Transition metal catalyzed carboannulation of diazabicyclic alkenes with ambiphilic bifunctional reagents: a facile route towards functionalized indanones and indanols

Functionalized indanones are readily prepared in good to excellent yields by the Pd/Rh catalyzed carboannulation of bicyclic and tricyclic hydrazines with 2-iodobenzonitrile, 2-cyanophenylboronic acid and 2-formylphenylboronic acid. The reaction with 2-formylphenylboronic acid afforded 3,4-disubstituted cyclopentenes as minor product along with indanones under Rh catalyzed conditions, whereas indanols were obtained as the major product under Pd catalyzed conditions. The products obtained can be synthetically manipulated easily to pharmaceutically important molecules.     

Molecular Characterization of N-Terminal Pro-sequence of Keratinase Ker P from Pseudomonas aeruginosa: Identification of Region with Chaperone Activity

In silico analysis of keratinase Ker P from Pseudomonas aeruginosa revealed that its full gene of 1,497 bp constituted of a 72-bp signal sequence along with a long 520 bp pro-sequence and 905 bp core region. Position specific multiple sequence alignment of Ker P protein with other distant proteases revealed high variability within their N-terminal regions while the core protein was considerably conserved. Ker P (F1) and its four N-terminal truncations (F2-F5) lacking 72, 177, 405, 507 bp, respectively, were cloned and constitutively expressed as extracellular protein in pEZZ-18 secretory vector with Escherichia coli HB101 as the expression host. Ker P F1, Ker P F2, Ker P F3 and Ker P F4 products were active whereas no keratinolytic activity was obtained in Ker P F5. Further analysis revealed that only 187 bp pro-sequence region is required for correct folding of the protein into its active conformation and, thus, has chaperone-like activity. Further, comparative biochemical characterization revealed that the full-length keratinase Ker P F1 was catalytically more efficient than the truncated forms. Among the truncated enzymes, keratinase Ker P F4 exhibited better thermostability than Ker P F2 with a t(1/2) of >1 h at 60 °C. It also had a higher V (max) and K (m) on casein as compared with Ker P F2. However, no significant variation was observed with respect to kinetics on synthetic substrates.     

Propagation of plane waves in microstretch fluid

The propagation of plane harmonic waves are studied in a microstretch fluid medium. It is found that five basic waves can propagate at distinct speeds in an infinite linear homogeneous isotropic microstretch fluid. Out of these five waves, one is a longitudinal micro-rotational wave, two are coupled longitudinal waves and remaining two are coupled transverse waves. The longitudinal micro-rotational wave travels independently and is not influenced by the microstretching of the medium, while the coupled longitudinal waves arise due to the presence of microstretching and coupled transverse waves arise due to the presence of micro-rotation in the medium. Speed of propagation of all the waves are found to be complex valued and dispersive at low frequency, but almost non-dispersive at high frequency. Due to complex valued speeds of propagation, all the waves are attenuating but differently. Coupled sets of longitudinal waves reduce to a longitudinal wave of micropolar fluid in the absence of microstretching. Reflection phenomena of a set of coupled longitudinal waves incident obliquely at the free surface of a microstretch fluid half-space has been investigated. Closed formulae for the reflection coefficients are presented and computed numerically for a particular medium. The real and imaginary parts of the complex speeds of all the waves and their corresponding attenuation coefficients have also been studied numerically and depicted graphically against frequency parameter.     

Quantification of Tricyclic and Nontricyclic Antidepressants in Spiked Plasma and Urine Samples Using Microextraction in Packed Syringe and Analysis by LC and GC-MS

In this paper, a highly selective Sudan IV molecularly imprinted polymer was synthesized by surface molecular imprinting technique in combination with a sol?Cgel process using ??-aminopropyl triethoxysilane as functional monomer, tetraethoxysilane as cross-linker and activated silica gel as support material. The imprinted polymer was characterized by FT-IR spectra, scanning electron micrograph and adsorption experiments and it was exhibited good recognition and selective ability, offered a faster rate for the adsorption of Sudan IV. Using the imprinted material as sorbent, a solid-phase extraction coupled with high-performance liquid chromatography method for determination of trace Sudan IV was presented. The detection limit (S/N = 3) was 25.2 ng L^?1, and the RSD for five replicate was 2.86%. With a loading flow rate of 2.5 mL min^?1 for loading 30 mL, an enrichment factor of 104 was achieved. This method was applied for extraction and determination of chilli powder and duck egg samples with good recoveries ranging from 85.3 to 98.1%.     

Synthesis,characterization, and evaluation of antimicrobial activities of a new class of macrocyclic phosphonates

A series of a new class of phosphorus analogue macrocycles was accomplished by condensation of N‐substituted‐[bis(3,5‐dimethyl‐2‐hydroxybenzyl)]‐amines with various phosphorus dichlorides in dry toluene in the presence of triethylamine at 0–50°C. All the title compounds were evaluated for antimicrobial activity to determine their efficacy and were effective in suppressing the growth of bacteria and fungi. The chemical structures of the title products were characterized by IR, ¹H, ¹³C, ³¹P‐NMR, mass spectral studies, and elemental analysis. J. Heterocyclic Chem., (2011).     

Experimental IR and Raman spectra and quantum chemical studies of molecular structures, conformers and vibrational characteristics of L-ascorbic acid and its anion and cation

IR and spectra of the L-ascorbic acid (L-AA) also known as vitamin C have been recorded in the region 4000-50 cm(-1). In order to make vibrational assignments of the observed IR and Raman bands computations were carried out by employing the RHF and DFT methods to calculate the molecular geometries and harmonic vibrational frequencies along with other related parameters for the neutral L-AA and its singly charged anionic (L-AA(-)) and cationic (L-AA(+)) species. Significant changes have been found for different characteristics of a number of vibrational modes. The four ν(O-H) modes of the L-AA molecule are found in the order ν(O(9)-H(10))>ν(O(19)-H(20))>ν(O(7)-H(8))>ν(O(14)-H(15)) which could be due to complexity of hydrogen bonding in the lactone ring and the side chain. The CO stretching wavenumber (ν(46)) decreases by 151 cm(-1) in going from the neutral to the anionic species whereas it increases by 151 cm(-1) in going from the anionic to the cationic species. The anionic radicals have less kinetic stabilities and high chemical reactivity as compared to the neutral molecule. It is found that the cationic radical of L-AA is kinetically least stable and chemically most reactive as compared to its neutral and anionic species.     

DFT and ab initio quantum chemical studies on p-cyanobenzoic acid

The Fourier transform infrared (FTIR) and FT-Raman spectra of p-cyanobenzoic acid (CBA) have been recorded in the range 4000-400 and 4000-100 cm(-1), respectively. The complete vibrational assignment and analysis of the fundamental modes of the compound were carried out using the observed FTIR and FT-Raman data. The vibrational frequencies determined experimentally were compared with theoretical wavenumbers obtained from ab initio HF and DFT-B3LYP gradient calculations employing 6-31G**, 6-311++G** and cc-pVTZ basis sets for the optimised geometry of the compound. The geometry and normal modes of vibration obtained from the HF and DFT methods are in good agreement with the experimental data. The normal coordinate analysis was also carried out with ab initio force fields utilising Wilson's FG matrix method. The interactions of cyano and carboxylic acid groups with the skeletal vibrational modes were investigated.     

Use of a crown ether-heteropoly acid precipitate as a potassium ion-selective membrane electrode

Summary A Potassium ion-selective electrode based on dibenzo-18-crown-6-tungstophosphoric acid precipitate membrane is prepared and conditions for the best functioning have been investigated. The working concentration and pH-range of the electrode is 2.0×10^–2 to 1.3×10^–6 mol/l and 2.9–6.5, respectively. The selectivity coefficient values for a large number of cations are quite low except for caesium and ammonium ions. The electrode can tolerate non-aqueous content upto 20%.

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Kaliumion-sensitive Membranelektrode auf Basis von Kronenether-Heteropolysäure

     

Efficient allylation of aldehydes with allyltributylstannane catalyzed by CuI

Cuprous iodide has been found to be a very effective catalyst for allylation of aldehydes with allyltributylstannane. The catalytic system efficiently promotes the allylation reaction in DMF to produce homoallylic alcohols in high yield.