Plasma analysis of celiprolol by HPTLC: a useful technique for pharmacokinetic studies

A rapid and sensitive high performance, thin-layer chromatographic (HPTLC) method has been developed for the measurement of celiprolol in human plasma and its use in pharmacokinetic studies has been evaluated. Detection and quantitation were performed without using an internal standard. A simple extraction procedure was followed for extracting celiprolol from plasma and a known amount of the extract was spotted on precoated silica gel 60 F254 plates using a Camag Linomat IV autosampler. Celiprolol was quantitated using a Camag TLC Scanner 3. The average recovery of authentic analytes (20 to 200 ng/mL) added to plasma was 72.06 +/- 2.8% and the lowest amount of celiprolol that could be detected was 10 ng/mL. The method provides a direct estimate of the amount of celiprolol present in plasma. Pharmacokinetic parameters of 2 marketed preparations have also been determined after oral administration to 12 healthy human volunteers.     

Nonlinear low-frequency electrostatic wave dynamics in a two-dimensional quantum plasma

The problem of two-dimensional arbitrary amplitude low-frequency electrostatic oscillation in a quasi-neutral quantum plasma is solved exactly by elementary means. In such quantum plasmas we have treated electrons quantum mechanically and ions classically. The exact analytical solution of the nonlinear system exhibits the formation of dark and black solitons. Numerical simulation also predicts the possible periodic solution of the nonlinear system. Nonlinear analysis reveals that the system does have a bifurcation at a critical Mach number that depends on the angle of propagation of the wave. The small-amplitude limit leads to the formation of weakly nonlinear Kadomstev–Petviashvili solitons.     

Grinding and Microwave‐assisted Synthesis of Heterocyclic Molecules in High Yields and Their Biological Evaluation

Cis‐cyclohexane1,2‐dicarboxylic acid ( 1a ), phthalic acid ( 1b ), and pyrazine 2,3‐ dicarboxylic acid ( 1c ) on grinding with hydrazine hydrate ( 2a ) gave 2‐aminohexahydro‐1H‐isoindole‐1,3(2H)‐dione ( 3a ), 2‐amino‐1H‐isoindole‐1,3(2H)‐dione ( 3b ), and 6‐amino‐5H‐pyrrolo[3,4‐b]pyrazine‐5,7(6H)‐dione ( 3c ), respectively. Condensation of ( 3a , 3b , 3c ) with aldehydes ( 4x , 4y , 4z ) and 2‐cyanopyridine, 4‐cyanopyridine, 2‐cyanopyrazine ( 5x , 5y , 5z ) under microwave irradiation gave corresponding azomethine ( 6ax , 6ay , 6az , 6bx , 6by , 6bz , 6cx , 6cy , 6cz ) and amidine ( 7ax , 7ay , 7az , 7bx , 7by , 7bz , 7cx , 7cy , 7cz ) derivatives, respectively. Fully characterized azomethine ( 6ax , 6ay , 6az , 6bx , 6by , 6bz , 6cx , 6cy , 6cz ) and amidine ( 7ax , 7ay , 7az , 7bx , 7by , 7bz , 7cx , 7cy , 7cz ) derivatives were screened for anti‐inflammatory and anticancer activity against five human cancer cell lines. Compound 7cx exhibited 35% anti‐inflammatory activity at a dose of 50 mg/kg p.o. whereas standard drug ibuprofen showed 39% activity at a dose of 50 mg/kg p.o. Compounds 6bz , 7cx , 7cz (breast T47D), 6bz , 6cy (lung NCI H‐522), 6bx , 7bz (colon HCT‐15), 6bz (ovary PA‐1) and 6bx , and 6cz (liver HepG‐2) exhibited good (35–41% inhibition at 10 μM c) anticancer activity. IC₅₀ values of 6bx , 6bz , 6cy , 6cz , 7bz , 7cx , and 7cz against various cancer cell lines and normal cell (COS‐1) are also reported.     

An expedient stereoselective synthesis of (Z)- and (E)-allyl iodides from Baylis-Hillman adducts along with selective iodination of benzylic alcohols using the polymethylhydrosiloxane-iodine system

A stereoselective method has been developed for the synthesis of (Z)- and (E)-allyl iodides from Baylis-Hillman adducts using polymethylhydrosiloxane (PMHS) and iodine in chloroform at room temperature. In addition, the reagent system has been utilized for the iodination of benzylic alcohols selectively.     

A highly efficient stereoselective synthesis of (Z)- and (E)-allyl iodides from Baylis-Hillman adducts

A highly efficient synthesis of (Z)- and (E)-allyl iodides has been accomplished by treatment of Baylis-Hillman adducts with iodine and triphenylphosphine in methylene chloride at room temperature. The method is associated with mild reaction conditions, high yields and excellent stereoselectivity.     

One-step hydrothermal synthesis of marigold flower-like nanostructured MoS<Subscript>2</Subscript> as a counter electrode for dye-sensitized solar cells

MoS₂ thin films with marigold flower-like nanostructures were grown on conductive fluorine-doped tin oxide (FTO) substrates through a one-step hydrothermal synthesis for their application as counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). Different MoS₂ thin film samples (A–D) were grown on FTO slides using different concentrations of precursors (sodium molybdate and thioacetamide), while keeping the Mo/S molar ratio constant (1:4.6), in all samples. The effect of varying precursor concentrations (3.2–12.6 mM on MoS₂ basis) on the structure of the nanostructured thin films and their performance as DSSC-CEs was investigated. Scanning electron microscopy revealed a material with an infolded petal-like morphology. With increasing precursor concentration, the petal-like structures tended to form bunched nanostructures (100–300 nm) resembling marigold flowers. X-ray diffraction analysis, X-ray photoelectron, and Raman spectroscopy studies showed that the thin films were composed of hexagonal MoS₂ with good crystallinity. Hall effect measurements revealed MoS₂ to be a p-type semiconductor with a carrier mobility of 219.80 cm² V^?1 s^?1 at room temperature. The electrochemical properties of the thin films were examined using cyclic voltammetry and electrochemical impedance spectroscopy. The marigold flower-like MoS₂ thin films showed excellent electrocatalytic activity towards the I¯/I₃¯ reaction and low charge transfer resistance (R_ct) values of 14.77 Ω cm^?1, which was close to that of Pt electrode (12.30 Ω cm^?1). The maximum power conversion efficiency obtained with MoS₂ CE-based DSSCs was 6.32%, which was comparable to a Pt CE-based DSSC (6.38%) under one sun illumination. Similarly, the maximum incident photon-to-charge carrier efficiency exhibited by MoS₂ CE-based DSSCs was 65.84%, which was also comparable to a Pt CE-based DSSC (68.38%). The study demonstrated that the marigold flower-like nanostructured MoS₂ films are a promising alternative to the conventional Pt-based CEs in DSSCs.

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Carbon Nanosheets by Morphology‐Retained Carbonization of Two‐Dimensional Assembled Anisotropic Carbon Nanorings

Two‐dimensional (2D) carbon nanomaterials possessing promising physical and chemical properties find applications in high‐performance energy storage devices and catalysts. However, large‐scale fabrication of 2D carbon nanostructures is based on a few specific carbon templates or precursors and poses a formidable challenge. Now a new bottom‐up method for carbon nanosheet fabrication using a newly designed anisotropic carbon nanoring molecule, CPPhen, is presented. CPPhen was self‐assembled at a dynamic air–water interface with a vortex motion to afford molecular nanosheets, which were then carbonized under inert gas flow. Their nanosheet morphologies were retained after carbonization, which has never been seen for low‐molecular weight compounds. Furthermore, adding pyridine as a nitrogen dopant in the self‐assembly step successfully afforded nitrogen‐doped carbon nanosheets containing mainly pyridinic nitrogen species.     

Chemoselective deprotection of trityl ethers using silica-supported sodium hydrogen sulfate

A highly selective method for the cleavage of trityl ethers over a wide range of functional groups has been developed using silica-supported sodium hydrogen sulfate (NaHSO₄-SiO₂) as a heterogeneous catalyst. The conversion occurred at room temperature and the yields of the alcohols were found to be excellent.     

Copper-mediated controlled radical ring-opening polymerization (RROP) of a vinylcycloalkane

This investigation reports controlled ring-opening polymerization of a vinylcyclopropane via copper-mediated atom transfer radical polymerization which leads to predominantly 1,5 ring-opening polymerization.