Ionic liquid effects on the reaction of β-enaminones and tert-butylhydrazine and applications for the synthesis of pyrazoles

In order to evaluate the effect of a series of 10 different ionic liquids ([BMIM][BF₄], [BMIM][Br], [OMIM][BF₄], [BMIM][PF₆], [DBMIM][Br], [DBMIM][BF₄], [BMIM][OH], [BMIM][SCN], [HMIM][HSO₄] and [HMIM][CF₃CO₂]) the cyclocondensation reaction between 4-dimethylamino-1-phenyl-3-alken-2-ones (RC(O)CHCHNMe₂, where R = Ph, 4-Me-Ph, 4-F-Ph, 4-Cl-Ph, 4-Br-Ph, 4-NO₂-Ph, thien-2-yl, fur-2-yl, pyrrol-2-yl, pyrid-2-yl, hexyl, dimethoxymethyl) and tert-butylhydrazine was performed. The effects of each ionic liquid are discussed and the best yields for the cyclocondensation reaction studied were obtained using [BMIM][BF₄].     

Hybridized 4-Trifluoromethyl-(1,2,3-triazol-1-yl)quinoline System: Synthesis,Photophysics, Selective DNA/HSA Bio-interactions and Molecular Docking

The synthesis, structural analysis, and evaluation of the photophysical properties of twelve novel 2-aryl(heteroaryl)-6-(4-alkyl(aryl)-1H-1,2,3-triazol-1-yl)-4-(trifluoromethyl)quinolines ( 6-8 ), where aryl(heteroaryl)=Ph, 4-Me-C₆H₄, 4-F-C₆H₄ and 2- furyl; 4-alkyl(aryl)=−CH₂OH, −(CH₂)₅CH₃ and Ph, are reported. Hybrid scaffolds 6 – 8 were synthesized at 77–95 % yields by regioselective copper-catalysed azide-alkyne cycloaddition (CuAAC) reaction of unpublished 6-azido-4-(trifluoromethyl)quinolines ( 2 ) with selected terminal alkynes ( 3 – 5 ). Azido intermediates 2 were obtained from the reaction of 6-amino-4-(trifluoromethyl)quinolines ( 1 ) and sodium azide at good yields (78–87 %). Compounds 6 – 8 were structurally fully characterized by ¹H−, ¹³C− and ¹⁹F− and ¹H−¹³C 2D-NMR (HSQC, HMBC) spectroscopy, X-ray diffraction (SC-XRD) and HRMS analysis. Moreover, the photophysical properties, DNA- and HSA-binding experiments (bio-interactions), and molecular docking studies for compounds 6 – 8 were performed. These are discussed and compared with similar compounds from recent research.     

Dexamethasone pharmacokinetics in clinically normal dogs during low- and high-dose dexamethasone suppression testing

Dexamethasone pharmacokinetics was studied in 10 healthy dogs receiving high-dose administration of dexamethasone (dosage, 0.1 mg/kg of body weight, IV), alone or combined with ACTH (dosage, 0.5 U/kg, IV), or low-dose administration of dexamethasone (dosage, 0.01 mg/kg, IV) in an incomplete cross-over design. Serum samples were obtained at 0, 5, 10, 15, 20, 30, 45, 60, 90, 120, 180, 240, 360, 480, 720, 1,080, 1,440, 1,920, 2,400, and 2,880 minutes after dexamethasone administration; dexamethasone was measured by radioimmunoassay validated for use in dogs. Dexamethasone pharmacokinetics was adequately described by a two-compartment first-order open model. Comparison of pharmacokinetics for the low- and high-dose protocols revealed dose dependence; area under the curve, mean residence time, clearance, and volume of distribution increased significantly when dexamethasone dosage increased. The elimination rate constant was significantly (P < 0.05) less, and the elimination half-life significantly greater for the high-dose protocols; however, the distribution rate constant and distribution half-life were not significantly different when high-dose protocols were compared with the low-dose protocol. Dose-dependent increases in volume of distribution and clearance may be related to saturation of protein-binding sites. Concurrent administration of ACTH did not affect dexamethasone disposition.     

Bromo-Substituted Diazenyl-pyrazolo[1,5-a]pyrimidin-2-amines: Sonogashira Cross-Coupling Reaction,Photophysical Properties,Bio-interaction and HSA Light-Up Sensor

A convenient synthesis of a broad series of thirteen examples of alkyne-spacer derivatives 2 from the well-known Sonogashira cross-coupling reaction on diazenyl-pyrazolo[1,5-a]pyrimidin-2-amine compounds 1 is reported. The reactivity of heterocycles 1 due the presence of selected electron-donor (EDG) and electron-withdrawing (EWG) groups attached to different alkynes was evaluated. Also, the reactional versatility due the position variation of the bromo atom at the scaffolds 1 was also investigated. In general, derivatives presented strong absorption bands at the 250–500 nm optical window and UV to cyan emission properties. Also, the redox analysis was recorded by electrochemical cyclic voltammetry technique. For HSA biomacromolecule assays, spectroscopic studies by UV-Vis, steady-state and time-resolved emission fluorescence, and molecular docking calculations evidenced the ability of each compound to establish interactions with human serum albumin (HSA). Finally, the behavior presented for this new class of heterocycles makes them a promising tool as optical sensors for albumins.     

Adaptation of the plasma process with automatic wire feeding for recovery of surfaces by automated welding

Damaged surfaces are normally recovered by means of processes of welding; they normally have complex geometries and are located in positions that are unfavourable for welding. Automated welding is the natural alternative as it presents advantages when compared with the manual process, such as reductions in the time and total cost of the recovery, better control of the geometry of the recovered surface, better uniformity and welding quality. Automated welding using the plasma process with automatic wire feed, although it provides excellent geometric and surface quality for the deposits, a significant reduction in welding defects and an absence of spatter, is very sensitive to variations in the torch–piece distance and to changes of welding position. In this context, the present work deals with an analysis of the changes made to the position of the wire in relation to the electric arc and the weld bead, to the orientation of the torch in relation to the surface to be welded and to the welding parameters that make the plasma welding process more robust due to geometric alterations to the surface to be welded. The practical results achieved in the most critical situations, from the point of view of welding damaged surfaces, are presented with the objective of validating the changes proposed for the fed plasma process.     

Synergic Effects of Ionic Liquid and Microwave Irradiation in Promoting Trifluoromethylpyrazole Synthesis

Abstract  

The synthesis of 5-trifluoromethyl-1-phenyl-1H-pyrazoles from the reactions of 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones [CF₃C(O)CH=C(R¹)OR, where R = Me, Et; R¹ = H, Me, Bu, i-Bu, Ph, 4-MeC₆H₄, 4-FC₆H₄, 4-ClC₆H₄, 4-BrC₆H_4, 4-IC₆H_4, fur-2-yl] with phenyl hydrazine in the presence of ionic liquid [BMIM][BF₄] is reported. Synergic effects of ionic liquid and microwave irradiation in promoting pyrazole synthesis have been shown for the first time.     

Differences and consistency between same-sex and other-sex peer relationships during early adolescence.

Studied, with 3 samples, children's and early adolescents' preferences for same-sex peers and the consistency of individual differences in reputation and popularity across the same- and other-sex domains. Findings indicate that individual differences in the same-sex preference (1) derived from children's liking of other-sex peers, (2) were consistent over relatively long intervals, and (3) were related to children's preferences for activities requiring gross motor skills. Same- and other-sex popularity had the same reputational correlates, except that acceptance among other-sex peers was more closely tied to prominence in the peer group. These findings are discussed according to children's and early adolescents' perceptions of and experiences with same- and other-sex peers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ionic Liquids Promoted the C-Acylation of Acetals in Solvent-free Conditions

The synthesis of a series of fourteen 4-alkoxy-1,1,1-trihalo-3-alken-2-ones (2,3) [CX₃COC(R²)=C(R¹)OMe, where X = Cl, F; R¹/R² = Me/H, Bu/H, i-Bu/H, Ph/H, Thien-2-yl/H, –(CH₂)₄–, –CH(CH₂)₄CH(CH₂)₂–] from the acylation reactions of acetals (1) with trichloroacetyl chloride or trifluoroacetic anhydride in the presence of equimolar amounts of pyridine and imidazolium based ionic liquid ([BMIM][BF₄] or [BMIM][PF₆]) is reported. The reaction time, yields and IL recyclation are also investigated and this method showed advantages over the methods described in the literature.