2-Acetylpyridine- and 2-benzoylpyridine-derived thiosemicarbazones and their antimony(III) complexes exhibit high anti-trypanosomal activity

Complexes [Sb(2Ac4oClPh)Cl₂] (1), [Sb(2Ac4oFPh)Cl₂] (2), [Sb(2Ac4oNO₂Ph)Cl₂] (3), [Sb(2Bz4oClPh)Cl₂] (4), [Sb(2Bz4oFPh)Cl₂] (5) and [Sb(2Bz4oNO₂Ph)Cl₂] (6) were obtained with 2-acetylpyridine-N(4)-ortho-chlorophenyl thiosemicarbazone (H2Ac4oClPh) and its N(4)-ortho-fluor (H2Ac4oFPh) and N(4)-ortho-nitro (H2Ac4oNO₂Ph) analogues, and with the corresponding 2-benzoylpyridine-derived thiosemicarbazones (H2Bz4oClPh, H2Bz4oFPh, H2Bz4oNO₂Ph). The studied compounds are excellent inhibitors of Trypanosoma cruzi growth. H2Bz4oClPh and complexes (4) and (1) were the most trypanosomicidal.Upon coordination of H2Ac4oClPh to antimony(III) in 1, the therapeutic index (TI) goes from 10.58 to 14.35. However, the best values of TI were found for H2Bz4oClPh (TI = 1240) and H2Ac4oNO₂Ph (TI = 773). Structure-activity relationship (SAR) studies did not allow the establishment of correlations between the anti-trypanosomal activity and physico-chemical parameters, but correlations were found between the cytotoxicities and physico-chemical properties.     

Formulations for a problem of petroleum transportation

Oil tankers play a fundamental role in every offshore petroleum supply chain and due to its high price, it is essential to optimize its use. Since this optimization requires handling detailed operational aspects, complete optimization models are typically intractable. Thus, a usual approach is to solve a tactical level model prior to optimize the operational details. In this case, it is desirable that tactical models are as precise as possible to avoid too severe adjustments in the next optimization level. In this paper, we study tactical models for a crude oil transportation problem by tankers. We did our work on the top of a previous paper found in the literature. The previous model considers inventory capacities and discrete lot sizes to be transported, aiming to meet given demands over a finite time horizon. We compare several formulations for this model using 50 instances from the literature and proposing 25 new harder ones. A column generation-based heuristic is also proposed to find good feasible solutions with less computational burden than the heuristics of the commercial solver used.     

Synthesis of a Novel Fused Thiophene‐thieno[3,2‐b]thiophene‐thiophene Donor Monomer and Co‐polymer for Use in OPV and OFETs

The synthesis of a novel fused hexacyclic electron rich monomer incorporating thieno[3,2‐b]thiophene is reported and characterized by single crystal X‐ray diffraction. Suzuki co‐polymerization with benzothiadiazole (BT) afforded a novel low band‐gap polymer P4TBT with high molecular weights and good solution processability. Bulk heterojunction solar cell devices using the P4TBT and [70]PCBM gave power conversion efficiencies of 2.5%. Top‐gate, bottom‐contact field effect transistors (FETs) using P4TBT displayed high hole mobilities of 0.07 cm² · Vs⁻¹ demonstrating the suitability of the novel monomer and polymer for use in high performing organic electronic devices.

     

Complete Chiral Resolution Using Additive‐Induced Crystal Size Bifurcation During Grinding

Grinding them down: By using a tailor‐made additive, even in the absence of racemization in solution, abrasive grinding can yield an enantiopure solid state. This novel chiral resolution technique is based on an asymmetric bifurcation in the crystal size distribution as a result of stereoselective hampered crystal growth. R=o‐tolyl.

     

Exploring laccase-like multicopper oxidase genes from the ascomycete <Emphasis Type="Italic">Trichoderma reesei</Emphasis>: a functional,phylogenetic and evolutionary study

Background  

The diversity and function of ligninolytic genes in soil-inhabiting ascomycetes has not yet been elucidated, despite their possible role in plant litter decay processes. Among ascomycetes, Trichoderma reesei is a model organism of cellulose and hemicellulose degradation, used for its unique secretion ability especially for cellulase production. T. reesei has only been reported as a cellulolytic and hemicellulolytic organism although genome annotation revealed 6 laccase-like multicopper oxidase (LMCO) genes. The purpose of this work was i) to validate the function of a candidate LMCO gene from T. reesei, and ii) to reconstruct LMCO phylogeny and perform evolutionary analysis testing for positive selection.     

Exploiting automatic on-line renewable molecularly imprinted solid-phase extraction in lab-on-valve format as front end to liquid chromatography: application to the determination of riboflavin in foodstuffs

In the present work, it is proposed, for the first time, an on-line automatic renewable molecularly imprinted solid-phase extraction (MISPE) protocol for sample preparation prior to liquid chromatographic analysis. The automatic microscale procedure was based on the bead injection (BI) concept under the lab-on-valve (LOV) format, using a multisyringe burette as propulsion unit for handling solutions and suspensions. A high precision on handling the suspensions containing irregularly shaped molecularly imprinted polymer (MIP) particles was attained, enabling the use of commercial MIP as renewable sorbent. The features of the proposed BI-LOV manifold also allowed a strict control of the different steps within the extraction protocol, which are essential for promoting selective interactions in the cavities of the MIP. By using this on-line method, it was possible to extract and quantify riboflavin from different foodstuff samples in the range between 0.450 and 5.00 mg L⁻¹ after processing 1,000 μL of sample (infant milk, pig liver extract, and energy drink) without any prior treatment. For milk samples, LOD and LOQ values were 0.05 and 0.17 mg L⁻¹, respectively. The method was successfully applied to the analysis of two certified reference materials (NIST 1846 and BCR 487) with high precision (RSD < 5.5%). Considering the downscale and simplification of the sample preparation protocol and the simultaneous performance of extraction and chromatographic assays, a cost-effective and enhanced throughput (six determinations per hour) methodology for determination of riboflavin in foodstuff samples is deployed here.     

Enantiodivergent synthesis of P-chirogenic phosphines

Several approaches for the enantiodivergent synthesis of P-chirogenic mono- and diphosphines are described, using ephedrine methodology and phosphine borane chemistry. Firstly, both enantiomers of a tertiary phosphine can be obtained starting from the same oxazaphospholidine borane complex, prepared from (+)-ephedrine, when changing the order of addition of the organolithium reagents during the synthetic pathway. The second approach is based on the chlorophosphine boranes, which react with an organolithium reagent, to afford the corresponding phosphines with inversion of configuration. In the case where the chlorophosphine borane reacts with the t-butyl lithium reagent, a metal-halogen exchange occurs to afford the corresponding phosphide borane with retention of the configuration. The reaction of the phosphide borane with an alkyl halide leads to the same phosphine, but with the opposite configuration. Another approach depends on the diastereoselective preparation of the starting oxazaphospholidine borane complex from (?)-ephedrine, which leads according the case, to either one or the other enantiomer of a phosphine. Finally, the synthesis of (R,R)- and (S,S)-1,2-bis(methylphenylphosphino)ethane is also demonstrated using both enantiomers of the P-chirogenic diphosphinite diborane, which simultaneously allows the introduction of alkyl- or aryl substituents on the phosphorus atoms. In summary, these approaches show the great efficiency of the “ephedrine methodology” for the enantiodivergent synthesis of P-chirogenic mono- and diphosphines, and bearing alkyl or aryl substituents.     

Quantitative full-colour transmitted light microscopy and dyes for concentration mapping and measurement of diffusion coefficients in microfluidic architectures

A simple and versatile methodology has been developed for the simultaneous measurement of multiple concentration profiles of colourants in transparent microfluidic systems, using a conventional transmitted light microscope, a digital colour (RGB) camera and numerical image processing combined with multicomponent analysis. Rigorous application of the Beer-Lambert law would require monochromatic probe conditions, but in spite of the broad spectral bandwidths of the three colour channels of the camera, a linear relation between the measured optical density and dye concentration is established under certain conditions. An optimised collection of dye solutions for the quantitative optical microscopic characterisation of microfluidic devices is proposed. Using the methodology for optical concentration measurement we then implement and validate a simplified and robust method for the microfluidic measurement of diffusion coefficients using an H-filter architecture. It consists of measuring the ratio of the concentrations of the two output channels of the H-filter. It enables facile determination of the diffusion coefficient, even for non-fluorescent molecules and nanoparticles, and is compatible with non-optical detection of the analyte.