Synthesis, Characterization, Antimicrobial Activity, and Docking Studies of New Triazolic Tripodal Ligands.

The synthesis and characterization of new N-donor bitriazolic tripods were reported. The in vitro antibacterial and antifungal activities of these products were screened against fungal strain (Candida pelliculosa) and against four bacterial strains (Micrococcus luteus, Bacillus subtilis, Listeria innocua, and Escherichia coli). Biological data revealed the effect of the chemical structure on antimicrobial activity.

Click reactions as a key step for an efficient and selective synthesis of D-xylose-based ILs.

D-Xylose-based ionic liquids have been prepared from D-xylose following a five steps reaction sequence, the key step being a click cycloaddition. These ionic liquids (ILs) have been characterized through classical analytical methods (IR, NMR, mass spectroscopy, elemental analysis) and their stability constants, Tg and Tdec, were also determined. Considering their properties and their hydrophilicity, these compounds could be alternative solvents for chemical applications under mild conditions.

Cyclopropyl-tryptamine analogues: synthesis and biological evaluation as 5-HT(6) receptor ligands.

Conformational restrictions: Based on the pharmacophore model for 5-HT(6) receptor ligands (shown), tryptamine analogues bearing a cyclopropyl ring on the α-position of the tryptamine side chain were synthesized and evaluated against 5-HT receptors. N,N-Dimethyl-1-arylsulfonyltryptamine derivatives exhibited promising selectivity for 5-HT(6) over 5-HT(1a) and 5-HT(4) receptors and interesting activity against 5-HT(6) (K(i) =∼0.15 μM; IC(50) =∼0.

Ion-exchange centrifugal partition chromatography: a methodological approach for peptide separation.

This article presents the scope and optimization strategies employed in ion-exchange centrifugal partition chromatography (IXCPC). Both the weak and the strong modes were used to separate the constituents of a model mixture of dipeptides. Thus, the combined use of the quaternary biphasic solvent system, methyl-tert-butylether/acetonitrile/n-butanol/water (2:1:2:5, v/v) in the descending mode, of the lipophilic di(2-ethylhexyl)phosphoric acid (DEHPA) cation-exchanger, and of two displacers: calcium chloride and hydrochloric acid, has proven to be efficient for the preparative separation of the model mixture of five dipeptides (GG, GY, AY, LV and LY, in the order they were collected).

Homogeneous photocatalytic reactions with organometallic and coordination compounds--perspectives for sustainable chemistry.

Since the time of Giacomo Ciamician at the beginning of the 20th century, photochemical transformations have been recognized as contributing to sustainable chemistry. Electronic excitation significantly changes the reactivity of chemical compounds. Thus, the application of activation reagents is frequently avoided and transformations can be performed under mild conditions.

High-resolution and high-sensitivity 2D homonuclear J-resolved NMR spectroscopy.

This paper describes the implementation of the pure absorption ALPESTRE processing of 2D homonuclear J-resolved NMR spectra. The method relies on the computation of the missing information at negative evolution times by means of backward linear prediction. The paper also shows that resolution can be improved by application of time-symmetric apodization functions.

First domino radical cyclisation/Smiles rearrangement combination.

An unprecedented domino radical cyclisation-Smiles rearrangement process affording 3-(2'-aryl-N-methyl acetamido)indolin-2-ones is presented. Experimental rationalisation of this approach and description of an unexpected tricyclic core are also handled.

New and old NMR experiments for the resonance assignment of complex oligosaccharides--application to a cyclodextrin derivative.

The complete assignment of the (1)H and (13)C sugar resonances in mono-3,6-anhydro-heptakis(2,3-O-methyl)-hexakis(6-O-methyl)-β-cyclodextrin, an asymmetrically functionalized β-cyclodextrin, was carried out by means of 2D NMR experiments. The TOCSY and the homonuclear multiple relay COSY spectra provided most of the (1)H assignments. The multiplicity edited HSQC and a set of F(1) selective HSQC-TOCSY and multiple relay HSQC-COSY spectra gave access to most of the (13)C chemical shifts.

Photochemical electron transfer mediated addition of naphthylamine derivatives to electron-deficient alkenes.

Using photochemical electron transfer, N,N-dimethylnaphthylamine derivatives are added to α,β-unsaturated carboxylates. The addition takes place exclusively in the α-position of electron-deficient alkenes and mainly in the 4-position of N,N-dimethylnaphthalen-1-amine. A minor regioisomer results from the addition in the 5-position of this naphthylamine.

Glycerol and glycerol carbonate as ultraviscous solvents for mixture analysis by NMR.

NMR of weakly polar analytes in an apolar ultraviscous solvent has recently been proposed for mixture analysis as a pertinent alternative to the DOSY experiment. The present article reports the first use of glycerol and glycerol carbonate as polar solvents for the NMR analysis of a model mixture of dipeptides. This work demonstrates the high potentiality of these solvents for the analysis of mixtures made of polar and potentially bioactive compounds.

Enantioselective organocatalytic Friedel-Crafts alkylation reaction of indoles with 5-hydroxyfuran-2(5H)-one: access to chiral γ-lactones and γ-lactams via a Ugi 4-center 3-component reaction.

5-Hydroxyfuran-2(5H)-one 1, a readily available renewable resource, was used as an electrophile in the Friedel-Crafts alkylation of indoles catalyzed by a diphenylprolinol silyl ether. Moderate catalyst loading was achieved because of the high reactivity of 5-hydroxyfuran-2(5H)-one 1 in this process. Reduction of the Friedel-Crafts adduct (FC adduct) afforded indoyl lactones in high yield and enantioselectivity.

Intensified extraction of ionized natural products by ion pair centrifugal partition extraction.

The potential of centrifugal partition extraction (CPE) combined with the ion-pair (IP) extraction mode to simultaneously extract and purify natural ionized saponins from licorice is presented in this work. The design of the instrument, a new laboratory-scale Fast Centrifugal Partition Extractor (FCPE300(®)), has evolved from centrifugal partition chromatography (CPC) columns, but with less cells of larger volume. Some hydrodynamic characteristics of the FCPE300(®) were highlighted by investigating the retention of the stationary phase under different flow rate conditions and for different biphasic solvent systems.

Chitin synthase, a fungal glycosyltransferase that is a valuable antifungal target.

During the last 30 past years, more life-threatening fungal infections have appeared due to the increasing frequency of patients with weakened immune systems. Inhibition of fungal enzymes involved in the biosynthesis of sterols is considered to be a safe and effective option for antifungal therapy. However, the intensive use of sterol-biosynthesis inhibitors for years has resulted in resistance development.

Enhancing U(eff) in oxime-bridged [Mn(III)6Ln(III)2] hexagonal prisms.

The first 3d-4f clusters built using derivatised salicylaldoximes (R-saoH(2)) describe unusual hexagonal prisms. Replacement of the paramagnetic Gd(III) ions with diamagnetic Ln(III) ions allows for a more thorough understanding of the magnetic properties, whilst replacement with Tb(III) doubles U(eff).

The stimulating adventure of KRN 7000.

Associated with the CD1d protein, KRN 7000, a potent synthetic α-galactosylceramide, is known to activate the invariant NKT immune cells. This stimulation then leads to the production of different cytokines modulating a T(H)1/T(H)2 immune response balance involved in protection against several pathologies such as autoimmune diseases and cancers. Various efforts have been made toward the synthesis of simple and more functionalized analogues in order to selectively induce T(H)1 or T(H)2-type cytokine production.

Use of the NEO strategy (Nucleophilic addition/Epoxide Opening) for the synthesis of a new C-galactoside ester analogue of KRN 7000.

Our goal in the search for potentially bioactive analogues of KRN 7000 was to design an easy synthetic approach to a library of analogues using a strategy recently developed in our laboratory based on a Nucleophilic addition followed by an Epoxide Opening (the NEO strategy). Through the use of a common pivotal structure, a new C-galactoside ester analogue (23) was synthesized which showed an encouraging T(H)2 biased response during preliminary biological tests.

Copper(II) influence on flumequine retention in soils: macroscopic and molecular investigations.

The coadsorption of flumequine (fluoroquinolone antibiotic) and copper(II) on a alkaline soil sample (collected from the Champagne-Ardenne region, France) was studied at macroscopic and molecular scales by means of batch experiments and X-ray absorption spectroscopy. The retained antibiotic amount onto the soil surface increases (from 2- to >20-fold) with the copper concentration due to the formation of a Cu(II)-flumequine ternary surface complex, which leads to the accumulation of flumequine into soils. Flumequine can be classified at environmentally relevant pH values as a slow-mobile compound in soils and a very slow-mobile compound in the presence of copper, even at relatively low concentrations.

Synthesis and photochemical behavior of the tetrazolo tautomer of 2-azido-4-pyrimidinone-2'-deoxyriboside.

The 2-azido analogue of 2'-deoxyuridine was prepared in three steps from 2'-deoxy-2-thiouridine. The sulfur atom of the 2-thio nucleoside was methylated and then displaced by hydrazine to furnish the corresponding 2-hydrazino derivative. After diazotization, the 2-azido compound that exists as its tetrazolo tautomer was obtained.

Enantiomerically pure 2-aryl(alkyl)-2-trifluoromethylaziridines: synthesis and ring opening with selected O- and N-nucleophiles.

We report herein the synthesis of enantiomerically pure 2-phenyl- and 2-ethyl-2-trifluoromethylaziridines by Mitsunobu-type cyclisation of the corresponding N-protected amino alcohols, and our results regarding their ring opening with selected nucleophiles. Under basic conditions, N-tosyl aziridines have been regioselectively opened at the less hindered carbon. Under acidic conditions, the regioselectivity of the attack depends on the nature of the substituent at C-2 and on the nitrogen protecting group.

Synthesis of trifluoromethyl cyclohexyl, cyclohexenyl and aryl compounds via stepwise Robinson annulation.

The diketone 2-fluoro-2-(trifluoromethyl)-1-phenylhexane-1,5-dione 3 was synthesized by a Mukaiyama Michael type reaction from the corresponding tetrafluoroenol silyl ether prepared from pentafluoropropiophenone. This diketone was treated under basic conditions and was converted, depending on the stoichiometry of the base, into the surprisingly stable ketol 4-fluoro-4-(trifluoromethyl)-3-hydroxy-3-phenylcyclohexanone 4 as a single diastereomer (catalytic KOH) or to the biphenylol 6-(trifluoromethyl)biphenyl-3-ol (excess KOH, THF) 5. Solvolysis of the trifluoromethyl group (anionic activation) occurred using excess KOH in alcohol.

Low catalyst loadings for the production of carboxylic acids from polysaccharides and hydrogen peroxide.

The oxidation of starch, xylans, potato flesh and wheat flour by H(2)O(2), in the presence of MSO(4) (M=Cu, Fe) as catalyst, led to depolymerization, and formation of solutions containing polyhydroxycarboxylic acids. Some of these oxidized compounds facilitate the process, leading to efficient transformations even with very low amounts of catalyst.

Synthesis and biological evaluation of new penta- and heptacyclic indolo- and quinolinocarbazole ring systems obtained via Pd(0) catalysed reductive N-heteroannulation.

A short route, involving a tetramolecular condensation reaction and a Pd/C catalyst-H(2)-mediated reductive N-heteroannulation as the key-steps, has been found for the synthesis of some new penta- and heptacyclic indolo- (12), quinolino- (13) and indoloquinolinocarbazole (11) derivatives. HF-DFT (B3LYP) energy profiles and NMR calculations were carried out to help in the understanding of the experimental results. N-Alkylated indoloquinolinocarbazoles (16b, 17a, 17b and 18) were prepared and screened essentially toward some cancer-(G-quadruplex, DNA, topoisomerase I) and CNS-related (kinases) targets.