A novel hydrophobic fluorous ionic liquid for ligand-free Mizoroki–Heck reaction

Mizoroki–Heck reaction is carried out in a novel hydrophobic fluorous ionic liquid which was catalyzed by Pd-nanoparticles formed in situ from Pd(OAc)₂ used in the reaction. This reaction is operable under mild, aerobic, and ligand-free conditions in excellent yields. Aryl iodides, bromides as well as chlorides can be used showing its versatility. The key feature of the system is that catalyst along with ionic liquid can be reused at least five times with superior activity.     

Comparison of transfer factors of <Superscript>137</Superscript>Cs from soil to leafy vegetables in pot experiment and ambient environment

The paper deals with the transfer factors (TF) generated for a few varieties of leafy vegetables (spinach, fenugreek, and amaranths) consumed by the locals around Tarapur atomic power station environment in India. The soil and leafy vegetable samples collected from the ambient environment of nuclear site were used for the determination of the TFs and they were compared with TFs generated from pot experiments under controlled conditions for ¹³⁷Cs. The activity of ¹³⁷Cs in soil and each vegetable was determined by gamma spectrometry using HPGe detector (35 and 160% relative efficiency) and was reported on dry weight basis for both ambient environment and pot samples. The radioactive effluent containing ¹³⁷Cs (pH ~7) from nuclear power station was used to spike the soil for pot (size 90 cm × 45 cm × 42 cm) experiment. The TFs obtained for ambient environment and pot experiment were found to be in the range of 0.035–0.592 and 0.0054–0.29, respectively. It is observed that TFs of ambient environment are in good agreement with those obtained in the pot experiment conducted under controlled conditions. Further, the observed TF values at Tarapur nuclear site are comparable with the range of typical IAEA transfer factor values for general leafy vegetation (0.11–2.9) for tropical environment.     

Effect of gamma irradiation on antioxidant activity of Amoora rohitaka

The effect of a medium dose of gamma radiation on antioxidant activity of Amoora rohitaka was studied. Radiation doses were 0, 1, 3 and 5?kGy. Antioxidant activity was screened by using different assay. With increasing dose the formation of Maillard reaction products (MRPs) contributes to the increase in the antioxidant activity. MRPs are formed as a result of Maillard reaction. In ABTS [2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid di-ammonium salt] assay, ethanol extract showed increase in scavenging activity. It also showed a marked increase in polyphenolic contents. The present study reveals that gamma irradiation can be an efficient process to increase antioxidant activity of Amoora rohitaka.     

Antioxidant activities of phenols in different solvents using DPPH assay

Studies on the antioxidant activity of two model phenols containing either an electron withdrawing (p-nitrophenol) or electron donating (p-aminophenol) group and p-hydroxyacetophenone in different solvents are reported using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical assay by spectrophotometry and stopped-flow techniques. The second-order rate constants measured with p-nitrophenol were found to be (1.2–5.5) × 10⁻² dm³ mol⁻¹ s⁻¹ but the DPPH radical reacts much faster with p-aminophenol (k = 0.5–1.1 × 10⁴ dm³ mol⁻¹ s⁻¹). The normal kinetic solvent effect in H atom transfer was seen in the case of p-nitrophenol with the solvent independent rate constant k _o = 0.1 dm³ mol⁻¹ s⁻¹. The IC₅₀ values in p-nitrophenol are similar to those measured in p-hydroxyacetophenone. On the other hand, much lower IC₅₀ values of more than four orders of magnitude with p-aminophenol were observed. This work demonstrates that the phenol with the electron donating –NH₂ substituent is a better antioxidant.     

Synthesis of (+)-isofagomine

The synthesis of (+)-isofagomine 1 using 4-pentenol 3 as a chiral precursor is described herein.     

Facile Synthesis of Nitriles from Aromatic Aldehydes Using DMSO‐I2

Nitriles have been prepared from different aromatic aldehydes by a one‐pot process using hydroxylamine hydrocloride and molecular iodine in the presence of dimethylsulphoxide.     

Conformational Transitions in <Emphasis Type="Italic">Ariesaema curvatum</Emphasis> Lectin: Characterization of an Acid Induced Active Molten Globule

Biophysical characterization of a lectin from Ariesaema curvatum (ACL) was carried out using steady state as well as time resolved fluorescence and CD spectroscopy under various denaturing conditions. An intermediate with altered tryptophan microenvironment was detected in the phase diagram, which exibited pronounced secondary structure and hemagglutinating activity in presence of 0.25 M Gdn–HCl. An acid induced molten- globule like structure possessing activity and higher thermostability was detected. Transition to the molten globule state was reversible in nature. The lectin retained hemagglutinating activity even after incubation at 95 °C. Both chemical and thermal unfolding of the lectin were found to consist of multistate processes. Fluorescence quenching of ACL was strong with acrylamide and KI. The single tryptophan was found to be surrounded by high density of the positively charged amino acid residues as shown by a ten fold higher K_sv for KI compared to that for CsCl. The average lifetime of tryptophan fluorescence increased from 1.24 ns in the native state to 1.72 ns in the denatured state.