Synthesis of Novel 1H‐Imidazol[1,2‐a]Indeno[2,1‐e]Pyridine‐6(5H)‐Ones Derivatives via a One‐Pot Four‐Component Condensation Reaction

1H‐imidazol[1,2‐a]indeno[2,1‐e]pyridine‐6(5H)‐ones derivatives were synthesized in a one‐pot four‐component condensation of corresponding aldehydes, 1,3‐indandione, diamine, and nitro ketene dithioacetal using KAl(SO₄)₂·12H₂O (alum) as nontoxic, reusable, inexpensive and easily available catalyst in good to excellent yields. This green protocol provides a powerful entry into fused polycyclic structures related to bioactive heterocycles.     

Facile entry to polycyclic indolylhydroquinoline skeletons via tandem C-alkylation and intramolecular S-alkylation

An efficient, single step synthesis of hitherto unknown indole-annulated pentacyclic indolylhydroquinolines via tandem C-alkylation and intramolecular S-alkylation of indolin-2-thiones with N-alkylquinolinium salts in excellent yields (83-95%) is reported. This facile approach provides a powerful entry into polycyclic structures containing nitrogen and sulfur related to alkaloids. The structure of the product was determined by Röntgen crystal structure analysis.     

Anomeric effect for a 2,5,7‐triazabicyclo[2.2.1]heptane derivative

A new member of the polyazapolycyclic family of compounds, namely N³,N⁶,2,5,7‐pentaphenyl‐2,5,7‐triazabicyclo[2.2.1]heptane‐3,6‐diamine xylene solvate, C₃₄H₃₁N₅·C₈H₁₀, was synthesized for the first time and the crystal structure is reported. There are no hydrogen bonds joining the molecules. All four chiral C atoms have the same absolute configurations. With regard to the four N—C—N groups, anomeric effects are observed to cause a reduction of C—N bond length and N‐atom pyramidality.     

Stationary twists and energy minimizers on a space of measure preserving maps

Let be a bounded Lipschitz domain, a suitably quasiconvex integrand and consider the energy functional

over the space of measure preserving maps

In this paper we discuss the question of existence of multiple strong local minimizers for over . Moreover, motivated by their significance in topology and the study of mapping class groups, we consider a class of maps, referred to as twists, and examine them in connection with the corresponding Euler–Lagrange equations and investigate various qualitative properties of the resulting solutions, the stationary twists. Particular attention is paid to the special case of the so-called p-Dirichlet energy, i.e., when .     

A Facile Synthesis of Bridged Polycyclic Naphthooxazocine Skeletons: Eight‐Membered‐Ring Constructions via Tandem Dinucleophilic Addition of Naphthalenols to Quinolinium Salts

The efficient synthesis of bridged polycyclic naphthooxazocines 3 via addition of naphthalenols 1 as a bis‐nucleophile to N‐alkylquinolinium salts 2 is described (Scheme 1 and Table 2). This new approach provides a powerful entry into polycyclic structures containing bicyclic N,O‐acetals related to bioactive compounds.     

Study on the interaction between dinaphthosulfide-substituted macrocyclic diamides and some metal ions: experimental measurements vs. quantum mechanical calculations

Complexation properties of dinaphthosulfide-substituted macrocyclic diamides 1 and 2 with some metal cations that have been obtained by conductometric method are described with quantum mechanics calculations. To do this, the most stable structures of ligands, Hg²⁺-ligand complexes, ligand-MeOH and ClO₄ ^?–MeOH are optimized at HF/Lanl2dz level of theory and the most important interactions are analyzed by atoms in molecules (AIM) theory. These calculations predict the existence of strong interaction between Hg²⁺ cation and ligands 1 and 2, particularly, S–Hg²⁺ interaction. The different conductometric behaviors of complexation of ligands 1 and 2 with metal ions are interpreted on the basis of the calculated intramolecular hydrogen bonds in ligands and intermolecular hydrogen bonds between ligands and methanol as a solvent and perchlorate as a counter ion. In addition, binding energies between Hg²⁺ and ligands are also calculated by HF/Lanl2dz level of theory. Results show that all theoretical predictions are in line agreement with the experimental data.     

On stress matrices of (d + 1)-lateration frameworks in general position

Let (G, P) be a bar framework of n vertices in general position in ${\mathbb{R}^d}$ , for d ≤ n ? 1, where G is a (d + 1)-lateration graph. In this paper, we present a constructive proof that (G, P) admits a positive semidefinite stress matrix with rank (n ? d ? 1). We also prove a similar result for a sensor network, where the graph consists of m(≥ d + 1) anchors.     

Hydrodynamic Characteristics and Adsorption Particularity of Nanobiological Feedstock Along the Bed Height in a Novel Chromatography Column

Expanded bed adsorption (EBA) is a practical method for the separation of nanoparticulates. In order to analysis the local hydrodynamic and adsorption behavior of nanoparticle (NP)-based biological feedstock, a modified Nano Biotechnology Group EBA column with a 26-mm inner diameter was used to withdraw liquid from different axial positions of the column. Fabricated egg albumin (EA) NPs with an average size of 70 nm were employed as a model system and viral size/charge mimic to assess the relationship between hydrodynamic and adsorption performance of NPs at the different column regions. The effects of influential factors, including flow velocity and initial concentration of NPs, on NP hydrodynamic behavior and adsorption kinetics along the bed height were investigated. NP hydrodynamic studies confirmed that non-uniform behavior dominated the system and a decreasing trend of liquid mixing/dispersion with increase of bed height was observed in this column. The results demonstrated an increase in the mixing/dispersion at certain bed heights with the increase in both the velocity and feed initial concentration. Breakthrough curves were measured at various column points to determine the adsorption performance [dynamic binding capacity (DBC) and yield] in different bed positions/zones. Yield and DBC of NPs were improved along the bed height, whereas liquid velocity had the opposite effect. Increasing the initial concentration of NPs enhanced only the DBC. Separation of EA NPs under optimal conditions was 87 %, which is an excellent result for a one-pass frontal chromatography method.

     

Spherical twists, stationary paths and harmonic maps from generalised annuli into spheres

Let X ì \mathbb Rⁿ{{\bf X} \subset {\mathbb R}^n} be a generalised annulus and consider the Dirichlet energy functional

Dynamic response of cable-stayed bridges to moving vehicles using the structural impedance method

The importance of dynamic interactions between cable-stayed bridges and heavy moving vehicles, such as trucks and locomotives, has been recognised by bridge engineers for a long time. A structural impedance algorithm is developed for analysing the dynamic response of cable-stayed bridges subjected to traversing vehicles. The bridge deck is modelled as an elastic plate, and the cables are idealised as springs for simplicity. The vehicles are modelled as a series of masses with suspension systems moving with different speeds and accelerations. A comprehensive computer program, CABLESIM, is developed for the static and dynamic analyses of a cable-stayed bridge. The accuracy of the numerical procedure and its computer implementation is verified with the available analytical and experimental results. A parametric study is conducted to investigate the effects of vehicle velocity, girder depth, different types of cable arrangements, and traffic load on the dynamic response of the deck. The numerical results are expected to be important in assessing the dynamics of cable-stayed bridge components and in determining the safety and allowable traffic conditions.