Synthesis and Ameliorative Effect of Isatin–Mesalamine Conjugates on Acetic Acid‐induced Colitis in Rats

A series of new isatin–mesalamine conjugates ( 9a – g ) were synthesized via conjugation of isatin ( 3a ) and its derivatives ( 3b – 3d , 4 , 5 , and 6 ) with mesalamine ( 7 ) by using chloroacetyl chloride as a bifunctional linker. Compounds 3a – 3d were prepared by employing Sandmeyer reaction. Compounds 4 , 5 , and 6 were obtained from isatin ( 3a ) via previously reported methods. The synthesized compounds were characterized by IR, mass, ¹H NMR, and ¹³C NMR spectral techniques. Synthesized compounds ( 3a – d , 4 , 5 , 6 , and 9a – g ) were evaluated for in vitro antioxidant activity by DPPH assay method using ascorbic acid as standard. Hybrids 9b (IC₅₀ = 368.6 ± 3.5 μM) and 9f (IC₅₀ = 335.1 ± 2.9 μM) showed better antioxidant activity than its parent compounds such as 3a (IC₅₀ = 556.8 ± 2.9 μM), 5 (IC₅₀ = 511.9 ± 3.6 μM), and 7 (IC₅₀ = 768.9 ± 2.7 μM). Acetic acid‐induced ulcerative colitis in rat model was chosen to examine the antioxidant potential of the synthesized hybrids ( 9b and 9f ) in the amelioration of ulcerative colitis. Colonic myeloperoxidase and malondialdehyde enzymes were used as biomarkers of anti‐ulcerative colitis activity. In the present study, hybrids 9b and 9f reduced the levels of colonic myeloperoxidase and malondialdehyde enzymes significantly (p < 0.05) when compared with control (colitic), at a dose (0.03 mM/12.5 mg/kg b.w. p.o.) (50%) less than that of its parent moieties mesalamine (0.16 mM/25 mg/kg) and isatin (0.16 mM/25 mg/kg). Thus, the molecular hybridization was proved to be significant in enhancing the activity of hybrids 9b and 9f by reducing the dose.     

A note on random fields forming conditional bases

We study properties of random fields that form conditional bases and their applications in spatial statistics.     

Configuration biased Monte Carlo and Brownian dynamics simulations of semiflexible polymers in extensional flows

Configuration Biased Monte Carlo (CBMC) and Non-Equilibrium Brownian Dynamics (NEBD) simulations are used to understand the dynamics of semi-flexible macromolecules undergoing extensional flow. The mathematical model utilizes a discretized version of the Kratky-Porod wormlike (or persistent) chain as the building block, and using kinetic theory, generalized to include flow. In steady, potential flows, the solution of the Fokker-Planck equation exists and is used in the generation of trial and acceptance moves in the CBMC scheme. For the NEBD, the Fokker-Planck equation is converted to a Stochastic Differential Equation (SDE) from which the simulation algorithm is obtained. Various conformational quantities are monitored, under both steady-state and transient conditions, with the primary independent variable being the flexibility parameter β, the bending constant of the chain. It is found that the model is able to describe qualitatively many of the experimentally observed effects in such systems. In particular, we find that there is a direct link between the molecular flexibility and its birefringence response in an elongational flow field. We are able to draw conclusions by considering the behavior of molecular-conformational quantities such as the radius of gyration and the moment of inertia.     

First Cp*Co(III)-catalyzed Mizoroki-Heck coupling reactions of alkenes and aryl bromide/iodide

A Cp*Co(CO)I₂ catalyzed Mizoroki-Heck coupling of alkenes and aryl halide is established at feasible reaction conditions. The Cp*Co(III) catalyst excellently work to couple the aryl iodide and alkene, and produce up to 94% yield of the coupling product. In case of the coupling of aryl bromide and alkene, slightly reduced activity of the catalyst was observed, and moderate to good yield of the product was obtained. Apart from functionally different styrene, the catalyst was also able to activate the acrylates, which seems difficult to be activated by other reported metal complexes. The coupling proposed herein is tolerant a wide variety of aryl halides, stryenes, and acrylates enable to form CC bond using inexpensive metal in catalysis. Hence, the present catalyst is highly economical, consists a non-endangered metal and is highly efficient for Heck coupling reaction. Moreover, the cobalt metal in high oxidation state (+3) is not much explored for the CC cross-coupling reactions.     

DFT and MD simulations and molecular docking of co-crystals of octafluoro-1,4-diiodobutane with phenazine and acridine

Structural Chemistry - Co-crystals are of immense applications in crystal engineering and pharmaceutical chemistry. Co-crystals of octafluoro-1,4-diiodobutane with phenazine (PHEF) and acridine...     

Stability of Double-Diffusive Natural Convection in a Vertical Porous Layer

Transport in Porous Media - The stability of double-diffusive buoyant flow in a vertical layer of Darcy porous medium whose boundaries are held at different constant temperatures and solute...     

Corrosion resistance of sol–gel alumina coated Mg metal in 3.5 % NaCl solution

Journal of Sol-Gel Science and Technology - This investigation describes the potential of sol–gel derived alumina coating on the corrosion resistance of magnesium metal in 3.5&nbsp;% NaCl...     

Impact of intermolecular vibrational coupling effects on the sum-frequency generation spectra of the water/air interface

ABSTRACT

We have examined the impact of intermolecular vibrational coupling effects of the O-H stretch modes, as obtained by the surface-specific velocity-velocity correlation function approach, on the simulated sum-frequency generation spectra of the water/air interface. Our study shows that the inclusion of intermolecular coupling effects within the first three water layers, i.e. from the water/air interface up to a distance of 6?Å towards the bulk, is essential to reproduce the experimental SFG spectra. In particular, we find that these intermolecular vibrational contributions to the SFG spectra of the water/air interface are dominated by the coupling between the SFG active interfacial and SFG inactive bulk water molecules. Moreover, we find that most of the intermolecular vibrational contributions to the spectra originate from the coupling between double-donor water molecules only, whereas the remaining contributions originate mainly from the coupling between single-donor and double-donor water molecules.     

Novel one pot synthesis of substituted quinazolin-4(3H)-ones and pyrazolo[4,3-d]pyrimidin-7(6H)-ones using copper iodide,azides and terminal alkynes

A simple and highly efficient copper iodide catalyzed one-pot synthesis of 2-substituted quinazolin-4(3H)-ones have been developed from anthranilamide, terminal alkynes and azides. A wide variety of alkynes were screened to understand the scope of this methodology. This method has been extended for the synthesis of 5-substituted pyrazolo[4,3-d]pyrimidin-7(6H)-ones which are having potential applications in medicinal chemistry.