Jean Pierre Bazureau
University of Rennes
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Featured researches published by Jean Pierre Bazureau.
Catalysis Communications | 2002
Joan Fraga-Dubreuil; Khadidja Bourahla; Mustapha Rahmouni; Jean Pierre Bazureau; Jack Hamelin
Esterification reactions of acetic acid, methoxyacetic acid and methylmalonic acid with neo-pentanol, hexanol, heptanol and decanol have been investigated in three ionic liquids with hydrogen sulphate, dihydrogen phosphate as counteranions and also two ionic liquids modified with HPF6 as catalyst. The nature of both the counteranion and cation influence the behavior of the catalyst. Good yields and high selectivities were obtained and all the produced esters could be easily recovered due to their immiscibility with the ionic liquid as green reaction medium. 2002 Elsevier Science B.V. All rights reserved.
Tetrahedron Letters | 2000
Joan Fraga Dubreuil; Jean Pierre Bazureau
The 1,3-dipolar cycloaddition reactions between imidate 1 derived from diethyl aminomalonate and 2-ethoxybenzaldehyde 2 as dipolarophile has been investigated in various air and moisture stable ionic liquids. Significant rate enhancements and improved yields at 70°C have been observed with [emim][BF4] and [emim][NfO] ionic liquids. The reactivity of dipolarophiles covalently grafted on the ionic liquids were also evaluated.
Tetrahedron Letters | 2001
Joan Fraga-Dubreuil; Jean Pierre Bazureau
Abstract The preparation and applications in the Knoevenagel and 1,3-dipolar cycloaddition reactions of new grafted soluble liquid phases derived from imidazolium ionic liquids are described. Good yields and high regioselectivity are the features observed with these unconventional liquid phases.
Tetrahedron | 2003
Joan Fraga-Dubreuil; Jean Pierre Bazureau
Abstract The first report of the use of task-specific ionic liquid as synthetic equivalent of ionic liquid-phase matrice for the preparation of a small library of 4-thiazolidinones is reported in this paper. The starting (ethyleneglycol)ionic liquid-phase is functionalized in good yields with 4-(formylphenoxy)butyric acid by using usual esterification reaction conditions (DCC/DMAP as catalyst). The synthesis of the ionic liquid-phase bound 4-thiazolidinones was performed by a one-pot three-component condensation under microwave dielectric heating. The final cleavage under microwave/catalysis strategy provides the expected 4-thiazolidinones in high purity after flash-chromatography purification. According to the ionic liquid-phase organic synthesis (IoLiPOS) methodology, it was found that optimized reaction conditions were performed by standard analytical methods (NMR, TLC). The 1H, 13C NMR spectrum of some representative 4-thiazolidinones and ionic liquid-phase bound benzaldehyde are also reported.
Journal of Medicinal Chemistry | 2012
Tania Tahtouh; J.M. Elkins; Panagis Filippakopoulos; Meera Soundararajan; Guillaume Burgy; Emilie Durieu; Claude Cochet; Ralf S. Schmid; Donald C. Lo; Florent Delhommel; Anselm Erich Oberholzer; Laurence H. Pearl; François Carreaux; Jean Pierre Bazureau; Stefan Knapp; Laurent Meijer
DYRKs (dual specificity, tyrosine phosphorylation regulated kinases) and CLKs (cdc2-like kinases) are implicated in the onset and development of Alzheimers disease and Down syndrome. The marine sponge alkaloid leucettamine B was recently identified as an inhibitor of DYRKs/CLKs. Synthesis of analogues (leucettines) led to an optimized product, leucettine L41. Leucettines were cocrystallized with DYRK1A, DYRK2, CLK3, PIM1, and GSK-3β. The selectivity of L41 was studied by activity and interaction assays of recombinant kinases and affinity chromatography and competition affinity assays. These approaches revealed unexpected potential secondary targets such as CK2, SLK, and the lipid kinase PIKfyve/Vac14/Fig4. L41 displayed neuroprotective effects on glutamate-induced HT22 cell death. L41 also reduced amyloid precursor protein-induced cell death in cultured rat brain slices. The unusual multitarget selectivity of leucettines may account for their neuroprotective effects. This family of kinase inhibitors deserves further optimization as potential therapeutics against neurodegenerative diseases such as Alzheimers disease.
Journal of Medicinal Chemistry | 2011
Mansour Debdab; François Carreaux; Stéven Renault; Meera Soundararajan; Oleg Fedorov; Panagis Filippakopoulos; Olivier Lozach; Lucie Babault; Tania Tahtouh; Blandine Baratte; Yasushi Ogawa; Masatoshi Hagiwara; Andreas Eisenreich; Ursula Rauch; Stefan Knapp; Laurent Meijer; Jean Pierre Bazureau
We here report on the synthesis, optimization, and biological characterization of leucettines, a family of kinase inhibitors derived from the marine sponge leucettamine B. Stepwise synthesis of analogues starting from the natural structure, guided by activity testing on eight purified kinases, led to highly potent inhibitors of CLKs and DYRKs, two families of kinases involved in alternative pre-mRNA splicing and Alzheimers disease/Down syndrome. Leucettine L41 was cocrystallized with CLK3. It interacts with key residues located within the ATP-binding pocket of the kinase. Leucettine L41 inhibits the phosphorylation of serine/arginine-rich proteins (SRp), a family of proteins regulating pre-RNA splicing. Indeed leucettine L41 was demonstrated to modulate alternative pre-mRNA splicing, in a cell-based reporting system. Leucettines should be further explored as pharmacological tools to study and modulate pre-RNA splicing. Leucettines may also be investigated as potential therapeutic drugs in Alzheimers disease (AD) and in diseases involving abnormal pre-mRNA splicing.
Tetrahedron | 1995
Jean Michel Lerestif; Jacques Perrocheau; François Tonnard; Jean Pierre Bazureau; Jack Hamelin
Abstract Imidates derived from α-amino esters as potential azomethine ylides, undergo 1,3-dipolar cycloaddition with imino-alcohols, in tautomeric equilibrium with 1,3-oxazolidines, without solvent at 70°C or under microwave irradiation. This reaction leads to a wide range of novel polyfunctionalized 4-yliden-2-imidazolin-5-ones in good yields with short reaction times. The reactivity of these imidates derived from α-amino esters with imino-alcohols is rationalized from the energy of the Frontier Molecular Orbitals (FMO) determined by semi-empirical PM3 calculations: the reaction is controlled by the interaction HOMO (1,3-dipole) - LUMO (dipolarophile) and the second order pertubation energy calculations are in agreement with the experimental reaction orientation.
Tetrahedron | 1997
Jean Michel Lerestif; Loïc Toupet; Sourisak Sinbandhit; F. Tonnard; Jean Pierre Bazureau; Jack Hamelin
Abstract The 1,3-dipolar cycloadditions between imidate 1, derived from dimethylaminomalonate and aldehydes 2(a-f), phthalaldehyde 2g, isophthalaldehyde 2h. 4-chlorophenylisocyanate 9a, ethoxycarbonylisothiocyanate 9d as dipolarophiles proceeds regioselectively in good yield using solvent-free conditions. Synthesis of ortho- and meta-bis-(2′-oxazoline-5′-yl)benzenes 6g, 6h are also reported. The regiochemistry and the reactivity in these cycloaddition reactions are rationalized by PM3 MO calculations. The stereoselective demethoxycarbonylation of dimethyl 2-oxazoline-4,4-dicarboxylate 4a is described. The mild hydrolysis of 5-(2-formylphenyl)-2-oxazoline 4g leads to the formation of a new 3,4-dihydroisoquinoline 8h in quantitative yield.
Russian Journal of Organic Chemistry | 2007
A. Arfan; Ludovic Paquin; Jean Pierre Bazureau
A simple and effective synthesis of 3,4-dihydropyrimidin-2(1H)-one and 3,4-dihydropyrimidine-2(1H)-thione derivatives has been developed on the basis of three-component condensation of substituted aromatic and heterocyclic aldehydes, methyl acetoacetate, and urea or thiourea in the presence of 10% of an acidic task-specific ionic liquid ([C4mim][HSO4]) as catalyst under microwave irradiation in the absence of a solvent. The proposed procedure ensures short reaction times (4.4–8 min) and good yields after purification by recrystallization.
Tetrahedron Letters | 1993
Jean Michel Lerestif; Jean Pierre Bazureau; Jack Hamelin
Abstract Imidates derived from α-amino esters, undergo cycloaddition reactions as stabilized ylides, with imines in good yields.