A new modified Laplace decomposition method for higher order boundary value problems

In this article, we suggest modified Laplace decomposition method for analytical solution of eighth-order boundary value problems (BVPs). The numerical application indicates the effectiveness and stability of the proposed algorithm. The efficiency of proposed method is examined with the help of linear and nonlinear problems.     

Reliable controller for nonlinear multiagent system with additive time varying delay and nonlinear actuator faults

In this paper, the problem of nonlinear multiagent system with reliable control is taken into account. The prescribed system consists of additive time-varying delay, actuator faults with both linear and nonlinear functions. The main focus of this paper is to design a reliable control which guarantees the stability and consensus condition of the proposed system. Actuator faults with linear and nonlinear functions are considered in the control input. From the implementation of integral inequality, the linear matrix inequality format is derived by constructing the suitable Lyapunov Krasovskii functional for the specified system. Terminally numerical examples are furnished for the efficiency of the specified method.     

9-Acylation of 1-acyldipyrromethanes containing a dialkylboron mask for the alpha-acylpyrrole motif

1,9-Diacyldipyrromethanes are important precursors to porphyrins, yet synthetic access remains limited owing to (1) poor conversion in the 9-acylation of 1-acyldipyrromethanes and (2) handling difficulties because acyldipyrromethanes typically streak upon chromatography and give amorphous powders upon attempted crystallization. A reliable means for converting a dipyrromethane to a 1-acyldipyrromethane-dialkylboron complex was recently developed, where the dialkylboron (BR(2)) unit renders the complex hydrophobic and thereby facilitates isolation. Herein a refined preparation of 1,9-diacyldipyrromethanes is presented that employs the 1-acyldipyrromethane-BR(2) complex as a substrate for 9-acylation. The dialkylboron unit provides protection for the alpha-acylpyrrole unit. 9-Acylation requires formation of the pyrrolyl-MgBr reagent and the presence of 1 equiv of a nonnucleophilic base to quench the proton liberated upon alpha-acylation. Reaction of the 1-acyldipyrromethane-BR(2) complex (1 equiv) with mesitylmagnesium bromide (2 equiv) followed by the addition of an acylating agent (S-2-pyridyl thioate or acid chloride, 1.1 equiv) gives the corresponding 1,9-diacyldipyrromethane-BR(2) complex. The acylation method afforded 1,9-diacyldipyrromethane-BR(2) complexes with limited or no chromatography in yields of 64-92%. The 1,9-diacyldipyrromethane-BR(2) complexes are stable to routine handling, are readily soluble in common organic solvents, crystallize readily, and can now be prepared in multigram quantities through use of stoichiometric quantities of reagents.     

Solid-state structure of (+)-phendimetrazine bitartarate,an anorexic drug

The anorexic drug (+)-(2S, 3S, 4S)-phendimetrazine-2R, 3R)-bitartarate crystallized in the orthorhombic space groupP2₁2₁2₁ and at 293 Ka=7.7710(4),b=13.1379(7),c=15.9913(9) Å,V=1632.6(2) ų,Z=4,R(F)=0.062, andR _w (F)=0.026. A chair conformation 2,3-trans-1,4-oxazine ring with equatorially oriented 2-phenyl,3-methyl, andN-methyl substituents was found as predicted by an earlier reported solid-state CP-MAS¹³C-NMR investigation of crystalline (±)-phendimetrazine bitartarate. The O-CH₂-CH₂-N torsion angle of –58.4(6)° in the solid-state agrees nicely with the 56.0(7)° dihedral angle value estimated by¹H NMR spectroscopy for the major (equatorialN-methyl) phendimetrazine mesylate species in CD₂Cl₂ solution. A common solid-state conformational arrangement was found for (+)-phendimetrazine and a series of six other anorexic drugs structurally analogous to (+)-(2S, 3S)-pseudoephedrine. In this arrangement, NCH(Me)CPh has (S)-configuration, there is a (–)-gaucheMe-CH-C-Ph torsion angle, an antiperiplanarN-CH-C-Ph torsion angle, and the phenyl ring approximately eclipses the C-H bond of the attached carbon (e.g., H-C-C_ipso-C_ortho ca. 4° for 2,3-transphendimetrazine). Nonbonded interactions involving the 3-methyl and the 2-phenyl groups open up the H-C-C_ipso-C_ortho angle in a series of solid-state structures containing the epimeric (–)-(2R, 3S)-ephedrine moiety (e.g., ca. 45° for molecular mechanics calculated 2,3-cis-phendimetrazine model).     

Stabilization of aqueous suspensions of palygorskite by thermal vapour pressure shock explosion (TSE) treatment

A device was constructed in which a clay suspension is hermetically heated at 220°C for a few minutes. This thermal treatment is accompanied by a pressure increase in the cell. Once the valve is opened, there is a fast release of the pressure inside the cell and a sudden evolution of the interparticle water. This shock leads to a quasi explosion of the clay particle. This technique was named thermal vapour pressure shock explosion (TSE). The effect of TSE treatment on the properties of palygorskite suspensions was investigated. Palygorskite suspensions in water are rather unstable and particles smaller than 3 μm in size are not found before a TSE treatment. Stabilization of the suspension can be obtained by TSE treatments and/or by using a dispersing agent such as pyrophosphate, or both. As a result of TSE treatments smaller particles are obtained, the dispersiveness of the particles is improved and electrophoretic mobility is increased. Electron microscopy scans showed that the aggregates of needles which form the palygorskite fibres, disintegrate to separated thin needles as a result of the TSE treatment. Dedicated to Professor Lisa Heller-Kallai on the occasion of her 65^th birthday     

New route to ABCD-porphyrins via bilanes

A new strategy for preparing porphyrins that bear up to four different meso-substituents (ABCD-porphyrins) relies on two key reactions. One key reaction entails a directed synthesis of a 1-protected 19-acylbilane by acid-catalyzed condensation at high concentration (0.5 M) of a 1-acyldipyrromethane and a 9-protected dipyrromethane-1-carbinol (derived from a 9-protected 1-acyldipyrromethane). Three protecting groups (X) were examined, including thiocyanato, ethylthio, and bromo, of which bromo proved most effective. The bilanes were obtained in 72-80% yield, fully characterized, and examined by 15N NMR spectroscopy. The second key reaction entails a one-flask transformation of the 1-protected 19-acylbilane under basic, metal-templating conditions to give the corresponding metalloporphyrin. The reaction parameters investigated for cyclization of the bilane include solvent, metal salt, base, concentration, temperature, atmosphere, and time. The best conditions entailed the 1-bromo-19-acylbilane at 100 mM in toluene containing DBU (10 mol equiv) and MgBr2 (3 mol equiv) at 115 degrees C exposed to air for 2 h, which afforded the magnesium porphyrin in 65% yield. The magnesium porphyrin is readily demetalated to give the free base porphyrin. A stepwise procedure (which entailed treatment of the 1-(ethylthio)-19-acylbilane to oxidation, metal complexation, desulfurization, carbonyl reduction, and acid-catalyzed condensation) was developed but was much less efficient than the one-flask process. The new route to ABCD-porphyrins retains the desirable features of the existing "2 + 2" (dipyrromethane + dipyrromethane-1,9-dicarbinol) method, such as absence of scrambling, yet has significant advantages. The advantages include the absence of acid in the porphyrin-forming step, the use of a metal template for cyclization, the ability to carry out the reaction at high concentration, the lack of a quinone oxidant, avoidance of use of dichloromethane, and the increased yield of macrocycle formation to give the target ABCD-metalloporphyrin.     

Noroleanane Triterpenoids from the Aerial Parts of Lantana camara

Two novel triterpenoids, lantadienone ( 1 ) and camaradienone ( 2 ), were isolated from the aerial parts of Lantana camara, along with seven known compounds, lantadene A, lantadene B, β‐sitosterol 3‐(β‐D ‐glucopyranoside), camaric acid, lantanilic acid, lantanolic acid, and camangeloyl acid. Their structures were elucidated as (3β,22β)‐3,25‐epoxy‐3‐hydroxy‐22‐{[(2Z)‐2‐methyl‐1‐oxobut‐2‐enyl]oxy}‐28‐noroleana‐12,17‐dien‐11‐one ( 1 ) and (3β)‐3,25‐epoxy‐3‐hydroxy‐28‐noroleana‐12,17‐dien‐11‐one ( 2 ), respectively, by means of spectral studies. The triterpenoids 1 and 2 represent 28‐noroleananes oxidized at C(11) and C(22) or at C(11), reported for the first time.     

A UPLC-DAD-Based Bio-Screening Assay for the Evaluation of the Angiotensin Converting Enzyme Inhibitory Potential of Plant Extracts and Compounds: Pyrroquinazoline Alkaloids from Adhatoda vasica as a Case Study

Angiotensin converting enzyme (ACE) plays a crucial role in regulating blood pressure in the human body. Identification of potential ACE inhibitors from medicinal plants supported the idea of repurposing these medicinal plants against hypertension. A method based on ultra-performance liquid chromatography (UPLC) coupled with a diode array detector (DAD) was used for the rapid screening of plant extracts and purified compounds to determine their ACE inhibitory activity. Hippuryl-histidiyl-leucine (HHL) was used as a substrate, which is converted into hippuric acid (HA) by the action of ACE. A calibration curve of the substrate HHL was developed with the linear regression 0.999. The limits of detection and quantification of this method were found to be 0.134 and 0.4061 mM, respectively. Different parameters of ACE inhibitory assay were optimized, including concentration, incubation time and temperature. The ACE inhibition potential of Adhatoda vasica (methanolic-aqueous extract) and its isolated pyrroquinazoline alkaloids, vasicinol (1), vasicine (2) and vasicinone (3) was evaluated. Compounds 1–3 were characterized by various spectroscopic techniques. The IC₅₀ values of vasicinol (1), vasicine (2) and vasicinone (3) were found to be 6.45, 2.60 and 13.49 mM, respectively. Molecular docking studies of compounds 1–3 were also performed. Among these compounds, vasicinol (1) binds as effectively as captopril, a standard drug of ACE inhibition.     

Effect of arbitrary temperature degeneracy and ion magnetization on shear Alfven waves in electron-positron-ion plasmas

Linear properties of low-frequency electromagnetic shear Alfven waves (SAWs) are studied in quantum electron-positron-ion plasmas with effect of arbitrary temperature degeneracy for magnetized () and unmagnetized ( ) ions by using the quantum hydrodynamic model. Dispersion relations are derived for nearly degenerate () and nearly non-degenerate () plasmas. Bohm potential due to density correlation and temperature degeneracy due to Fermi–Dirac statistics of electron–positron, and their effects on the dispersion of SAWs are studied in detail both analytically and numerically. The relevance of the work regarding dense astrophysical plasmas is highlighted.     

Synthesis,Crystal Structure,Hirshfeld Surface Analysis,DFT, and DNA-Binding Studies of (E)-2-(3-Hydroxy-4-Methoxybenzylidene)Hydrazinecarbothioamide

Applied Biochemistry and Biotechnology - (E)-2-(3-Hydroxy-4-methoxybenzylidene)hydrazinecarbothioamide 3 was synthesized by reacting thiosemicarbazide with 2-hydorxy-3-methoxybenzaldehyde in dry...