Synthesis and Crystal Structure Studies of Novel Bioactive Heterocycle: 7-Chloro-5-Cyclopropyl-9-Methyl-10-(2-Piperidin-1-yl-Ethyl)-5,10-Dihydro-4,5,6,10-Tetraaza-Dibenzo[a,d] Cyclohepten-11-One

Abstract  The compound, 7-chloro-5-cyclopropyl-9-methyl-10-(2-piperidin-1-yl-ethyl)-5,10-dihydro-4,5,6,10-tetraaza-dibenzo[a, d] cyclohepten-11-one, C₂₂H₂₆N₅ClO, crystallizes in the triclinic space group Pī with cell parameters a = 8.918(7) ?, b = 9.297(7) ?, c = 14.184(8) ?, V = 1095.98(1) ?³ and Z = 2. The final residual factor R ₁ = 0.0451. The structure exhibits intermolecular hydrogen bonds. The 2-piperidin-1-yl-ethyl ring adopts a chair conformation. The starting material used to synthesize the title compound is the intermediate compound of well known anti-HIV drug Nevirapine hence the title compound is having biological importance and hence this crystal structure will helps to structural characterization of the molecule and also for the molecular modeling it will helps for biological study. Graphical Abstract  The title compound 7-chloro-5-cyclopropyl-9-methyl-10-(2-piperidin-1-yl-ethyl)-5,10-dihydro-4,5,6,10-tetraaza-dibenzo[a, d] cyclohepten-11-one was synthesized by condensation of 7-chloro-5-cyclopropyl-9-methyl-5,10-dihydro-4,5,6,10-tetraaza-dibenzo[a, d] cyclohepten-11-one with 1-(2-chloro-ethyl)-piperidine hydrochloride in presence of anhydrous powdered potassium carbonate as base using N,N-dimethyl formamide as solvent and its crystal structure determined. The title compound derived from bioactive molecule and it is also having biological importance hence this crystal structure will helps for the structural characterization and the biological study of the novel molecule.      

Structural Conformation of a Novel 1-Benzhydrylpiperazine Derivative: 1-Benzhydryl-4-(toluene-4-sulfonyl)-piperazine

Abstract  The title compound 1-benzhydryl-4-(toluene-4-sulfonyl)-piperazine was synthesized and the structure was investigated by X-ray crystallography. The title compound, C₂₄H₂₆N₂O₂S crystallizes in the monoclinic crystal class in the space group P2₁/c with cell parameters a = 13.5800(10) ?, b = 8.9630(7) ?, c = 18.9040(10) ?, β = 106.851(3)°, Z = 4 and V = 2202.1(3) ?³. The structure has been solved by direct methods and refined to R ₁ = 0.0468 for 3174 observed reflections I > 2σ(I). The structure reveals that the piperazine ring is in a chair conformation. The geometry around the S atom is a distorted tetrahedron. Graphical Abstract  The title compound 1-benzhydryl-4-(toluene-4-sulfonyl)-piperazine was synthesized and the structure was investigated by X-ray crystallography. The title compound, C₂₄H₂₆N₂O₂S crystallizes in the monoclinic crystal class in the space group P2₁/c with cell parameters a = 13.5800(10) ?, b = 8.9630(7) ?, c = 18.9040(10) ?, β = 106.851(3)°, Z = 4 and V = 2202.1(3) ?³. The structure has been solved by direct methods and refined to R ₁ = 0.0468 for 3174 observed reflections I > 2σ(I). The structure reveals that the piperazine ring is in a chair conformation. The geometry around the S atom is a distorted tetrahedron.

On network form and function

Moving from the observation that drainage network configurations minimizing total energy dissipation are stationary solutions of the general equation describing landscape evolution, we review theoretical and observational evidence on river patterns and their scale-invariant structure. Exact results complemented by numerical annealing of the basic equation in the presence of additive noise suggest that configurations at (or very close to) the global minimum of energy dissipation differ from dynamically accessible states, which have rather different scaling properties and conform much better to natural forms. Thus we argue that, at least in the fluvial landscape, Nature works through imperfect searches for dynamically accessible optimal configurations. We also show that optimal networks are spanning loopless configurations only under precise physical requirements. This is stated in a form applicable to generic networks, suggesting that other branching structures occurring in Nature (e.g. scale-free and looping) may possibly arise through optimality to selective pressures. Indeed, we show that this is the case.     

Carbon-supported Pd-Co as cathode catalyst for APEMFCs and validation by DFT

Carbon supported PdCo catalysts in varying atomic ratios of Pd to Co, namely 1 : 1, 2 : 1 and 3 : 1, were prepared. The oxygen reduction reaction (ORR) was studied on commercial carbon-supported Pd and carbon-supported PdCo nanocatalysts in aqueous 0.1 M KOH solution with and without methanol. The structure, dispersion, electrochemical characterization and surface area of PdCo/C were determined by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Cyclic Voltammetry (CV), respectively. The electrochemical activity for ORR was evaluated from Linear Sweep Voltammograms (LSV) obtained using a rotating ring disk electrode. The catalysts were evaluated for their electrocatalytic activity towards oxygen reduction reaction (ORR) in Alkaline Polymer Electrolyte Membrane Fuel Cells (APEMFCs). PdCo(3 : 1)/C gives higher performance (85 mW cm(-2)) than PdCo(1 : 1)/C, PdCo(2 : 1)/C and Pd/C. The maximum electrocatalytic activity for ORR in the presence of methanol was observed for PdCo(3 : 1)/C. First principles calculations within the framework of density functional theory were performed to understand the origin of its catalytic activity based on the energy of adsorption of an O(2) molecule on the cluster, structural variation and charge transfer mechanism.     

Patterning of antibodies using flexographic printing

Antibodies were patterned onto flexible plastic films using the flexographic printing process. An ink formulation was developed using high molecular weight polyvinyl alcohol in carbonate-bicarbonate buffer. In order to aid both antibody adhesion and the quality of definition in the printed features, a nitrocellulose coating was developed that was capable of being discretely patterned, thus increasing the signal-to-noise ratio of an antibody array. Printing antibody features such as dots, squares, text, and fine lines were reproduced effectively. Furthermore, this process could be easily adapted for printing of other biological materials, including, but not limited to, enzymes, DNA, proteins, aptamers, and cells.     

Natural and synthetic solid polymer hybrid dual network membranes as electrolytes for direct methanol fuel cells

Hybrid dual-network membranes comprising chitosan (CS)–polyvinyl alcohol (PVA) networks crosslinked with sulfosuccinic acid (SSA) and glutaraldehyde (GA) and modified with stabilized silicotungstic acid (SWA) are reported for their application in direct methanol fuel cells (DMFCs). Physico-chemical properties of these membranes are evaluated using thermo-gravimetric analysis and scanning electron microscopy in conjunction with their mechanical properties. Based on water sorption and proton conductivity measurements for the membranes, the optimum content of 10 wt.% SWA in the membrane is established. The methanol crossover for these membranes are studied by measuring the mass balance of methanol using density meter and are found to be lower compared to Nafion-117 membrane. The membrane–electrode assembly with 10 wt.% stabilized SWA–CS–PVA hybrid membrane with SSA and GA as crosslinking agent delivers a peak power density of 156 mW cm⁻² at a load current density of 400 mA cm⁻² and 88 mW cm⁻² at a load current density of 300 mA cm⁻², respectively, in DMFC at 70 °C.     

Multi-component synthesis of 2-amino-6-(alkylthio)pyridine-3,5-dicarbonitriles using Zn(II) and Cd(II) metal-organic frameworks (MOFs) under solvent-free conditions

Multi-component synthesis of 2-amino-3,5-dicarbonitrile-6-thio-pyridines has been developed by using the reaction of aldehydes, malononitrile, and thiophenols in the presence of a Zn(II) or a Cd(II) metal-organic framework (MOF) as the heterogeneous catalyst. This protocol tolerates different functional groups on the substrates and does not require the use of any organic solvent. Moreover, the Zn(II) and Cd(II) MOF catalysts can be recovered and reused for a number of runs without loss of activity.     

1,4‐Dipolar Cycloaddition Reactions in Ionic Liquids: A Facile Synthesis of 9aH,15H‐[1]Benzopyrano[3′,2′: 3,4]pyrido[2,1‐a]isoquinolines (=9aH,15H‐Benzo[a][1]benzopyrano[2,3‐h]quinolizines)

Ionic liquids were found to be a suitable reaction medium for 1,4‐dipolar cycloaddition reactions of an isoquinoline, an activated alkyne, and a 4‐oxo‐4H‐1‐benzopyran‐3‐carboxaldehyde at room temperature to afford [1]benzopyrano‐pyrido‐isoquinoline (=9aH,15H‐benzo[a][1]benzopyrano[2,3‐h]quinolizine) derivatives selectively in good yields. The ionic liquid can be recovered and recycled in further runs without loss of activity.     

An efficient and simple method for synthesis of 2,2-disubstituted-2H-chromenes by condensation of a phenol with a 1,1-disubstituted propargyl alcohol using BF3·Et2O as the catalyst

An efficient and simple method for the synthesis of 2,2-disubstituted-2H-chromenes by one-step cyclocondensation of a phenol with a variety of 1,1-disubstituted propargyl alcohols using BF₃·Et₂O as the catalyst is described.     

An efficient synthesis of N-Boc-(2S,3S)-3-hydroxy-2-phenyl piperidine and N-Boc-safingol

An efficient strategy has been developed for the stereo selective synthesis of N-Boc-(2S,3S)-3-hydroxy-2-phenyl piperidine and N-Boc-safingol from benzaldehyde and N-Boc-imine.