Diverse reactivity of 2-formylphenylboronic acid with secondary amines: synthesis of 3-amino-substituted benzoxaboroles

In the reaction of 2-formylphenylboronic acid with secondary amines different products are formed depending on the structure of the amines. For aliphatic amines the reaction proceeds with the formation of 3-amino-substituted benzoxaboroles or with the formation of complexed boroxins. A crystal structure of the benzoxaborole with a thiomorpholinyl substituent was determined.     

New efficient ruthenium metathesis catalyst containing chromenyl ligand

A synthesis of new Hoveyda-Grubbs-type catalyst with chromenyl ligand was described herein. The new catalyst was tested in model RCM and CM reactions. The catalyst proved to be quite efficient. It showed activity comparable or superior to that of commercially available Grubbs second-generation complexes.     

The reaction of optically active α-aminocarboxylic acid hydrazides with triethyl orthoesters

New derivatives of 2-(1-amino-1-phenylmethyl)-1,3,4-oxadiazole and 1,2,4-triazin-6-one were synthesised in the reactions of optically active α-aminocarboxylic acid hydrazides and triethyl orthoesters in xylene. The electronic and steric effects of substituents at the α position influencing the formation of five- or six-membered products are discussed.     

Thermo-chemical properties of biomass from Posidonia oceanica

Posidonia oceanica (PO) is a marine plant endemic to the Mediterranean basin, forming extensive grasslands. Onshore residues represent a major environmental, economic, social and hygienic problem in all coastal zones of the Mediterranean basin due to the great disturbance they cause to bathers and beachfront populations. This work sought to evaluate the thermo-chemical properties of PO in pyrolysis and thermo-oxidative degradation processes. The investigations were carried out using a thermogravimetric analyser (TGA) coupled to a quadrupole mass spectrometer (MS) and an infrared spectrometer (FTIR). In addition, proximate, ultimate, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and biodegradability analyses were carried out on PO. The biodegradability analysis confirmed that residues of PO were a biodegradable material. Accordingly, the application of PO as a feedstock for combustion/co-combustion or biorefining is recommended.     

On existence of integrable solutions of a functional integral equation under Carathéodory conditions

We study the solvability of a functional integral equation in the space of Lebesgue integrable functions on an unbounded interval. Using the conjunction of the technique of measures of weak noncompactness with the classical Schauder fixed point principle we show that the equation in question is solvable in the mentioned function space. Our existence result is obtained under the assumption that functions involved in the investigated functional integral equation satisfy Carathéodory conditions. Moreover, that result generalizes several ones obtained earlier in many research papers and monographs.     

A Novel Synthesis of 1-Aminoalkanephosphonic Acid Derivatives from 1-(N-Acylamino)- alkyltriphenylphosphonium Salts

Efficient and convenient procedures for the α-amidoalkylation of trialkylphosphites with 1-(N-acylamino)alkyltriphenylphosphonium salts followed by a Michaelis–Arbuzov-type reaction to afford 1-(N-acylamino)alkanephosphonic acid esters have been developed. High yields and simple isolation and purification protocols are the main advantages of this method.     

Discrete leader‐following consensus

In this paper, a leader‐following consensus of discrete‐time multi‐agent systems with nonlinear intrinsic dynamics is investigated. We propose and prove conditions ensuring a leader‐following consensus. Numerical examples are given to illustrate our results.     

Densities and excess molar volumes for mixtures of methanol with other alcohols at temperatures (288.15–313.15 K)

Densities have been measured for the binary mixtures of methanol with ethanol, isomers of propanol and butanol over the entire composition range at 288.15, 293.15, 298.15, 303.15, 308.15, 313.15 K. The density data have been used to calculate the molar volumes, thermal expansion coefficients and their excess values. The excess parameters have been fitted to the Redlich–Kister polynomial equation. The values of the molar volumes, excess molar volumes, thermal expansion coefficients and excess thermal expansion coefficients have been analyzed as a function of the mole fraction and the carbon chain length.     

Determination of tin in marine sediments by slurry sampling atomic absorption spectrometry with electrothermal atomization using a permanent modifier

A molecularly imprinted polymer (MIP) was synthesized by the precipitation polymerization method using triazophos (TAP) as the template. The MIP can selectively absorb TAP from sample solutions. The absorbed TAP strongly enhances the chemiluminescence (CL) of luminol-H₂O₂. This was applied to design a method for the on-line enrichment and detection of TAP. The change in CL intensity is linearly proportional to the concentration of TAP in the range from 1.0 μM to ~4.0 nM, and the detection limit is 2.5 nM (at an S/N of 3σ). This is about one order of magnitude lower than that of the conventional CL assay. The method was successfully applied to the determination of TAP in vegetable samples.