Synthesis and antiviral activity of new indole-based heterocycles

New 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazine and 1,3-thiazole derivatives incorporating indole nucleus were prepared using 3-acetylindole as precursor and evaluated for their antiviral activity against herpes simplex type 1 (HSV-1).     

Towards a Unified Method for Exact Solutions of Evolution Equations. An Application to Reaction Diffusion Equations with Finite Memory Transport

We present a brief report on the different methods for finding exact solutions of nonlinear evolution equations. Explicit exact traveling wave solutions are the most amenable besides implicit and parametric ones. It is shown that most of methods that exist in the literature are equivalent to the “generalized mapping method” that unifies them. By using this method a class of formal exact solutions for reaction diffusion equations with finite memory transport is obtained. Attention is focused to the finite-memory-transport-Fisher and Nagumo equations.     

Piribedil-Selective Electrodes Based on Bi(III)-Iodide and Hg(II)-Iodide Complexes

 We describe new ion-selective electrodes for piribedil (PD) based on Bi(III)-iodide or Hg(II)-iodide piribedil ion associate complexes in a poly(vinyl chloride) (PVC) membrane with dibutylphthalate (DBP) and dioctylphthalate (DOP) as plasticizing solvent mediator. The electrodes (PD-[BiI₄]/DBP, PD-[BiI₄]/DOP, PD-[HgI₄]/DBP and PD-[HgI₄]/DOP) show nearly Nernstian response over the concentration range 2 × 10⁻⁵–10⁻² M of the drug. The working pH ranges were 3.1–6.0, 3.5–6.0, 3.0–6.0 and 3.5–6.4, and the isothermal coefficients of the cells were 0.00113, 0.00146, 0.00059 and 0.00120 V/°C for PD-[BiI₄]/DBP, PD-[BiI₄]/DOP, PD-[HgI₄]/DBP and PD-[HgI₄]/DOP, respectively. The selectivity coefficients for numerous compounds are given. The electrodes have been used for the direct determination of PD in pure form and in tablets or in biological fluids by the standard addition and potentiometric titration methods. Received May 30, 2001; accepted June 24, 2002     

Synthesis of Some New Thieno[2,3-b]pyridines,Pyrimidino[4′,5′:4,5]thieno[2,3-b]-pyridines,and 2,3-Dihydro-1,3,4-thiadiazoles

Thieno[2,3-b]pyridines were synthesized from 6-benzofuran-2-yl-4-phenyl-2-sulfanylpyridine-3-carbonitrile and each of chloro acetone, ethyl chloroacetate, ω -bromoacetophenone, and chloroacetonitrile. These compounds were conveniently converted into novel pyrido[4′,5′:4,5]thieno[3,2-d]pyrimidines. Also, 2,3-dihydro-1,3,4-thiadiazole was synthesized from hydrazonoyl halides and 2-benzofuran-2-yl-3-(phenylamino)-3-thioxopropanenitrile. The structures of the products have been elucidated by elemental analyses, spectral data studies, and alternative syntheses whenever possible. The newly synthesized compounds were tested towards microorganisms.     

Solvent Extraction of Eu(III) by Dihexyl-N,N-Diethylcarbamoyl Methyl Phosphonate (DHDECMP) from Perchlorate and Nitrate Media

Eu(III) extraction by DHDECMP has been studied from aqueous solution of perchlorate and nitrate. In case of perchlorate the distribution of Eu was found to be first power dependent on pH and third power dependent on extractant concentration. From nitrate it was found that D for Eu(III) is also first power with respect to pH but second power dependency on DHDECMP. The reaction mechanisms have been suggested and discussed in the light of the data obtained. The effect of adding some electron donor compounds decreases the extractability of DHDECMP for Eu(III) but does not change the nature of extracted species. The equilibrium constants of all the extracted species have been calculated and discussed. The extractant behaves as a chelate in low acidic media and extracted complex species is suggested to be Eu(NO₃)₂DHDECMP·DHDECMP from nitrate solutions.     

Fabrication of Membrane Sensitive Electrodes for the Validated Electrochemical Quantification of Anti-Osteoporotic Drug Residues in Pharmaceutical Industrial Wastewater

Accurate and precise application of ion-selective electrodes (ISEs) in the quantification of environmental pollutants is a strenuous task. In this work, the electrochemical response of alendronate sodium trihydrate (ALN) was evaluated by the fabrication of two sensitive and delicate membrane electrodes, viz. polyvinyl chloride (PVC) and glassy carbon (GC) electrodes. A linear response was obtained at concentrations from 1 × 10⁻⁵ to 1 × 10⁻² M for both electrodes. A Nernstian slope of 29 mV/decade over a pH range of 8–11 for the PVC and GC membrane electrodes was obtained. All assay settings were carefully adjusted to obtain the best electrochemical response. The proposed technique was effectively applied for the quantification of ALN in pure form and wastewater samples, acquired from manufacturing industries. The proposed electrodes were effectively used for the determination of ALN in real wastewater samples without any prior treatment. The current findings guarantee the applicability of the fabricated ISEs for the environmental monitoring of ALN.     

On $$\varvec{}$$-mixed-type soliton propagation in dispersive nonautonomous long waves with waveguides

In this paper N-soliton propagations for the Calogero–Bogoyavlenskii–Schiff (CBS) equation in an inhomogeneous media which describes the long nonautonomous waves are obtained. Here attention is focused to study the effect of the dispersion coefficient on the propagation solitons waves. It is found that N-bright-dark solitons are produced by periodic or coupled periodic and pulses waves. Solitons waves are propagated for two and three pulses with periodic oscillating. Further, the double-periodic and solitary waves are dispersive to broken-solitons waves for the graded-index with oscillating reflection components. These results are useful for the application for long-distance telecommunication and optical fiber.     

A method for finding the invariants and exact solutions of coupled non-linear differential equations with applications to dynamical systems

The polynomial invariants of (a set) non-linear differential equations are found by using a direct approach. The integrability of these invariants deserves the integrability of the given set of coupled differential equations. As applications, the Lorenz and Rikitake sets, among others, are studied. New invariants are obtained.     

On the Behavior of Solutions of a Class of Nonlinear Partial Differential Equations

The behavior of the steady-state (or the traveling wave) solutions for a class of nonlinear partial differential equations is studied. The nonlinearity in these equations is expressed by the presence of the convective term. It is shown that the steady-state (or the traveling wave) solution may explode at a finite value of the spatial (or the characteristic) variable. This holds whatever the order of the spatial derivative term in these equations. Furthermore, new special solutions of a set of equations in this class are also found.     

Antimicrobial activity of amino acid,imidazole, and sulfonamide derivatives of pyrazolo[3,4-d]pyrimidine

Derivatives of pyrazolo[3,4-d]pyrimidine with amino acid 3a–d , imidazole 4a–d , carbonyl 6–9 , pyrazole 10 , pyrazolone 11 , and sulfonamide 12–17 moieties were synthesized. Structure of the new compounds were established by their elemental analyses and spectral data. Some of the synthesized compounds were tested in vitro for their antimicrobial activity. Compounds 4b, 12 , and 16 were almost as potent as the standard antibiotic Chloramphenicol as positive control. Also, compounds 3b, 3c, 12 , and 16 were nearly as active as Terbinafine as positive control. © 2003 Wiley Periodicals, Inc. 15:57–62, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/.hc10212