Donepezilium oxalate trihydrate,a therapeutic agent for Alzheimer's disease

Donepezil, a cholinesterase inhibitor with good central nervous system penetration, has been crystallized as a tertiary amine salt with a disordered oxalate anion to give the title compound, (R,S)‐1‐benzyl‐4‐[(5,6‐dimethoxy‐1‐oxoindan‐2‐yl)methyl]piperidinium hydrogen oxalate trihydrate, C₂₄H₃₀NO₃⁺·C₂HO₄⁻·3H₂O. The indanone and piperidine ring planes are inclined at an angle of 33.4 (1)°. A comparison is made with the piperidinium cation bound in acetyl­cholinesterase in the solid state. The methyl­ene units bridging the indanone–piperidine–benzyl groups determine the mol­ecular shape and conformational features. The structure is stabilized mainly by O—H⋯O and N—H⋯O hydrogen bonds, with water mol­ecules mediating inter­actions between oxalate anions and donepezilium cations.     

Potential of Kalopanax septemlobus Leaf Extract in Synthesis of Silver Nanoparticles for Selective Inhibition of Specific Bacterial Strain in Mixed Culture

Silver nanoparticles (AgNPs) were synthesised using Kalopanax septemlobus plant leaf extracts. UV-visible spectrophotometric, Fourier-transform infrared, electron dispersive X-ray spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses confirmed synthesis of AgNPs. TEM micrographs revealed presence of well-dispersed AgNPs predominantly of small size and different shapes with an average particle size of 30.8 nm. Antimicrobial susceptibility tests of AgNP treatments revealed variability in sensitivity of bacteria Bacillus cereus and Saccharophagus degradans under study. Minimum inhibitory concentration (MIC) values of the AgNPs for B. cereus and S. degradans were found to be 30 and 10 μg/mL, respectively. The mixed culture of B. cereus and S. degradans treated with AgNPs at 10 μg/mL showed increase in growth with time, suggesting survival of bacteria in liquid media. The plating of mixed culture before AgNP treatment showed presence of both bacteria, but 24-h-old mixed culture treated with AgNPs at the concentration of 10 μg/mL showed presence of B. cereus colonies. SEM micrographs revealed damage to S. degradans cells but no effect on B. cereus cells after AgNP treatment. Confocal microscopic observations of AgNP-treated mixed cultures by Nile blue A staining indicated intact polyhydroxyalkanoates producing flourescent cells of B. cereus but damage and deformities in S. degradans cells. This study suggests that AgNPs can selectively inhibit growth of S. degradans and retain B. cereus at MIC of S. degradans. This report is a case study for selective inhibition of one bacteria and growth of the other in a culture using plant-synthesized silver nanoparticles.     

Development of ion chromatography and capillary electrophoresis methods for the determination of Li in Li–Al alloy

Two methods were developed for determination Li content in Li–Al alloy by employing ion chromatography (IC) and capillary electrophoresis (CE) without any prior separation of Al matrix. In absence of suitable certified reference material the two methods were used to validate each other. Using a high capacity column and a weaker eluent methane sulphonic acid, it was possible to separate Li in IC without eluting strongly retained Al. The method showed good precision and sensitivity and was extended for analysis of routine samples. In the case of CE using imidazole as co-ion, Li was detected in CE by indirect detection. In view of no interference from Al, samples were analyzed without any matrix separation. The CE method was used successfully for sample analysis and results were compared with IC results.     

Ligand-free C–N bond formation in aqueous medium using a reusable Cu–Mn bimetallic catalyst

A general ligand-free protocol has been described for the recyclable and reusable Cu–Mn catalyzed C–N bond forming cross coupling reaction of arylboronic acids with various amines to form N-arylated amine products in aqueous medium affording excellent yields under ambient conditions, in 3–4 h.     

Bulk magnetic properties of tetravalent ion substituted Cu-ferrite

The lattice parameter,a, increases with the increase of Ti⁴⁺ substitution while it decreases with the increase of Ge⁴⁺ substitution in Cu_1+x A _x Fe_2–2x O₄ compounds [A=Ti⁴⁺, Ge⁴⁺Sn⁴⁺]. On substitution of Sn⁴⁺,a does not vary. CuFe₂O₄ exhibits single domain (SD) behaviour that changes to multi domain (MD) type on Ti⁴⁺ substitution. On Ge⁴⁺ substitution initially all the compositions exhibit SD behaviour while forx>0.2 they show MD behaviour. All Sn⁴⁺ substituted compositions exhibit SD behaviour. The Curie temperature decreases on addition of Ti⁴⁺, Sn⁴⁺ and Ge⁴⁺. The magnetic momentn _B (77 K) initially increases and then decreases with the substitution of Ti⁴⁺, Ge⁴⁺, and Sn⁴⁺. This is explained by cation distribution and reduction of Fe³⁺ ions.The authors wish to thank Prof. R. N. Patil for encouragment and useful discussion. One of the authors (B.L.P.) is grateful to UGC (New Delhi) for granting Teacher Fellowship for Ph.D. course.     

Studies on grain boundary effects in spray deposited BICOVOX 0.1 films on platinum-coated stainless steel substrate

Thin film of Bi₂Co_0.1V_0.9O_5.35 is deposited by using spray pyrolysis technique on platinum-coated stainless steel substrate. Impedance measurements done in the frequency range 1 to 10 MHz and in the temperature range 502 to 720 K revealed two relaxation processes with distinguishable time constants. The first corresponds to the grain interior charge transfer while the second could be due to grain boundary. The change in polarization seems to be associated with hopping of charge carriers showing Arrhenius behavior with increase in temperature. The relaxation frequency of grain interior transport for the thin film ranges from 96 kHz to 2.59 MHz. The blocking factor was found to be increasing with increase in temperature at low temperature region from 502 to 640 K. At higher temperature above 640 K, diffusive nature of grain boundaries is inferred with the decrease in blocking factor. The same inference is derived by specific grain boundary conductivity calculations since specific grain boundary conductivity decreases in low temperature region while it increases rapidly at higher temperature. These observations prove the grain boundaries to be blocking in lower temperatures while at higher temperatures above 640 K they turn diffusive. These changes are attributed to structural phase transition, or ordering of vacancies in Bi₂Co_0.1V_0.9O_5.35 films.     

Tetramisole-Chromium Trioxide Complex: A New Oxidant of Organic Compounds @

Tetramisole has been found to complex with chromium trioxide. Elemental analysis suggests a 1:1 complex formation and IR data suggest the ligand binding through N-7 nitrogen. The new complex is capable of selectively oxidizing alcohols, including benzyl and allylic alcohol, to carbonyl compounds under mild conditions.