Asymmetric hydrogenation of β-ketoamides 1a-i using chiral Ru(II)-catalysts with BINAP, MeO-BIPHEP, SYNPHOS and DIFLUORPHOS as atropisomeric ligands leads to the corresponding β-hydroxyamides 2a-i with good chemical yields (75% to 95%) and high enantioselectivities (73% to 99%) under 5 to 10 bar of hydrogen pressure.
T. Gmiza, R. Touati, C. Deport, V. Ratovelomanana-Vidal, J.P. Genet, B. Ben Hassine
catalysts, ruthenium, hydrogenation, enantioselectivity
An effective three-step sequence for the preparation of β-substituted α-(acetoxymethypcyclopent-2-en-1-one via oxidative allylic transposition of the allylic alcohols, is reported. This procedure is successfully applied for the preparation of a fragrant compound.
R. Gatri, R. Gatri, F. Rezgui, M. M. El Gaïed
Baylis-Hillman, cyclopent-2-en-1-one, allylic transposition, fragrance
The effect of changes of reaction variables upon cyanoethylation of alfa fibers by acrilonitrile were studied. The examined parametres were concentration of sodium hydroxide, reaction time and reaction temperature. A FTIR and elementary analysis were performed to show the partial substitution of the cellulose hydroxyl groups by cyanoethyl groups. The results demontrate that there is a steady increase of the reaction rate with increase of these reaction variables. The mechanical properties of cyanoethylated fibers of alfa were studied. The results show that the stress and stiffness of cyanoethylated fibers decrease with the increase of the extent of cyanoethylation.
M. Ben Abderrahman, R. Ben Cheikh
alfa fiber, cellulose, cyanoethylation, hydrophily, mechanical properties
The ring opening reaction of oligoethylene glycols diglycidyl ethers with potassium perfluoropropanoate allows the synthesis of bis(F-alkylcarbetoxymethylated) polyoxyethylene glycols in good yields. The obtained derivatives may be used as precursors in the preparation of F-alkyl non ionic surfactants.
L. Aroua, A. Baklouti
Oligoethylene glycols diglycidyl ethers, potassium perfluoropropanoate, F-alkyisurfactants
This paper is a contribution to the synthesis of functionalized bis-2,2'-(2-octyloxyphenoxy)-diethyl ether (RO5). Nitro, acetamido, bromo and cyano groups were fixed on the aromatic rings. Novel di and tétra substituted derivatives of RO5 were synthesized. The substituted ligands were characterized by IR, UV, 1H-NMR, 13C-NMR and MS. Furthermore, we have tested these molecules for their complexing properties for alkali cations by the determination of extraction equilibrium constants (Kex) and the complexation constants (Kc).
N. Drissi, F. Meganem
Bis-2,2'-(2-octyloxyphenoxy)-diethyl ether, Functionalization, Extraction, Complexation
A new series of F-alkyl α-bromoesters oligoethoxylated monoalkyled have been prepared by action of alcohols oligoethoxylated on perfluoroalkyl α-bromoacids.
B. Jedidi Yaïch, K. Debbabi, A. Baklouti
F-alkyl, oligoethoxylated, surfactants
The aldolic condensation of furfural (F) on acetone (Ac) allows to obtain a high added value product, the 4(2-furyl)-3-buten-2-one (FAc), used as a flavour in several industries. An important work has been done to identify the products formed and to develop analytical measurement methods. Product analysis during experiments carried out under various operating conditions, allowed to have the necessary data for the stoichio-kinetic modeling. Once the model is established, optimization procedure allows to determine the optimal operating conditions of FAc production.
N. Fakhfakh, P. Cognet, M. Cabassud
furfural, aldolic condensation, chromatography, stoichio-kinetic modelling, discontinuous reactor
1,3-dipolar cycloaddition of 2-diazopropane on coumarine 2 done at 0°C leads to the corresponding pyrazoline 3. The oxidation of 3 by MnO2 led to the pyrazolenine 4. On the other hand, the same reaction is carried out under similar operating conditions with 2-arylidenindane-1,3-diones 5a-d, leading to a new and unexpected heterocyclic structures 6a-d.
M. Askri, N. Ben Hamadi, M. Msaddek, M.E. Rammah
2-diazopropane, oxydation, Δ2-pyrazoline, spiro-Δ3-(1,3,4)-oxadiazoline
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