Nathalie Bar

The Improved Synthesis of Enantiopure (S)-N-Arylmethyl-5-Oxoprolines

Abstract A mild procedure for the preparation of enantiopure N-alkylated (S)-(+)-5-oxoprolines 3a-r is described. The method starting from (S)-glutamic acid appears generally applicable to substrates with a wide range of substituents.

Base-Promoted Reactions in Ionic Liquid Solvent: Synthesis of Butenolides

Synthesis of 4-methyl-5,5-dialkyl-2-oxo-2,5-dihydrofuran-3-carbonitriles is reported herein, using potassium carbonate as a base in an ionic liquid (BMIM, BF4) as solvent. The system ionic liquid and base can be recovered and reused.

Blue highly fluorescent boron difluoride complexes based on phthalazine–pyridine

Three new boron difluoride complexes based on phthalazine–pyridine, denoted (6), (7) and (8), have been synthesized and their photophysical and electrochemical properties have been studied. Solutions of these new BF 2-complexes exhibit an intense blue fluorescence under UV light at low concentrations. Fluorescence quantum yields (QYs) have been determined by photoluminescence (PL) spectroscopy and decay times (t) by semi-empirical methods. QYs of (6), (7) and (8) vary from 25% to 79%. HOMO and LUMO energy levels have been estimated by cyclic voltammetry and PL spectroscopy. The HOMO and LUMO energy levels, at BA5.3 eV and BA2.3 eV, respectively, make these new complexes interesting candidates as blue emitters in OLED applications.

Phosphonated Polyethyleneimines (PEIP) as Multi-Use Polymers

GRAPHICAL ABSTRACT Abstract Polyethylenimines (PEI) are commercial hyperbranched polymers, which can be phosphonated into polyethylenimines (PEIP) by the method of Moedritzer–Irani under microwave irradiation. Totally phosphonated PEIP are very efficient resins for metal ions extraction, and are also excellent anti-corrosion agents of steel. Partially phosphonated PEIP stabilize the maghemite nanoparticles and form core-shells, which have been used as platforms for the immobilization of trypsin and β−cyclodextrin. Partially phosphonated PEIP also stabilize antibacterial silver nanoparticles.

Solvent-Free Condensation of Methyl Pyridinium and Quinolinium Salts with Aldehydes Catalyzed by DBU

Abstract Methylpyridinium and methylquinolinium salts were condensed under solvent-free conditions with aromatic aldehydes in the presence of 1,8-diazabicyclo[5.4.]undec-7-ene (DBU) as catalyst, by grinding at room temperature. The products are dyes or useful intermediates. The DBU can be easily recycled and reused. GRAPHICAL ABSTRACT

PHOSPHONATION OF 1,1'-BINAPHTHALENE-2,2'-DIOL (BINOL) : SYNTHESIS OF (R)- AND (S)-2,2'-DIHYDROXY-1,1'-BINAPHTHALENE-6,6'-DIYLDIPHOSPHONIC ACID

The synthesis of 6,6′-bis(diethoxyphosphoryl)-1,1′-binaphthalene-2,2′-diol 1 in racemic and chiral forms is described. This synthesis, which involves a palladium-assisted phosphonation step, allows study of the phosphonation of bromophenol as an electron-rich aryl bromide model. Furthermore, the synthesis of 2,2′-dihydroxy-1,1′-binaphthalene-6,6′-diyldiphosphonic acid 2, from its diester 1, leads to a key intermediate in the synthesis of hybrid organic-inorganic materials.

Green synthesis of aurones and related compounds under solvent-free conditions

3-Coumaranones were condensed with aldehydes on alumina or alumina–potassium fluoride without solvent under microwave irradiation or classical heating. Novel aurones and analogues bearing ferrocenyl, benzodioxole or benzodioxane groups were obtained in good yields without use of heavy metal reagents.

An efficient recyclable magnetic material for the selective removal of organic pollutants

Summary Wastewater cleaning strategies based on the adsorption of materials are being increasingly considered, but the wide variety of organic pollutants at low concentrations still makes their removal a challenge. The hybrid material proposed here consists of a zwitterionic polyethylenimine polymer coating a magnetic core. Polyethylenimine is phosphonated at different percentages by a one-step process and used to coat maghemite nanoparticles. It selectively extracts high amounts of cationic and anionic contaminants over a wide range of pH values, depending on the adjustable number of phosphonate groups introduced on the polymer. After recovering the nanoparticles with a magnet, pollutants are quantitatively released by repeated washing with low amounts of pH-adjusted water. The material can be reused many times without noticeable loss of efficiency and is designed to resist high temperatures, oxidation and harsh conditions.

Catalyzed reaction of enaminonitrile with primary amines by SbF3: synthesis of new 2-aminosubstituted-pyridine-fused δ-lactones

A novel methodology for the synthesis of substituted 2-aminopyridine δ-lactones is reported. It involves the reactions of enaminonitrile, 4,6,6-trimethyl-2-oxo-5,6-dihydro-2H-pyran-3-carbonitrile, with amines which is catalyzed by antimony trifluoride SbF3. The structures of the new compounds obtained were characterized by various spectroscopic methods (IR, H NMR, C NMR and MS).

Synthesis of 4-arylideneisochroman-1,3-dione under microwave irradiation †

Homophthalic acid (1) and arylcarboxyaldehydes were condensed to form 4-arylideneisochroman-1,3-dione (3) in acetic anhydride in the presence of ammonium acetate under focused microwave irradiation. The stereochemistry of the products was determined by NMR and by X-ray diffraction of one isomer.