulation very interesting from an economic perspective.     

Prospecting Exopolysaccharides Produced by Selected Bacteria Associated with Marine Organisms for Biotechnological Applications

In this study, bacteria associated with marine organisms were screened for the production of exopolysaccharides(EPSs) on MY media containing sea salts(2.5%-10%). Three selected isolates were identified as Alteromonas sp. PRIM-21, Nitratireductor sp. PRIM-24 and Enterobacter sp. PRIM-26 using 16 S r RNA gene sequencing. Optimization of the growth and EPS production kinetics in relation to incubation time were assessed. The purified EPS yield was 590, 650 and 540 mg·L-1 culture media respectively in Alteromonas sp. PRIM-21, Nitratireductor sp. PRIM-24 and Enterobacter sp. PRIM-26. Biochemical and FTIR analyses revealed the presence of biologically important functional groups in the EPS produced by all the three isolates. The EPS produced by Nitratireductor sp. PRIM-24 and Alteromonas sp. PRIM-21 showed 2.0% sulfate content. These bacterial EPS also showed antioxidant and emulsifying activities and the EPS produced by Enterobacter sp.PRIM-26 showed significantly higher antioxidant activities in terms of superoxide(IC50 0.33 mg·mL -1) and DPPH(IC50 0.44 mg·mL -1) radical scavenging. It also showed higher emulsifying activities against selected hydrophobic substrates with EI24 values above 60%. From the results of the study, it can be concluded that the isolated bacteria produce EPS that can be investigated in detail for biotechnological applications.     

A general design for one dimensional discrete sine transform

Implementation of discrete sine transform (DST) is proposed, by folding the input data. This results in recursive structure, besides saving in the overall computation cycles. A simplified architecture to derive DST kernel has also been suggested.