LG2A

Laboratoire de Glycochimie
et des Agroressources d'Amiens UR 7378

LG2A UR 7378

Nos tutelles

  • Tutelle UPJV

Nos Fédérations

  • Tutelle ICP

Intranet

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David LESUR

Ingénieur d'études en technique d'analyse chimique (IGE)

Mail :

Tel : 03 22 82 74 76

Fax : 03 22 82 75 60

Axes de recherche : Chimie pour le Développement Durable
et
Chimie pour le vivant

Activités

Responsable de la mise au point et du suivi des techniques de caractérisation et de purification pour les axes thématiques du Laboratoire LG2A  :

  • Suivi de synthèse en spectrométrie de masse (MS) et analyse chromatographique couplée à la spectromètrie de masse (LC/MS).
  • Mise au point de séparation des bruts réactionnels par chromatographie liquide (phase inverse ou normale) analytique puis transposition au stade semi-préparatif.
  • Caractérisation de composés organiques par spectrométrie de masse haute résolution (HR-MS) et par spectrométrie de masse en tandem (MS/MS).

Mises en place de contrats de prestations analytiques pour plusieurs entreprises privées

Compétences et Techniques

Chromatographie Liquide Haute Performance :

  • HPLC phase inverse : Waters 600, Waters prep LC 4000 équipée de  détecteurs à diffusion de lumière (DEDL), UV double longueurs d’ondes (Waters 2487) et barrette de diodes (Waters 2996).
  • HPLC Binaire Haute Pression 1525 équipée de détecteurs UV double longueur d’ondes (Waters 2487) et DeDL (Waters 2424).
  • HPLC phase normale : waters 590 équipée de détecteurs UV double longueur d’ondes (Waters  2487) et réfractomètre (WatersR401).
  • HPLC haute pression phase inverse : Waters 1595 équipée d’un détecteur UV double longueurs d’ondes (Waters 2487).
  • IC (Chromatographie Ionique) : Dionex ICS 3000 double pompe équipée de détecteurs d’ampérométrique (PAD) et conductimétrique et d’un suppresseur pour réaliser des couplages IC/MS.
  • LC/MS : Alliance 2695 couplée à un spectromètre de masse (ZQ4000).
  • Systèmes d'autopurification avec détection PDA, MS ou DEDL
  • Chromatographies Flash Buchi avec détection UV et DEDL

Spectrométrie de masse :

  • ZQ 4000 (ESI-MS et LC / ESI-MS)
  • QTOF Synapt G2Si ESI et MALDI, MS, HRMS et IMS
  • QTOF ESI Ms, HRMS, IMS
  • Orbitrap avec source ESI et NanoESI
  • LC MS/MS avec source ESCI (TQS)

RMN

  • Brucker 400MHz et 600 MHz.

Infrarouge

  • Nicolet AVATAR 320 FT-IR équipé d’un accessoire ATR OMNI-Sampler.
  • Shimadzu IRAffinity-1S (IR) et MIRacle 10 (ATR)
  • Spectrophotomètrie UV JASCO V-630

Activités secondaires :

  • Expert CIR (Crédit Impôt Recherche) pour le ministère de l'enseignement supérieur et de la Recherche depuis 2016
  • Expert concours ITRF (IGE, ASI, TECH, ADT) depuis 2007
  • Consultant Analytique pour différentes entreprises privées

Enseignements en Techniques d'analyses

  • 50 UC
  • Co-responsable du MASTER TVRN spécialité ACQ

Sélection de publications


Mass Spectrometry, Ion Mobility Separation and Molecular Modelling: A Powerful Combination for the Structural Characterisation of Substituted Cyclodextrins Mixtures
Rigaud, S.; Dosso, A.; Lesur, D.; Cailleu, D.; Mathiron, D.; Pilard, S.; Cezard, C.; Djedaini-Pilard, F.
Int J Mol Sci 2022, 23, 13352.
When working on the synthesis of substituted cyclodextrins (CDs), the main challenge remains the analysis of the reaction media content. Our objective in this study was to fully characterise a complex isomers mixture of Lipidyl-betaCDs (LipbetaCD) obtained with a degree of substitution 1 (DS = 1) from a one-step synthesis pathway. The benefit of tandem mass spectrometry (MS/MS) and ion mobility separation hyphenated with mass spectrometry (IM-MS) was investigated. The MS/MS fragment ion's relative intensities were analysed by principal component analysis (PCA) to discriminate isomers. The arrival time distribution (ATD) of each isomer was recorded using a travelling wave ion mobility (TWIM) cell allowing the determination of their respective experimental collision cross section (CCSexp). The comparison with the predicted theoretical CCS (CCSth) obtained from theoretical calculations propose a regioisomer assignment according to the betaCD hydroxyl position (2, 3, or 6) involved in the reaction. These results were validated by extensive NMR structural analyses of pure isomers combined with molecular dynamics simulations. This innovative approach seems to be a promising tool to elucidate complex isomer mixtures such as substituted cyclodextrin derivatives.
https://dx.doi.org/10.3390/ijms232113352


Copper-uptake mediated by an ecofriendly zwitterionic ionic liquid: A new challenge for a cleaner bioeconomy
Vuillemin, M. E.; Waterlot, C.; Verdin, A.; Laclef, S.; Cézard, C.; Lesur, D.; Sarazin, C.; Courcot, D.; Hadad, C.; Husson, E.; Van Nhien, A. N.
Journal of Environmental Sciences 2022.
This study aims to investigate the ability of an imidazolium biobased Zwitterionic Ionic Liquids (ZILs) in enhancing the phytoavailability of copper from garden (G) and vineyard (V) soils using the model plant ryegrass. Uncontaminated and artificially contaminated CuSO4 soils, unamended and ZIL-amended soil modalities were designed. The copper/ZIL molar ratio (1/4) introduced was rationally established based on molecular modeling and on the maximal copper concentration in artificially contaminated soil. Higher accumulation of copper in the shoots was detected for the uncontaminated and copper contaminated ZIL amended V soils (18.9 and 23.3 mg.kg−1, respectively) contrary to G soils together with a ZIL concentration of around 3% w/w detected by LC-MS analyses. These data evidenced a Cu-accumulation improvement of 38 and 66% compared to non-amended V soils (13.6 and 13.9 mg.kg−1 respectively). ZIL would be mainly present under Cu(II)-ZIL4 complexes in the shoots. The impact on the chemical composition of shoot were also studied. The results show that depending on the soils modalitity, the presence of free copper and/or ZIL led to different chemical compositions in lignin and monomeric sugar contents. In the biorefinery context, performances of enzymatic hydrolysis of shoots were also related to the presence of both ZIL and copper under free or complex forms. Ecotoxicity assessment of the vineyard soil samples indicated that the quantity of copper and ZIL remaining in the soils had no significant toxicity. ZIL amendment in a copper-contaminated soil was demonstrated as being a promising way to promote the valorization of phytoremediation plants.
https://dx.doi.org/10.1016/j.jes.2022.10.011


Synthesis, characterization and in vivo antitumor effect of new α,β-unsaturated-2,5-disubstituted-1,3,4-oxadiazoles
Fray, M.; Elbini-Dhouib, I.; Hamzi, I.; Doghri, R.; Srairi-Abid, N.; Lesur, D.; Benazza, M.; Abidi, R.; Barhoumi-Slimi, T.
Synth. Commun. 2022, 1-12.
AbstractNew α,?-unsaturated-2,5-disubstituted-1,3,4-Oxadiazoles (4a?j) and (10a?d) have been prepared in good to excellent yields starting from ?-chlorovinyl aldehydes and hydrazide. The synthesized oxadiazoles were fully characterized by (1H, 13C) NMR, IR and HRM Sspectroscopic techniques. The in vivo antitumor activity of 4b, 4c, 4g, 4d, and 10c was evaluated. Biochemical measurements of serum alanine aminotransferase, aspartate aminotransferase and creatinine levels of mice injected with a dose of 20?mg/kg, of each selected compound, showed no toxic effect, neither in liver nor in kidney organs. However, hepato/nephrotoxicities were observed in mice treated with a dose of 100?mg/kg. When tested on melanoma in a mice xenograft model, the pharmacodynamic study indicated that the two compounds 4c, bearing a trifluoromethyl group and 10c, bearing a triazole moiety, are potent antitumoral agents at the safe dose of 20?mg/kg against B16-F10-induced melanoma.
https://dx.doi.org/10.1080/00397911.2022.2053993


Synthesis of novel S- and O-disaccharide analogs of heparan sulfate for heparanase inhibition
Koffi Teki, D. S. E.; Coulibaly, B.; Bil, A.; Vallin, A.; Lesur, D.; Fanté, B.; Chagnault, V.; Kovensky, J.
Org. Biomol. Chem. 2022.
Heparan sulfate (HS), a glycosaminoglycan related to heparin, is a linear polysaccharide, consisting of repeating disaccharide units. This compound is involved in multiple biological processes such as inflammation, coagulation, angiogenesis and viral infections. Our work focuses on the synthesis of simple HS analogs for the study of structure–activity relationships, with the aim of modulating these biological activities. Thioglycoside analogs, in which the interglycosidic oxygen is replaced by a sulfur atom, are very interesting compounds in terms of therapeutic applications. Indeed, the thioglycosidic bond leads to an improvement of their stability and can allow the inhibition of enzymes involved in physiological and pathological processes. In our previous work, we developed a synthetic sequence which led to a non-sulfated thiodisaccharide analog of HS. In this paper, we report our results of the development of a new synthetic method allowing access to the novel sulfated S-disaccharide, as well as to their oxygenated analogues (O-disaccharide and sulfated O-disaccharide). These 4 compounds were also tested for the inhibition of heparanase, an enzyme involved in biological processes like tumor growth and inflammation. The obtained IC50 values in the micromolar range showed the impact of the interglycosidic sulfur atom and the 6-sulfate group.
https://dx.doi.org/10.1039/d2ob00250g


Heteroglycoclusters through Unprecedented Orthogonal Chemistry Based on N-Alkylation of N-Acylhydrazone
Fray, M.; Mathiron, D.; Pilard, S.; Lesur, D.; Abidi, R.; Barhoumi-Slimi, T.; Cragg, P. J.; BENAZZA, M.
Eur. J. Org. Chem. 2022
Orthogonal chemistry is a valuable tool in the preparation of complex molecules as heteroglycoclusters. Unfortunately, selective heteroconjugation of multifunctional starting materials remains a usually challenging problem to overcome. Herein, we report the first use of N -alkylation of N -acylhydrazone as a key step in the orthogonal synthesis. Sequentially associated with the azido-alkyne click chemistry, it stands out as a new and straightforward synthetic method of glycoconjugate small molecules, heterodisaccharides, and heteroglycoclusters based on cone p - t Bu-calix[4]arene and 1,3- alt p - t Bu-thiacalix[4]arene with
https://doi.org/10.1002/ejoc.202101537


Synthesis and interfacial properties of new 6-sulfate sugar-based anionic surfactants
Abdellahi, B.; Bois, R.; Golonu, S.; Pourceau, G.; Lesur, D.; Chagnault, V.; Drelich, A.; Pezron, I.; Nesterenko, A.; Wadouachi, A.
Tetrahedron Lett. 2021, 153113.
Three families of anionic sugar-based surfactants bearing a sulfate functional group on the primary position of a monosaccharide were synthesized and their physicochemical properties were compared. The first family corresponds to 6-sulfate derivatives of commercially available octa- and dodecyl β-D-gluco- and galactopyranosides. The second and the third families contain an amide linker between the sulfated monosaccharide (galactose, glucose or xylose) and the hydrophobic alkyl chain. Twelve of the as-synthesized anionic glycolipids, including nine novel sulfated compounds, were investigated for their surface activity at the air/liquid interface and for their self-assembling properties. These sugar-based surfactants show surface properties similar to those of commercial anionic surfactants (SDS and SLES) with good ability to reduce surface tension. The obtained results confirm the interest in these new bio-based molecules for potential substitution of anionic surfactants in various formulations.
https://dx.doi.org/10.1016/j.tetlet.2021.153113


A simple procedure to obtain a medium-size oligogalacturonic acids fraction from orange peel and apple pomace wastes
Cano, M. E.; García-Martín, A.; Ladero, M.; Lesur, D.; Pilard, S.; Kovensky, J.
Food Chem. 2021, 346, 128909.
Pectin oligosaccharides, which can be obtained from fruit wastes, have proven their potential as plant immune-system elicitors. Although the precise size of active species is still under investigation, medium size oligosaccharides have been reported as the most active. Three defined oligogalacturonic acid (OGAs) mixtures were produced from commercial pectin, orange peel and apple pomace residues. The methodology developed involves two sequential acid treatments followed by stepwise ethanol precipitation. Without the need of chromatographic separations, three different fractions were obtained. The fractions were analyzed by high performance anion exchange chromatography (HPAEC) and were completely characterized by mass spectrometry, showing that the small size, medium size and large size fractions contained OGAs of degree of polymerization 3 to 9, 6 to 18, and 16 to 55, respectively.
https://dx.doi.org/10.1016/j.foodchem.2020.128909


Synthesis of defined oligohyaluronates-decorated liposomes and interaction with lung cancer cells
Cano, M. E.; Lesur, D.; Bincoletto, V.; Gazzano, E.; Stella, B.; Riganti, C.; Arpicco, S.; Kovensky, J.
Carbohydr. Polym. 2020, 248, 116798.
In this work hyaluronic acid (HA) oligosaccharides with degree of polymerization (DP) 4, 6 and 8, obtained by enzymatic depolymerization of HA, were conjugated to a PEG-phospholipid moiety. The products (HA-DP4, HA-DP6 and HA-DP8) were used to prepare decorated liposomes. The cellular uptake of HA-DP4, HA-DP6 and HA-DP8-decorated fluorescently labelled liposomes was significantly higher (12 to 14-fold) in lung cancer cell lines with high CD44 expression than in those with low CD44 expression, suggesting a receptor-mediated entry of HA-conjugated formulations. Competition assays showed that the uptake followed this rank order: HA-DP8>HA-DP6>HA-DP4 liposomes. Moreover, they are capable of a faster interaction with CD44, followed by phagocytosis, than HA liposomes obtained from HA of higher molecular weight (4800 and 14800 Da). HA-DP4, HA-DP6 and HA-DP8-liposomes did not show cytotoxicity or inflammatory effects. Overall, we propose our new HA-DP oligosaccharides as biocompatible and effective tools for a potential drug delivery to CD44-positive cells.
https://dx.doi.org/10.1016/j.carbpol.2020.116798


Solvent- and catalyst-free transamidations of unprotected glycosyl carboxamides
Bensalah, F. O.; Bil, A.; Wittine, K.; Bellahouel, S.; Lesur, D.; Markovic, D.; Laclef, S.
Org. Biomol. Chem. 2019.
The transamidation reactions of unprotected mono- and disaccharidic carboxamides with various primary and secondary arylic, heterocyclic or aliphatic amines are described. This new method is green and atom efficient and gives good to high yields. Notably, the conditions do not require either a solvent or a catalyst and give ammonia as a single by-product. The described coupling reaction is compatible with a variety of functional groups and was used in the synthesis of various glycosidic derivatives and biologically relevant glycolipids. A plausible reaction mechanism involving an intermolecular H-bond activation of the starting carboxamides is proposed.
https://dx.doi.org/10.1039/C9OB02096A


High resolution MALDI-TOF-MS and MS/MS: Application for the structural characterization of sulfated oligosaccharides
Lesur, D.; Duhirwe, G.; Kovensky, J.
Eur. J. Mass Spectrom. 2019, 0.
Sulfated oligosaccharides are involved in important biological events that are often modulated by specific sequences and sulfation patterns, but their structural analysis remains challenging. Matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) analysis of three different sulfated oligosaccharides (Fondaparinux, the octasulfated pentasaccharide, a disulfated heparin-derived tetrasaccharide 1, and an octasulfated maltoheptaose) 2 was performed using the 2-(4-hydroxyphenylazo)benzoic acid-tetramethylguanidinium (HABA-TMG2) matrix. High resolution mass spectrometry of the main ions observed was successful, and this was complemented by tandem mass spectrometry (MS/MS) analysis for structural assessment. Despite sulfate losses, fully sulfated molecular ions were observed and these allowed the determination of oligosaccharide structures: UA-GlcNAc-UA(2S)-AnhMan(6S) for compound 1 and (Glc6S)6-Glc (1S,6S) for compound 2.
https://dx.doi.org/10.1177/1469066719851438


Unprecedented thiacalixarene fucoclusters strong inhibitors of Ebola cis-cell infection and HCMV-gB glycopro-tein/DC-SIGN C-type lectin interaction
Taouai, M.; Porkolab, V.; Chakroun, K.; Cheneau, C.; Luczkowiak, J.; Abidi, R.; Lesur, D.; Cragg, P. J.; Halary, F.; Delgado, R.; Fieschi, F.; Benazza, M.
Bioconjug Chem 2019.
Glycan-protein interactions control numerous biological events from cell-cell recognition and signaling to pathogen host cell attachment for infections. To infect cells, some viruses bind to immune cells thanks to DC-SIGN (dendritic cell [DC]-specific ICAM3-grabbing non-integrin) C-type lectin expressed on dendrit-ic and macrophage cell membrane, via their envelope protein. Prevention of this infectious interaction is a serious therapeutic option. Here, we describe the synthesis of first water-soluble tetravalent fucocluster pseudopeptide-based thiacalixarene 1,3-alternate as viral antigen mimics designed for the inhibition of DC-SIGN, to prevent viral particle uptake. Their preparation exploits straightforward convergent strate-gies involving one pot Ugi four-component (Ugi-4CR) and azido-alkyne click chemistry reactions as key steps. Surface plasmon resonance showed strong inhibition of DC-SIGN interaction properties by tetrava-lent ligands designed with high relative potencies and beta avidity factors. All ligands block DC-SIGN active sites at nanomolar IC50 preventing cis-cell infection by Ebola viral particles pseudotyped with EBOV gly-coprotein (Zaire species of Ebola virus) on Jurkat cells that express DC-SIGN. In addition, we observed strong inhibition of DC-SIGN/human cytomegalovirus (HCMV)-gB recombinant glycoprotein interaction. This finding opens the way to the simple development of new models of water-soluble glycocluster-based thiacalixarene with wide range antimicrobial activities.
http://dx.doi.org/10.1021/acs.bioconjchem.9b00066


The effect of room temperature ionic liquids on the selective biocatalytic hydrolysis of chitin via sequential or simultaneous strategies
Husson, E.; Hadad, C.; Huet, G.; Laclef, S.; Lesur, D.; Lambertyn, V.; Jamali, A.; Gottis, S.; Sarazin, C.; Nguyen Van Nhien, A.
Green Chem. 2017, 19, 4122-4131.
An efficient conversion of chitin, the second most abundant renewable polymer on the Earth, into N-acetylglucosamine and N,N[prime or minute]-diacetylchitobiose, using room temperature ionic liquids (RTILs) and commercially available chitinases is described for the first time. The sequential strategy consists of the use of RTILs to pretreat chitin under mild conditions as a first step before enzymatic hydrolysis. [C2mim][OAc] (1-ethyl-3-methyl imidazolium) pretreatment provides an efficient production of N-acetylglucosamine (185.0 +/- 4.0 mg per g chitin) or N,N[prime or minute]-diacetylchitobiose (667.60 +/- 20.71 mg per g chitin) catalyzed by chitinase from Trichoderma viride or Streptomyces griseus, respectively. A thorough investigation of the structural changes of chitin induced by RTIL pretreatment suggested an increase in enzymes' accessibility to the chitin substrate. Alternatively, a one-pot enzymatic hydrolysis of chitin in [C2mim][OAc]-aqueous medium constitutes a promising simultaneous route to selectively generate N-acetylglucosamine or N,N[prime or minute]-diacetylchitobiose by decreasing the required [C2mim][OAc] amount and the number of steps. Finally, the combination of the two chitinases from T. viride and S. griseus was shown to be very relevant to considerably increase the production of N-acetylglucosamine up to 760.0 +/- 0.1 mg per g chitin.
http://dx.doi.org/10.1039/c7gc01471f


Chirality inversion, supramolecular hydrogelation and lectin binding of two thiolactose amphiphiles constructed on a di-lauroyl-l-tartaric acid scaffold
Cano, M. E.; Di Chenna, P. H.; Lesur, D.; Wolosiuk, A.; Kovensky, J.; Uhrig, M. L.
New J. Chem. 2017, 41, 14754-14765.
Herein we report the synthesis, characterization and self-assembly properties of two new thiolactose based amphiphiles constructed on a di-lauroyl-l-tartaric acid scaffold that only differ in the length of the spacer by an ethylene glycol unit. Upon dissolution in hot water the amphiphiles give rise to different colloidal systems at 25 [degree]C: the one with the shorter linker forms a supramolecular thermoreversible hydrogel at a concentration of 0.1 w/v% while the other renders a colloidal system at high dilution (0.005 w/v%). Dynamic Light Scattering, Electron Microscopy (TEM, SEM and E-SEM), fluorescence CMC determination, SAXS and Circular Dichroism experiments were used to characterize both systems. The experiments indicate that only the amphiphile carrying the shorter linker is able to form a crossed-linked network of micellar fibers and thus, a stable hydrogel is observed. The difference of an ethylene glycol unit in the spacer also causes the adoption of a different molecular assembly evidenced by the inversion of the self-assembled chiral arrangement. In addition, the amphiphiles were evaluated for their ability to bind to the PNA lectin using a turbidimetric method. Agglutination was observed in both cases, a process that was disrupted upon the addition of an excess of the disaccharide lactose.
http://dx.doi.org/10.1039/c7nj02941a


Arylnaphthalene and aryltetralin-type lignans in hairy root cultures of Linum perenne, and the stereochemistry of 6-methoxypodophyllotoxin and one diastereoisomer by HPLC-MS and NMR spectroscopy
Jullian-Pawlicki, N.; Lequart-Pillon, M.; Huynh-Cong, L.; Lesur, D.; Cailleu, D.; Mesnard, F.; Laberche, J. C.; Gontier, E.; Boitel-Conti, M.
Phytochem. Anal. 2015, 26, 310-9.
INTRODUCTION: Hairy root cultures of Linum sp. are an alternative for the high production of lignans. Linum perenne is known to produce arylnaphthalene-type lignans such as justicidin B, isojusticidin and diphyllin. OBJECTIVE: To elucidate the presence of aryltetralin-type lignan diastereoisomers, besides the known arylnaphthalene-type lignans, in hairy roots of Linum perenne, and to determine the configurations of one diastereoisomer of 6-methoxypodophyllotoxin (6-MPTOX). METHODS: Lignans from hairy root cultures of Linum perenne were extracted and separated by HPLC. Arylnaphthalene-type lignans were identified by LC-MS, according to the literature. Two diastereoisomers of aryltetralin-type lignans were analysed by mass spectrometry and NMR spectroscopy. RESULTS: Numerous arylnaphthalene-type lignans (diphyllin-2-hexose-pentose, diphyllin-3-pentose and diphyllin-hexose) were identified in hairy root cultures. Methoxypodophyllotoxin, an aryltetralin-type lignan, was also identified, as well as one diastereoisomer. This aryltetralin-type lignan could be derived via 7-hydroxymatairesinol as a hypothetical biosynthetic pathway. The stereochemical configurations of aryltetralin isomers were determined. CONCLUSION: Arylnaphthalene and two diastereoisomers of aryltetralin-type lignans are produced in Linum perenne hairy root cultures. Matairesinol, the precursor of justicidin B, also seems to be converted into 6-MPTOX via 7-hydroxymatairesinol. This is the first report of the stereochemical configurations of an aryltetralin-type lignan other than podophyllotoxin (PTOX).
http://dx.doi.org/10.1002/pca.2565


Alditol thiacrowns via a ring-closing metathesis of carbohydrate-derived α,ω-dithioallylethers
Benazza, M.; Danquigny, A.; Novogrocki, G.; Valgimigli, L.; Amorati, R.; Ferroni, F.; Demailly-Mullie, C.; Siriwardena, A.; Lesur, D.; Aubry, F.; Demailly, G.
Tetrahedron 2015, 71, 5602-5609.
We report a newly developed synthesis of a no. of alditol thiacrowns using an eco-friendly and versatile two-step strategy: the regioselective thioallyletherification of a polyhydroxylated alditol followed by a ring closing metathesis using the Grubbs second generation catalyst. This approach allows a series of target thiacrown products to be obtained in acceptable to good yields, from the corresponding α,ω-dithioallylether alditol starting materials featuring either the xylo, ribo, threo, erythro, D-manno or D-gluco configurations. The per-O-acetylated D-mannitol dithioallyether 10, easily obtained on a large scale using this approach, was selected for evaluation as both an antibacterial and an antioxidant. Although no antibacterial activity was obsd. for the bacterial strains investigated, compd. 10 is shown to be an antioxidant, and able to quench hydrogen peroxide in a stoichiometric fashion.
http://dx.doi.org/10.1016/j.tet.2015.06.049


The synthesis of a glucoconjugate of the peptidic fragment of cryptophycin-24
Mezrai, A.; Lesur, D.; Wadouachi, A.; Pilard, F.; Mulengi, J. K.
Mediterranean Journal of Chemistry 2014, 3, 935-946.
A novel glucoconjugate of the peptidic fragment of cryptophycin-24 was prepd. through the replacement of the leucic acid residue with L-leucine and the functionalisation of tyrosine residue with glucose. Those modifications lead to a novel protected tripeptide fragment of cryptophycin-24.
http://dx.doi.org/10.13171/mjc.3.4.2014.04.07.15


The Synthesis of an Aziridinyl Analogue of Unit A of Cryptophycin-1
Mezrai, A.; Drici, W.; Lesur, D.; Mulengi, J.; Wadouachi, A.; Pilard, F.
Lett. Org. Chem. 2014, 11, 259-267.
A novel analog of unit A of cryptophycin-1 was prepd. starting from com. trans-cinnamaldehyde. The modifications introduced into the new structure related to the replacement of the epoxide with an aziridine moiety, and the inclusion of the 1,3-enone moiety into an arom. ester frame through the synthesis of a key arom. ketone. Asymmetry was induced during the later steps of the synthetic pathway. The optical purity of compds. was monitored by chiral HPLC and polarimetric measurements.
http://dx.doi.org/10.2174/1570178611999140221163917