Facile access to γ-aminothiols from 1,3-thiazines via a microwave-assisted three-component reaction

A new efficient and general synthetic methodology to access γ-aminothiols was investigated and developed. 1,3-Thiazines were used as convenient precursors and were prepared by a fast microwave-assisted three-component reaction (3CR) of thioamides, aldehydes, and alkenes. The transformation of thiazines into aminothiols was achieved via a thiazinium salt hydrolysis, in three very facile steps.     

New eco-friendly animal bone meal catalysts for preparation of chalcones and aza-michael adducts

ABSTRACT: Two efficient reactions were successfully carried out using Animal Bone Meal (ABM) and potassium fluoride or sodium nitrate doped ABMs as new heterogeneous catalysts under very mild conditions. After preparation and characterization of the catalysts, we first report their use in a simple and convenient synthesis of various chalcones by Claisen-Schmidt condensation and then in an aza-Michael addition involving several synthesized chalcones with aromatic amines. All the reactions were carried out at room temperature in methanol; the chalcone synthesis was also achieved in water environment under microwave irradiation. Doping ABM enhances the rate and yield at each reaction. Catalytic activities are discussed and the ability to re-use the ABM is demonstrated. RESULTS: For Claisen-Schmidt the use of ABM alone, yields never exceeded 17%. In each entry, KF/ABM and NaNO3/ABM (79-97%) gave higher yields than using ABM alone under thermic condition. Also the reaction proceeded under microwave irradiation in good yields (72-94% for KF/ABM and 81-97% for NaNO3/ABM) and high purity. For aza-Michael addition the use of ABM doped with KF or NaNO3 increased the catalytic activity remarkably. The very high yields could be noted (84-95% for KF/ABM and 81-94% for NaNO3/ABM). CONCLUSION: The present method is an efficient and selective procedure for the synthesis of chalcones anaaza-Michael adducts. The ABM and doped ABMs are a new, inexpensive and attractive solid supports which can contribute to the development of catalytic processes and reduced environmental problems.     

Coordination Polymers. 9. Chelate Polymers Derived from Bisphenolic Complexes and Propylenediamine

Chelate polymers derived from bis(2,4-dihydroxybenzaldehyde)propyl-enediimine M and bis(2,4-dihydroxyacetophenone)propylenediimine M (M = Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺) with aromatic acid chlorides were prepared by interfacial polycondensation. Also, chelate polysiloxanes were obtained from the same monomers and α,ω-dichloropolydimethyl-siloxane. The spectral, thermal, magnetic, and electrical properties of the polychelates were studied.     

Investigation of thermal stability, spectral, magnetic, and antimicrobial behavior for new complexes of Ni(II), Cu(II), and Zn(II) with a bismacrocyclic ligand

Novel complexes of type M₂LCl₄·nH₂O (M: Ni, n = 4; M: Cu, n = 2.5 and M: Zn, n = 1.5; L: ligand resulted from 1,3-phenylenediamine, 3,6-diazaoctane-1,8-diamine, and formaldehyde one-pot condensation) were synthesized and characterized. The ligand was also isolated and characterized. The complexes features have been assigned from microanalytical, electrospray ionization tandem mass spectrometry, IR, UV–vis, ¹H NMR, and EPR spectra as well as magnetic data at room temperature. Simultaneous thermogravimetric/dynamic scanning calorimetry/evolved gas analysis measurements were performed to evidence the nature of the gaseous products formed in each step. Processes as water elimination, fragmentation, and oxidative degradation of the organic ligand as well as chloride elimination were observed during the thermal decomposition. The final product of decomposition was metal(II) oxide except for copper complex where CuCl remained also in the oxide network. The complexes exhibited an improved antibacterial activity in comparison with the ligand concerning both planktonic as well as biofilm-embedded cells.     

Affinity capillary electrophoresis to evaluate the complex formation between poliovirus and nanobodies

It was demonstrated that nanobodies with an in vitro neutralizing activity against poliovirus type 1 interact with native virions. Here, the use of capillary electrophoresis was investigated as an alternative technique for the evaluation of the formation of nanobody–poliovirus complexes, and therefore predicting the in vitro neutralizing activity of the nanobodies. The macromolecules are preincubated offline in a specific nanobody‐to‐virus ratio and analyzed by capillary electrophoresis with UV detection. At low nanobody‐to‐virus ratios, a clear shift in migration time of the viral peak was observed. A broad peak was obtained, indicating the presence of a heterogeneous population of nanobody–virion complexes, caused by the binding of different numbers of nanobodies to the virus particle. At elevated nanobody‐to‐virus ratios, a cluster of peaks appeared, showing an additional increase in migration times. It was shown that, at these high molar excesses, aggregates were formed. The developed capillary electrophoresis method can be used as a rapid, qualitative screening for the affinity between poliovirus and nanobodies, based on a clearly visible and measurable shift in migration time. The advantages of this technique include that there is no need for antigen immobilization as in enzyme‐linked immunosorbent assays or surface plasmon resonance for the use of radiolabeled virus or for the performance of labor‐ and time‐intensive plaque‐forming neutralization assays.     

Synthesis and antibacterial properties of new phenothiazinyl- and phenyl-nitrones

The synthesis of new phenothiazinyl- and phenyl-nitrones under classical versus microwave heating conditions is described. Better yields were obtained under microwave irradiation in the condensation reactions of phenothiazyl-carbaldehyde with hydroxylamine derivatives. The structures of the new phenothiazinyl-nitrones were assigned on the basis of MS, FT–IR and NMR spectra. The new nitrones and some known phenyl-nitrones were screened for their antibacterial and antifungal activity against several Candida species, Gram negative bacteria, such as E. coli, Citrobacter spp, Morganella spp, Pseudomonas aeruginosa, Klebsiella pneumoniae (± ESBL), Proteus spp, Acinetobacter spp and the Gram positive bacterium Staphylococcus aureus, with moderate results.     

Hydrogen bonding-based 3D supramolecular architecture of [Cu(CHA)2][TCM]·11H2O

Reaction of Na₄TCM (1) (H₄TCM = tetra[4-(carboxyphenyl)oxamethyl]methane) with [Cu(CHA)](ClO₄)₂ (2)(CHA = 1,3,6,8,11,14-hexaaz atricyclo[12.2.1.1.^8,11] octadecane) in a DMF-water mixture yields [Cu(CHA)]₂[TCM] (3). Structural analysis of [Cu(CHA)]₂[TCM]·11H₂O (3·11H₂O) by single crystal X-ray diffraction reveals strong copper-oxygen bonds between two complex cations and the tetraanion leading to a 3D coordination network (zwitterionic structure), consolidated through additional NH...O=C hydrogen bonding within the cation/anion association. The resulting coordination geometry around a copper atom is a distorted square pyramidal with an oxygen atom of the anionic ligand in the apical position. A 3D supramolecular network is developed in the crystal based only on NH...OC hydrogen bonds between the macrocyclic metallic tecton and the carboxylate groups of neighboring 3D coordinated (zwitterionic) moieties. The pseudotetrahedral TCM^4? tetraanionic ligand induces a diamondoid architecture formed of large distorted adamantanoid cages.      

Synthesis,characterization and controlled toxicity of a novel hybrid material based on cisplatin and docetaxel

This paper is focused on the synthesis and characterization of a novel hybrid material based on cisplatin and docetaxel-loaded functionalized simultanously carbon nanotubes able to be used in cancer therapy as drug delivery system with controlled toxicity. This material was physico-chemically investigated by determining the structure, as evidenced by Fourier transform infrared (FTIR) spectroscopy, transmission electronmicroscopy (TEM) and its stability was studied with the aid of thermogravimetric analysis (TGA). The amount of platinum ions released into the solution of simulated body fluid (SBF) was highlighted by coupled plasma mass spectrometry (ICP-MS). Toxicology experiments were performed with MDA-MB 231 breast cancer epithelial cells. The performance of the new drug delivery hybrid material was compared with functionalised carbon nanotubes with therapeutic agents functionalized with a single therapeutic agent.      

Electrochemical Peptide-Based Sensors for Foodborne Pathogens Detection

Food safety and quality control pose serious issues to food industry and public health domains, in general, with direct effects on consumers. Any physical, chemical, or biological unexpected or unidentified food constituent may exhibit harmful effects on people and animals from mild to severe reactions. According to the World Health Organization (WHO), unsafe foodstuffs are especially dangerous for infants, young children, elderly, and chronic patients. It is imperative to continuously develop new technologies to detect foodborne pathogens and contaminants in order to aid the strengthening of healthcare and economic systems. In recent years, peptide-based sensors gained much attention in the field of food research as an alternative to immuno-, apta-, or DNA-based sensors. This review presents an overview of the electrochemical biosensors using peptides as molecular bio-recognition elements published mainly in the last decade, highlighting their possible application for rapid, non-destructive, and in situ analysis of food samples. Comparison with peptide-based optical and piezoelectrical sensors in terms of analytical performance is presented. Methods of foodstuffs pretreatment are also discussed.