Heterocyclic Synthesis with 4-Benzoyl-1-cyanoacetylthiosemicarbazide: Selective Synthesis of Some Thiazole, Triazole, Thiadiazine, Pyrrylthiazole, and Pyrazolo[1,5-a]triazine Derivatives

4-Benzoyl-1-cyanoacetylthiosemicarbazide undergoes coupling reaction with aromatic diazonium chloride to afford (arylhydrazono)thiosemicarbazide, which was reacted with phenacyl bromide regioselectivity to afford the thiazoline. The (arylhydrazono)thiosemicarbazide could be transformed into the pyrazolo[1,5-a]triazine. Heterocyclization of 4-benzoyl-1-cyanoacetylthiosemicarbazide with α-haloketones (bromoacetone and phenacyl bromide), ethyl iodide, and ethyl bromoacetate furnished the pyrrylthiazoles, 1,2,4- triazole, and 1,3,4-thiadiazine. The latter was coupled with aromatic diazonium chloride to give the bis(arylhydrazono)‐thiadiazine. The mechanism for the formation of the title compounds was suggested and discussed.     

Heterocyclic Synthesis with 4-Benzoyl-1-cyanoacetylthiosemicarbazide: Selective Synthesis of Some Thiazole,Triazole, Thiadiazine,Pyrrylthiazole, and Pyrazolo[1,5-<Emphasis Type="Italic">a</Emphasis>]triazine Derivatives

Summary. 4-Benzoyl-1-cyanoacetylthiosemicarbazide undergoes coupling reaction with aromatic diazonium chloride to afford (arylhydrazono)thiosemicarbazide, which was reacted with phenacyl bromide regioselectivity to afford the thiazoline. The (arylhydrazono)thiosemicarbazide could be transformed into the pyrazolo[1,5-a]triazine. Heterocyclization of 4-benzoyl-1-cyanoacetylthiosemicarbazide with α-haloketones (bromoacetone and phenacyl bromide), ethyl iodide, and ethyl bromoacetate furnished the pyrrylthiazoles, 1,2,4- triazole, and 1,3,4-thiadiazine. The latter was coupled with aromatic diazonium chloride to give the bis(arylhydrazono)‐thiadiazine. The mechanism for the formation of the title compounds was suggested and discussed.     

Stereodivergent Zweifel Olefination and its Mechanistic Dichotomy

Stereoselective Zweifel olefination using boronate complexes carrying two different reactive π-systems was achieved to synthesize vinyl heteroarenes and conjugated 1,3-dienes in good yield and up to 100 % stereoselectivity, which remains unexplored until now. Most importantly, we report the unprecedented formation of E vs. Z-vinyl heteroarenes for different heteroarenes under identical conditions. Density functional theory (DFT) investigations unveil the mechanistic dichotomy between olefin and heteroarene activation followed by 1,2-migration, leading to E or Z-vinyl heteroarenes respectively. We also report a previously unknown reversal of stereoselectivity by using 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as an electrophile. The Zweifel olefination using a boronate complex that carries two different olefins was previously unexplored due to significant challenges associated with the site-selective activation of olefins. We have solved this problem and reported the site-selective activation of olefins for the stereoselective synthesis of 1,3-dienes.     

Electrochemical Nickel-Catalyzed Selective Inter- and Intramolecular Arylations of Cysteine-Containing Peptides**

Here we report a simple electrochemical route towards the synthesis of S-arylated peptides by a site selective coupling of peptides with aryl halides under base free conditions. This approach demonstrates the power of electrochemistry to access both highly complex peptide conjugates and cyclic peptides.     

A Novel Fluorimetric Bulk Optode Membrane Based on NOS Tridentate Schiff Base for Selective Optical Sensing of Al<Superscript>3+</Superscript> Ions

A novel fluorimetric optode has been developed for the highly selective and sensitive for the determination of ultra trace amounts of Al³⁺ ions. The proposed fluorescent optode is based on the incorporation of a simple and effective fluorescent sensor tridentate NOS Schiff base N-(2-hydroxynaphthylidene)-2-aminothiophenol (H₂L) in a plasticized PVC containing KTpClPB as a lipophilic anionic additive. H₂L was synthesized by a facile one-step Schiff base reaction. The plasticized PVC-membrane displays a calibration response for Al³⁺ ions over a wide concentration range from 1.0 × 10^?9 to 4.4 × 10^?3 mol/L. The fluorescence signal of the optode membrane can be easily recovered by immersion in 0.01 M EDTA. In addition to high stability and reproducibility, the sensor shows a unique selectivity towards Al³⁺ ion with respect to common co-existing cations, particularly Ga³⁺and In³⁺. The proposed optode was applied successfully for determination of Al³⁺ in some real samples, including bottled drinking waters, bottled mineral waters and soft drinks.     

Nonsmooth Lur’e Dynamical Systems in Hilbert Spaces

In this paper, we study the well-posedness and stability analysis of set-valued Lur’e dynamical systems in infinite-dimensional Hilbert spaces. The existence and uniqueness results are established under the so-called passivity condition. Our approach uses a regularization procedure for the term involving the maximal monotone operator. The Lyapunov stability as well as the invariance properties are considered in detail. In addition, we give some sufficient conditions ensuring the robust stability of the system in finite-dimensional spaces. The theoretical developments are illustrated by means of two examples dealing with nonregular electrical circuits and an other one in partial differential equations. Our methodology is based on tools from set-valued and variational analysis.     

Multielement analytical procedure coupling INAA, ICP-MS and ICP-AES: Application to the determination of major and trace elements in sediment samples of the Bouregreg river (Morocco)

Instrumental neutron activation analysis (INAA), inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) were used for the determination of major and trace elements in sediment samples of the Bouregreg river (Morocco). The reliability of the results was checked, by using IAEA Soil-7 certified reference material. Results obtained by the three techniques were compared to control digestions efficiencies. A general good agreement was found between INAA and both ICP-MS and ICP-AES after alkaline fusion (ICPf). The ICP-MS technique used after acid attack (ICPa) was satisfactory for a few elements. A principal component analysis (PCA) has been used for analyzing the variability of concentrations, and defining the most influential sites with respect to the general variation trends. Three groups of elements could be distinguished. For these groups a normalization of concentrations to the central element concentration (that means Mn, Si or Al) is proposed.     

The near-infrared (1.30-1.70 microm) absorption spectrum of methane down to 77 K

The high resolution absorption spectrum of methane has been recorded at liquid nitrogen temperature by direct absorption spectroscopy between 1.30 and 1.70 microm (5850-7700 cm(-1)) using a newly developed cryogenic cell and a series of DFB diode lasers. The investigated spectral range includes part of the tetradecad and the full icosad regions for which only very partial theoretical analysis are available. The analysis of the low temperature spectrum will benefit from the reduction of the rotational congestion and from the narrowing by a factor of 2 of the Doppler linewidth allowing the resolution of a number of multiplets. Moreover, the energy value and rotational assignment of the angular momentum J of the lower state of a given transition can be obtained from the temperature variation of its line intensity. This procedure is illustrated in selected spectral regions by a continuous monitoring of the spectrum during the cell cool-down to 77 K, the temperature value being calculated at each instant from the measured Doppler linewidth. A short movie showing the considerable change of a spectrum during cool-down is attached as Supplementary Material. The method applied to a 30 cm(-1) section of the tetradecad spectrum around 6110 cm(-1) has allowed an unambiguous determination of the J values of part of the observed transitions.     

Sensitivity analysis of maximally monotone inclusions via the proto-differentiability of the resolvent operator

This paper is devoted to the study of sensitivity to perturbation of parametrized variational inclusions involving maximally monotone operators in a Hilbert space. The perturbation of all the data involved in the problem is taken into account. Using the concept of proto-differentiability of a multifunction and the notion of semi-differentiability of a single-valued map, we establish the differentiability of the solution of a parametrized monotone inclusion. We also give an exact formula of the proto-derivative of the resolvent operator associated to the maximally monotone parameterized variational inclusion. This shows that the derivative of the solution of the parametrized variational inclusion obeys the same pattern by being itself a solution of a variational inclusion involving the semi-derivative and the proto-derivative of the associated maps. An application to the study of the sensitivity analysis of a parametrized primal-dual composite monotone inclusion is given. Under some sufficient conditions on the data, it is shown that the primal and the dual solutions are differentiable and their derivatives belong to the derivative of the associated Kuhn–Tucker set.