Synthesis of 3-alkenylated indole and bis(indol-3-yl) derivatives catalyzed by sulfonic acid-functionalized ionic liquid under ultrasound irradiation

A simple and efficient protocol has been developed for the synthesis of 3-alkenylated indoles and bis(indol-3-yl) derivatives by sulfonic acid-functionalized ionic liquid-catalyzed reaction of indole with 1,3-diketones/3-ketoesters under solvent-free ultrasound irradiation. Good to excellent yields (68–94%) are obtained in ultrasonication. The product of reaction is dependent on the substituent at C-2 position of indole. The catalyst is reusable and recyclable up to four cycles without significant loss of its catalytic activity. Compared with conventional heating, sound wave activation has the considerable advantages such as shorter reaction time, easy work-up, higher yields, and mild conditions.     

Antinociceptive and anthelmintic activity of Canna indica

Dried, coarsely powdered leaves, flowers, rhizomes and seeds of Canna indica were successively extracted with benzene and methanol in Soxhlet apparatus. The effect of benzene and methanol extracts of various parts of C. indica on nociceptive response using writhing test and hot plate method in mice was examined. All the extracts of C. indica showed significant central and peripheral analgesic activity in hot plate method and acetic acid-induced writhing test, respectively, at the dose of 50 mg kg(-1) intraperitoneally. Methanolic extract of leaves of C. indica showed highest increase in reaction time in hot plate method while benzene extract of leaves of C. indica showed more inhibitory effect on writhing induced by acetic acid. Anthelmintic activity of these extracts was evaluated on Pheritima posthuma. Results showed that the methanolic extract of rhizomes of the plant took less time to cause paralysis of the earthworms.     

A Crystal Structure of a Functional RNA Molecule Containing an Artificial Nucleobase Pair

As one of its goals, synthetic biology seeks to increase the number of building blocks in nucleic acids. While efforts towards this goal are well advanced for DNA, they have hardly begun for RNA. Herein, we present a crystal structure for an RNA riboswitch where a stem C:G pair has been replaced by a pair between two components of an artificially expanded genetic‐information system (AEGIS), Z and P , (6‐amino‐5‐nitro‐2(1H)‐pyridone and 2‐amino‐imidazo[1,2‐a]‐1,3,5‐triazin‐4‐(8H)‐one). The structure shows that the Z : P pair does not greatly change the conformation of the RNA molecule nor the details of its interaction with a hypoxanthine ligand. This was confirmed in solution by in‐line probing, which also measured a 3.7 nM affinity of the riboswitch for guanine. These data show that the Z : P pair mimics the natural Watson–Crick geometry in RNA in the first example of a crystal structure of an RNA molecule that contains an orthogonal added nucleobase pair.     

A study of anhydrocelluloses--is a cellulose structure with residues in a 1C4-conformation more prone to hydrolysis?

A study of the effect of introduction of 3,6-anhydroglucose residues in the cellulose structure on glycoside hydrolysis rate was performed. A cellotetrose with an 3,6-anhydroglucose as the third residue was synthesised. Acidic hydrolysis of this tetrasaccharide showed that hydrolysis of the 3,6-anhydro-β-D-glucoside linkage was 31.400 times faster than hydrolysis of cellobiose. A series of different 3,6-anhydrocelluloses with different degree of substitution were prepared by tosylation of cellulose with varying amounts of tosyl chloride in dimethylacetamide and subsequent treatment with sodium hydroxide. Anhydrocelluloses with degrees of substitution of 0.02, 0.07, 0.31 and 0.74 were obtained. The anhydrocelluloses were subjected to acidic hydrolysis in 2.0 M aqueous HCl and the rate of hydrolysis monitored by ion chromatography analysis of the amount of glucose and/or cellobiose formed. All 3,6-anhydrocelluloses hydrolyzed with a faster rate than cellulose, but the anhydrocellulose with a low degree of substitution (ds = 0.07) hydrolyzed fastest which was 90 times faster than cellulose.     

Stereo-controlled approach to pyrrolidine iminosugar C-glycosides and 1,4-dideoxy-1,4-imino-l-allitol using a d-mannose-derived cyclic nitrone

Intramolecular N-alkylation of 2,3-O-isopropylidene-5-O-methanesulfonyl-6-O-t-butyldimethylsilyl-d-mannofuranose-oxime 7 afforded a five-membered cyclic nitrone 9, which on N–O bond reductive cleavage followed by deprotection of –OTBS and acetonide functionalities gave 1,4-dideoxy-1,4-imino-l-allitol (DIA) 3. Addition of allylmagnesium chloride to nitrone 9 afforded α-allylated product 10a in high diastereoselectivity providing an easy entry to N-hydroxy-C1-α-allyl-substituted pyrrolidine iminosugar 4a after removal of protecting group, while N–O bond reductive cleavage in 10a afforded C1-α-allyl-pyrrolidine iminosugar 4b.     

Luminescence characteristics of Na21(SO4)7F6Cl:Cu+ phosphor

Copper-doped Na₂₁(SO₄)₇F₆Cl phosphor was synthesized via the conventional wet chemical method. The synthesis was carried using CuCl₂ and Cu (NO₃)₂·3H₂O as dopants in two different steps successively. The formation and phase purity of the compound were revealed by the X-ray diffraction pattern. Functional groups of the prepared phosphor were observed in the FT–IR spectrum. The emission along with excitation spectra were followed to explore the luminescence attributes. Photoluminescence (PL) emission spectrum of the material synthesized using CuCl₂ as the dopant was observed at 358?nm due to 3d^l0?3d⁹4s transitions when excited around 247?nm for various copper concentrations. Efficient blue emissions were obtained at peaks 423 and 469?nm for materials synthesized using Cu (NO₃)₂·3H₂O as the dopant, when monitored at 357?nm excitation. The Commission Internationale de I’Eclairage chromaticity coordinates for different copper concentrations were calculated for the emission around 423?nm. TL glow curves of Na₂₁(SO₄)₇F₆Cl:Cu phosphor for different dopant concentrations, irradiated with 100?Gy gamma dose, were studied and hence the trap parameters, namely order of kinetics (b), activation energy (E) and frequency factor (s) associated with the most intensive glow peak of Na₂₁(SO₄)₇F₆Cl:Cu phosphor were determined by using Chen’s Peak shape method. The results indicate that Na₂₁(SO₄)₇F₆Cl:Cu⁺ is a potential novel blue-emitting lamp phosphor and may be quite suitable for use in dosimetry of ionizing radiations.     

Fast separation and sensitive detection of carcinogenic aromatic amines by reversed-phase micro-liquid chromatography coupled with electrochemical detection

A micro-LC method was developed for the fast and sensitive analysis of aromatic amines by electrochemical detection. The chromatographic separation of nine carcinogenic aromatic amines was performed on an ABZ + PLUS column with detection limits up to pM L(-1) levels. Mobile phase comprised of methanol-acetate buffer of pH 5 (45:55, v/v) used at a flow rate of 0.2 ml min(-1). The detection was performed with a 6 mm glassy carbon electrode at an applied potential of 0.8 V versus Ag/AgCl. An intraday RSD for retention time and peak area were between 0.22% and 0.73% and 1.86% and 4.03%, respectively. The interdays RSD for retention time and peak area were between 0.47% and 1.35% and 2.04% and 4.42%, respectively. The applicability of the assay has been demonstrated by analyzing these aromatic amines in lake water and synthetic food colour additives. A comparison is given between electrochemical and UV detection.     

Equilibrium constants of UO 2 2+ , Cu2+ with dicarboxylic acids in dioxane-water mixtures

The interactions of uranyl and copper ions with dicarboxylic acids such as succinic, itaconic, adipic and malonic acids have been investigated in 20, 40, 60 and 80% (v/v) dioxane-water mixtures at 30°C and 0·06 ionic strength by Calvin-Bjerrum titration technique. UO ₂ ²⁺ , Cu²⁺ form only 1:1 complexes with succinic, itaconic and adipic acids and both 1:1 and 1:2 with malonic acid in the pH range 2·5–5. The plots of pK/log K vs mole fraction gave linear while those with 1/D gave non-linear. The complexation equilibria: are proposed. The radius of anionic ligand is calculated from Born equation and attempts are made to understand the medium effect on the pK values.     

Inherent stability testing of empagliflozin in the presence of metformin HCl by HPTLC and characterization of degradation products of empagliflozin by LC–ESI–QTOF–MS/MS

JPC – Journal of Planar Chromatography – Modern TLC - A successful attempt has been made to develop and validate a stability-indicating high-performance thin-layer chromatography...     

Designing of LaCrO3 − TiO2 nanocomposites p: n heterojunction-based sensor material for the selective detection of volatile petrol vapors (PV) and CO2 gas vapors

In the present research TiO₂ modified LaCrO₃ nanostructure has been designed by simple sol-gel method. The thick films of TiO₂ with different concentrations with LaCrO₃ were fabricated by using screen printing methodology. In present study, the structural properties of TiO₂ doped LaCrO₃ were confirm by using X-ray diffractometer (XRD). While the morphological properties and surface characteristics of fabricated material analyzed using scanning electron microscopy (SEM). The energy dispersive spectroscopy (EDS) was utilized for chemical composition of the prepared material. Transmission electron microscopy (TEM) confirms the orthorhombic crystal lattice structure and morphology of Ti-doped LaCrO₃. While, Fourier transform infrared (FT-IR) spectroscopy was used to investigate the M ? O bonding vibrational stretching frequencies of LaCrO₃ and TiO₂ materials. The zeta potential was recorded for stability of all Ti doped LaCrO₃ nanostructures. The Brunauer-Emmett-Teller (BET) was analyzed for surface area and pore diameter parameters of the fabricated materials. The fabricated materials were checked for application as a sensor for different pollutant gases like Ethanol, CO₂, NO₂, and petrol vapors. The sensor demonstrates the sensitivity for petrol vapors at 150°C for 0.3 M% TiO₂ doped LaCrO₃. And exceptionally 0.5 M% TiO₂ doped LaCrO₃ sensor showed better response for CO₂. The reproducibility confirms the stability of 0.3 M % TiO₂ doped LaCrO₃ sensor and 0.5 M % TiO₂ doped LaCrO₃ sensor. The rapid response and recovery were recorded for both the sensors viz. 0.3 M % and 0.5 M % TiO₂ doped LaCrO₃.