Microwave-Induced One - Pot Synthesis of some new Spiro [Indoline-3,2′-Thiazolidine]-2,4′(1H)-Diones and Bis [Spiro [Indoline -3,2′-Thiazolidine]-2,4′(1H)-Diones]

The title compounds have been obtained thermally and under microwave irradiation by condensation of isatin, aromatic amines and mercaptoacetic acid in good to excellent yields without isolating the imine intermediates.     

Hydration strongly affects the molecular and electronic structure of membrane phospholipids

We investigate the structure and electronic properties of phosphatidylcholine (PC) under different degrees of hydration at the single-molecule and monolayer type level by linear scaling ab initio calculations. Upon hydration, the phospholipid undergoes drastic long-range conformational rearrangements which lead to a sickle-like ground-state shape. The structural unit of the tilted gel-phase PC appears to be a water-bridged PC dimer. We find that hydration dramatically alters the surface potential, dipole and quadrupole moments of the lipids and consequently guides the interactions of the lipids with other molecules and the communication between cells.     

Spirooxindoles: reaction of 2,6-diaminopyrimidin-4(3H)-one and isatins

A simple and efficient cyclocondensation reaction of 2,6-diaminopyrimidin-4(3H)-one and isatins for the synthesis of spiro[pyrimido[4,5-b]quinoline-5,5′-pyrrolo[2,3-d]pyrimidine] and spiro[indoline-pyrido[2,3-d:6,5-d′]dipyrimidine] derivatives is reported.     

DFT Study of Endohedral Atoms Effect on Electrophilicity of B16N16 Boron Nitride Nanocage: Comparative Analyses

Endohedral derivatives of B₁₆N₁₆ nanocage (M@B₁₆N₁₆, M?=?Li⁺, Na⁺, K⁺, Mg²⁺, Ne, O^2?, S^2?, F^?, Cl^?) and its iso-electronic fullerne M@C₃₂ have been employed to investigate the relation between the trapped atom/ion and electrophilicity of the B₁₆N₁₆ and C₃₂ nanocages. The electrophilicity index, ??, of these endohedral nanocages has been evaluated from the ionization potential and the electron affinity computed by vertical ionization/affinity at the B3LYP/6-311++G(df,pd) level. Obtained results illustrate that the nature of trapped atom/ion affects HOMO-LUMO band gap, global electrophilicity indices and reactivity of B₁₆N₁₆ and C₃₂ nanocages. Encapsulation B₁₆N₁₆ with different atom/ions may be a possible method for modifying HOMO-LUMO energy gap, electrophilicity and so chemical characteristics of and C₃₂ nanocages.     

Total synthesis of homalicine and its related dihydro aglycon

The condensation of homophthalic acid (1) with 3‐methoxybenzoyl chloride, followed by demethylation gave 3‐(3‐hydroxyphenyl)isocoumarin (3b). Reaction of (3b) with α‐tetraacetobromo glucose yielded tetraacetylhomalicine (3d), which was deacetylated to homalicine (3e).     

On Matrix-Geometric Solution of Nested QBD Chains

In this paper, a generalization of the level dependent Quasi-Birth-and-Death (QBD) chains is presented. We analyze nested level dependent QBD chains and provide the complete characterization of their fundamental matrices in terms of minimal non-negative solutions of a number of matrix quadratic equations. Our results provide mixed matrix-geometric solution for the stationary distribution of nested QBD chains. Applications in overload control in communication networks are also discussed.     

One Pot Synthesis of Some New Spiro[3H-Indol-3,5′(4′H)-[1,2,4] Oxadiazol]-2-Ones and Bis[Spiro[3H-Indol-3,5′(4′H)-[1,2,4] Oxadiazol]-2-Ones]

A facile preparation of the title compound by 1,3-dipolar cycloaddition reaction of benzonitrile oxides with isatin imines or isatin diimines, in excellent yield, are reported.     

The impact of in-line coagulant addition on fouling potential of secondary effluent at a pilot-scale immersed ultrafiltration plant

The impact of in-line coagulation pre-treatment of secondary effluent on the operation of an immersed hollow-fibre ultrafiltration membrane pilot was evaluated as part of a larger study on optimising phosphorus removal. The efficacy of alum and ferric chloride was investigated, with an emphasis on alum use. Both coagulants were found to shift the particle-size distribution of organic matter in the feed towards larger fractions, with a notable reduction in colloidal matter. This was reflected in a reduction of both average daily transmembrane pressure increases, as well as a reduction of transmembrane pressure increases within backpulse intervals. Fouling reduction was observed with both lower and higher membrane packing density modules (membrane surface areas of 55.7 and 62.7 m²/module). The results of one-way analysis of variance (ANOVA) testing indicate that for this pilot system, chemical pre-treatment and solids concentrations in the feed water played a statistically significant role in determining transmembrane pressure variations. Membrane packing density and membrane production method did not exhibit a statistically significant effect on transmembrane pressure under the conditions of this study.     

Global Reactivity of Heterostructure Armchair BC2N‐(4,4) Nanotubes: A Density Functional Theory Investigation

Electronic structures of three types of heterostructure armchair BC₂N nanotube besides armchair (4,4)CNT and (4,4)BNNT were calculated by the B3LYP method of density functional theory. The reactivities of nanotubes were discussed by means of obtained vertical ionization potentials and electron affinity potentials. The corresponding electrophilicity values are well correlated with those obtained from the HOMO and LUMO energies of the nanotubes. The good linear correlation found between ω(I,A) and ω(H,L) allows to confirm the use of the easily available B3LYP/6‐31G(d) HOMO and LUMO energies to obtain reasonable values of the global electrophilicity index of nanotubes at a lower computational cost. © 2013 Wiley Periodicals, Inc. Heteroatom Chem 24:168–173, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21078     

Highly Regioselective and Diastereoselective,One‐Pot,Four‐Component Synthesis of Novel Spiroindenoquinoxalineindolizidine Derivatives

A one‐pot, four‐component procedure for the synthesis of novel spiroindenoquinoxalineindolizidines with high regioselectivity and diastereoselectivity from the 1,3‐dipolar cycloaddition of azomethine ylides, generated from indenoquinoxalines and pipecolinic acid, and chalcones is described. The reaction occurs under reflux of ethanol as a green solvent and in the absence of any catalyst. The cycloadducts are obtained purely without future purification. The regiochemistry and stereochemistry of resultant cycloadducts have been determined by several 2D‐NMR spectroscopic techniques and X‐ray single crystal diffraction.