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Aucagne Vincent


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2016   Références trouvées : 6

Jacobsen M. T., Petersen M. E., Ye X., Galibert M., Lorimer G. H., Aucagne V. and Kay M. S.  (2016)

A Helping Hand to Overcome Solubility Challenges in Chemical Protein Synthesis

Journal of the American Chemical Society (2016) 138 (36) 11775-11782 - doi : 10.1021/jacs.6b05719
Although native chemical ligation (NCL) and related chemoselective ligation approaches provide an elegant method to stitch together unprotected peptides, the handling and purification of insoluble and aggregation-prone peptides and assembly intermediates create a bottleneck to routinely preparing large proteins by completely synthetic means. In this work, we introduce a new general tool, Fmoc-Ddae-OH, N-Fmoc-1-(4,4-dimethyl-2,6-dioxocyclo-hexylidene)-3-[2-(2-aminoethoxy)ethoxy]-propan-1-ol, a heterobifunctional traceless linker for temporarily attaching highly solubilizing peptide sequences (“helping hands”) onto insoluble peptides. This tool is implemented in three simple and nearly quantitative steps : (i) on-resin incorporation of the linker at a Lys residue ε-amine, (ii) Fmoc-SPPS elongation of a desired solubilizing sequence, and (iii) in-solution removal of the solubilizing sequence using mild aqueous hydrazine to cleave the Ddae linker after NCL-based assembly. Successful introduction and removal of a Lys6 helping hand is first demonstrated in two model systems (Ebola virus C20 peptide and the 70-residue ribosomal protein L31). It is then applied to the challenging chemical synthesis of the 97-residue co-chaperonin GroES, which contains a highly insoluble C-terminal segment that is rescued by a helping hand. Importantly, the Ddae linker can be cleaved in one pot following NCL or desulfurization. The purity, structure, and chaperone activity of synthetic l-GroES were validated with respect to a recombinant control. Additionally, the helping hand enabled synthesis of d-GroES, which was inactive in a heterochiral mixture with recombinant GroEL, providing additional insight into chaperone specificity. Ultimately, this simple, robust, and easy-to-use tool is expected to be broadly applicable for the synthesis of challenging peptides and proteins.

Although native chemical ligation (NCL) and related chemoselective ligation approaches provide an elegant method to stitch together unprotected peptides, the handling and purification of insoluble and aggregation-prone peptides and assembly intermediates create a bottleneck to routinely preparing large proteins by completely synthetic means. In this work, we introduce a new general tool, Fmoc-Ddae-OH, N-Fmoc-1-(4,4-dimethyl-2,6-dioxocyclo-hexylidene)-3-[2-(2-aminoethoxy)ethoxy]-propan-1-ol, a heterobifunctional traceless linker for temporarily attaching highly solubilizing peptide sequences (“helping hands”) onto insoluble peptides. This tool is implemented in three simple and nearly quantitative steps : (i) on-resin incorporation of the linker at a Lys residue ε-amine, (ii) Fmoc-SPPS elongation of a desired solubilizing sequence, and (iii) in-solution removal of the solubilizing sequence using mild aqueous hydrazine to cleave the Ddae linker after NCL-based assembly. Successful introduction and removal of a Lys6 helping hand is first demonstrated in two model systems (Ebola virus C20 peptide and the 70-residue ribosomal protein L31). It is then applied to the challenging chemical synthesis of the 97-residue co-chaperonin GroES, which contains a highly insoluble C-terminal segment that is rescued by a helping hand. Importantly, the Ddae linker can be cleaved in one pot following NCL or desulfurization. The purity, structure, and chaperone activity of synthetic l-GroES were validated with respect to a recombinant control. Additionally, the helping hand enabled synthesis of d-GroES, which was inactive in a heterochiral mixture with recombinant GroEL, providing additional insight into chaperone specificity. Ultimately, this simple, robust, and easy-to-use tool is expected to be broadly applicable for the synthesis of challenging peptides and proteins.

Gambade A., Zreika S., Guéguinou M., Chourpa I., Fromont-Hankard G., Bouchet A. M., Burlaud-Gaillard J., Potier-Cartereau M., Roger S., Aucagne V., Chevalier S., Vandier C., Goupille C. and Weber G.   (2016)

Activation of TRPV2 and BKCa channels by the LL-37 enantiomers stimulates calcium entry and migration of cancer cells

Oncotarget (2016) 7 (17) 23785-23800 - doi : 10.18632/oncotarget.8122
Expression of the antimicrobial peptide hCAP18/LL-37 is associated to malignancy in various cancer forms, stimulating cell migration and metastasis. We report that LL-37 induces migration of three cancer cell lines by activating the TRPV2 calcium-permeable channel and recruiting it to pseudopodia through activation of the PI3K/AKT pathway. Ca2+ entry through TRPV2 cooperated with a K+ efflux through the BKCa channel. In a panel of human breast tumors, the expression of TRPV2 and LL-37 was found to be positively correlated. The D-enantiomer of LL-37 showed identical effects as the L-peptide, suggesting that no binding to a specific receptor was involved. LL-37 attached to caveolae and pseudopodia membranes and decreased membrane fluidity, suggesting that a modification of the physical properties of the lipid membrane bilayer was the underlying mechanism of its effects.

Expression of the antimicrobial peptide hCAP18/LL-37 is associated to malignancy in various cancer forms, stimulating cell migration and metastasis. We report that LL-37 induces migration of three cancer cell lines by activating the TRPV2 calcium-permeable channel and recruiting it to pseudopodia through activation of the PI3K/AKT pathway. Ca2+ entry through TRPV2 cooperated with a K+ efflux through the BKCa channel. In a panel of human breast tumors, the expression of TRPV2 and LL-37 was found to be positively correlated. The D-enantiomer of LL-37 showed identical effects as the L-peptide, suggesting that no binding to a specific receptor was involved. LL-37 attached to caveolae and pseudopodia membranes and decreased membrane fluidity, suggesting that a modification of the physical properties of the lipid membrane bilayer was the underlying mechanism of its effects.

Decourt C., Robert V., Anger K., Galibert M., Madinier J. B., Liu X., Dardente H., Lomet D., Delmas A. F., Caraty A., Herbison A. E., Anderson G. M., Aucagne V. and Beltramo M.  (2016)

A synthetic kisspeptin analog that triggers ovulation and advances puberty

Scientific Reports (2016) 6, 26908 - doi : 10.1038/srep26908
The neuropeptide kisspeptin and its receptor, KiSS1R, govern the reproductive timeline of mammals by triggering puberty onset and promoting ovulation by stimulating gonadotrophin-releasing hormone (GnRH) secretion. To overcome the drawback of kisspeptin short half-life we designed kisspeptin analogs combining original modifications, triazole peptidomimetic and albumin binding motif, to reduce proteolytic degradation and to slow down renal clearance, respectively. These analogs showed improved in vitro potency and dramatically enhanced pharmacodynamics. When injected intramuscularly into ewes (15 nmol/ewe) primed with a progestogen, the best analog (compound 6, C6) induced synchronized ovulations in both breeding and non-breeding seasons. Ovulations were fertile as demonstrated by the delivery of lambs at term. C6 was also fully active in both female and male mice but was completely inactive in KiSS1R KO mice. Electrophysiological recordings of GnRH neurons from brain slices of GnRH-GFP mice indicated that C6 exerted a direct excitatory action on GnRH neurons. Finally, in prepubertal female mice daily injections (0.3 nmol/mouse) for five days significantly advanced puberty. C6 ability to trigger ovulation and advance puberty demonstrates that kisspeptin analogs may find application in the management of livestock reproduction and opens new possibilities for the treatment of reproductive disorders in humans.

The neuropeptide kisspeptin and its receptor, KiSS1R, govern the reproductive timeline of mammals by triggering puberty onset and promoting ovulation by stimulating gonadotrophin-releasing hormone (GnRH) secretion. To overcome the drawback of kisspeptin short half-life we designed kisspeptin analogs combining original modifications, triazole peptidomimetic and albumin binding motif, to reduce proteolytic degradation and to slow down renal clearance, respectively. These analogs showed improved in vitro potency and dramatically enhanced pharmacodynamics. When injected intramuscularly into ewes (15 nmol/ewe) primed with a progestogen, the best analog (compound 6, C6) induced synchronized ovulations in both breeding and non-breeding seasons. Ovulations were fertile as demonstrated by the delivery of lambs at term. C6 was also fully active in both female and male mice but was completely inactive in KiSS1R KO mice. Electrophysiological recordings of GnRH neurons from brain slices of GnRH-GFP mice indicated that C6 exerted a direct excitatory action on GnRH neurons. Finally, in prepubertal female mice daily injections (0.3 nmol/mouse) for five days significantly advanced puberty. C6 ability to trigger ovulation and advance puberty demonstrates that kisspeptin analogs may find application in the management of livestock reproduction and opens new possibilities for the treatment of reproductive disorders in humans.

Terrier V. P., Adihou H., Arnould M., Delmas A. F. and Aucagne V.  (2016)

A straightforward method for automated Fmoc-based synthesis of bio-inspired peptide crypto-thioesters

Chemical Science (2016) 7 (1) 339-345 - doi : 10.1039/C5SC02630J
Despite recent advances, the direct Fmoc-based solid phase synthesis of peptide [small alpha]-thioesters for the convergent synthesis of proteins via native chemical ligation (NCL) remains a challenge in the field. We herein report a simple and general methodology, enabling access to peptide thioester surrogates. A novel C-terminal N-(2-hydroxybenzyl)cysteine thioesterification device based on an amide-to-thioester rearrangement was developed, and the resulting peptide crypto-thioesters can be directly used in NCL reactions with fast N [rightward arrow] S shift kinetics at neutral pH. These fast kinetics arise from our bio-inspired design, via intein-like intramolecular catalysis. Due to a well-positioned phenol moiety, an impressive >50 fold increase in the kinetic rate is observed compared to an O-methylated derivative. Importantly, the synthesis of this new device can be fully automated using inexpensive commercially available materials and does not require any post-synthetic steps prior to NCL. We successfully applied this new method to the synthesis of two long naturally-occurring cysteine-rich peptide sequences.

Despite recent advances, the direct Fmoc-based solid phase synthesis of peptide [small alpha]-thioesters for the convergent synthesis of proteins via native chemical ligation (NCL) remains a challenge in the field. We herein report a simple and general methodology, enabling access to peptide thioester surrogates. A novel C-terminal N-(2-hydroxybenzyl)cysteine thioesterification device based on an amide-to-thioester rearrangement was developed, and the resulting peptide crypto-thioesters can be directly used in NCL reactions with fast N [rightward arrow] S shift kinetics at neutral pH. These fast kinetics arise from our bio-inspired design, via intein-like intramolecular catalysis. Due to a well-positioned phenol moiety, an impressive >50 fold increase in the kinetic rate is observed compared to an O-methylated derivative. Importantly, the synthesis of this new device can be fully automated using inexpensive commercially available materials and does not require any post-synthetic steps prior to NCL. We successfully applied this new method to the synthesis of two long naturally-occurring cysteine-rich peptide sequences.

Loth K., Alami S. A. I., Habès C., Garrido S., Aucagne V., Delmas A.F., Moreau, T., Zani M.-L. and Landon C.  (2016)

Complete 1H, 15N and 13C assignment of trappin-2 and 1H assignment of its two domains, elafin and cementoin

Biomolecular NMR Assignments (2016) 10 (1) 223-226 - doi : 10.1007/s12104-016-9671-1
Trappin-2 is a serine protease inhibitor with a very narrow inhibitory spectrum and has significant anti-microbial activities. It is a 10 kDa cationic protein composed of two distinct domains. The N-terminal domain (38 residues) named cementoin is known to be intrinsically disordered when it is not linked to the elafin. The C-terminal domain (57 residues), corresponding to elafin, is a cysteine-rich domain stabilized by four disulfide bridges and is characterized by a flat core and a flexible N-terminal part. To our knowledge, there is no structural data available on trappin-2. We report here the complete 1H, 15N and 13C resonance assignment of the recombinant trappin-2 and the 1H assignments of cementoin and elafin, under the same experimental conditions. This is the first step towards the 3D structure determination of the trappin-2.

Trappin-2 is a serine protease inhibitor with a very narrow inhibitory spectrum and has significant anti-microbial activities. It is a 10 kDa cationic protein composed of two distinct domains. The N-terminal domain (38 residues) named cementoin is known to be intrinsically disordered when it is not linked to the elafin. The C-terminal domain (57 residues), corresponding to elafin, is a cysteine-rich domain stabilized by four disulfide bridges and is characterized by a flat core and a flexible N-terminal part. To our knowledge, there is no structural data available on trappin-2. We report here the complete 1H, 15N and 13C resonance assignment of the recombinant trappin-2 and the 1H assignments of cementoin and elafin, under the same experimental conditions. This is the first step towards the 3D structure determination of the trappin-2.

Lelievre D., Terrier V. P., Delmas A. F. and Aucagne V.  (2016)

Native Chemical Ligation Strategy to Overcome Side Reactions during Fmoc-Based Synthesis of C-Terminal Cysteine-Containing Peptides

Organic letters (2016 18 (5) 920-923 - doi : 10.1021/acs.orglett.5b03612
The Fmoc-based solid phase synthesis of C-terminal cysteine-containing peptides is problematic, due to side reactions provoked by the pronounced acidity of the Calpha proton of cysteine esters. We herein describe a general strategy consisting of the postsynthetic introduction of the C-terminal Cys through a key chemoselective native chemical ligation reaction with N-Hnb-Cys peptide crypto-thioesters. This method was successfully applied to the demanding peptide sequences of two natural products of biological interest, giving remarkably high overall yields compared to that of a state of the art strategy.

The Fmoc-based solid phase synthesis of C-terminal cysteine-containing peptides is problematic, due to side reactions provoked by the pronounced acidity of the Calpha proton of cysteine esters. We herein describe a general strategy consisting of the postsynthetic introduction of the C-terminal Cys through a key chemoselective native chemical ligation reaction with N-Hnb-Cys peptide crypto-thioesters. This method was successfully applied to the demanding peptide sequences of two natural products of biological interest, giving remarkably high overall yields compared to that of a state of the art strategy.


2015   Références trouvées : 3

Beltramo, M., Robert, V., Galibert, M., Madinier, J.-B., Marceau, P., Dardente, H., Decourt, C., De Roux, N., Lomet, D., Delmas, A. F., Caraty, A. and Aucagne, V.  (2015)

Rational Design of Triazololipopeptides Analogs of Kisspeptin Inducing a Long-Lasting Increase of Gonadotropins

Journal of Medicinal Chemistry (2015) 58 (8) 3459-3470 - doi : 10.1021/jm5019675
New potent and selective KISS1R agonists were designed using a combination of rational chemical modifications of the endogenous neuropeptide kisspeptin 10 (KP10). Improved resistance to degradation and presumably reduced renal clearance were obtained by introducing a 1,4-disubstituted 1,2,3-triazole as a proteolysis-resistant amide mimic and a serum albumin-binding motif, respectively. These triazololipopeptides are highly potent full agonists of KISS1R and are >100 selective over the closely related NPFF1R. When injected in ewes with a quiescent reproductive system, the best compound of our series induced a much prolonged increase of luteinizing hormone release compared to KP10 and increased follicle-stimulating hormone plasma concentration. Hence, this KISS1R agonist is a new valuable pharmacological tool to explore the potential of KP system in reproduction control. Furthermore, it represents the first step to develop drugs treating reproductive system disorders due to a reduced activity of the hypothalamo–pituitary–gonadal axis such as delayed puberty, hypothalamic amenorrhea, and hypogonadotropic hypogonadism.

New potent and selective KISS1R agonists were designed using a combination of rational chemical modifications of the endogenous neuropeptide kisspeptin 10 (KP10). Improved resistance to degradation and presumably reduced renal clearance were obtained by introducing a 1,4-disubstituted 1,2,3-triazole as a proteolysis-resistant amide mimic and a serum albumin-binding motif, respectively. These triazololipopeptides are highly potent full agonists of KISS1R and are >100 selective over the closely related NPFF1R. When injected in ewes with a quiescent reproductive system, the best compound of our series induced a much prolonged increase of luteinizing hormone release compared to KP10 and increased follicle-stimulating hormone plasma concentration. Hence, this KISS1R agonist is a new valuable pharmacological tool to explore the potential of KP system in reproduction control. Furthermore, it represents the first step to develop drugs treating reproductive system disorders due to a reduced activity of the hypothalamo–pituitary–gonadal axis such as delayed puberty, hypothalamic amenorrhea, and hypogonadotropic hypogonadism.

Galibert M., Piller V., Piller F., Aucagne V., Delmas A.F.  (2015)

Combining solid phase chemical ligations and enzymatic glycosylations for the synthesis of glycoproteins

Chemical Science (2015) 6 (6) 3617-3623 - doi : 10.1039/C5SC00773A
The solid-phase chemical assembly of a protein through iterative chemoselective ligation of unprotected peptide segments can be followed with chemical and/or enzymatic transformations of the resulting immobilized protein, the latter steps thus benefitting from the advantages provided by the solid support. We demonstrate here the usefulness of this strategy for the chemo-enzymatic synthesis of glycoprotein analogues. A linker was specifically designed for application to the synthesis of O-glycoproteins : this new linker is readily cleaved under mild aqueous conditions compatible with very sensitive glycosidic bonds, but is remarkably stable under a wide range of chemical and biochemical conditions. It was utilized for solid-supported N-to-C peptidomimetic triazole ligation followed by enzymatic glycosylation, ultimately leading to a very large MUC1-derived glycoprotein containing 160 amino acid residues, 24 α-GalNAc moieties linked to Ser and Thr, and 3 triazoles as peptide bond mimetics.

The solid-phase chemical assembly of a protein through iterative chemoselective ligation of unprotected peptide segments can be followed with chemical and/or enzymatic transformations of the resulting immobilized protein, the latter steps thus benefitting from the advantages provided by the solid support. We demonstrate here the usefulness of this strategy for the chemo-enzymatic synthesis of glycoprotein analogues. A linker was specifically designed for application to the synthesis of O-glycoproteins : this new linker is readily cleaved under mild aqueous conditions compatible with very sensitive glycosidic bonds, but is remarkably stable under a wide range of chemical and biochemical conditions. It was utilized for solid-supported N-to-C peptidomimetic triazole ligation followed by enzymatic glycosylation, ultimately leading to a very large MUC1-derived glycoprotein containing 160 amino acid residues, 24 α-GalNAc moieties linked to Ser and Thr, and 3 triazoles as peptide bond mimetics.

Barat, R., Legigan, T., Tranoy-Opalinski, I., Renoux, B., Peraudeau, E., Clarhaut, J., Poinot, P., Fernandes, A. E., Aucagne, V., Leigh, David A. and Papot, S.  (2015)

A mechanically interlocked molecular system programmed for the delivery of an anticancer drug

Chemical Science (2015) 6 (4) 2608-2613 - doi : 10.1039/C5SC00648A
The development of mechanically interlocked molecular systems programmed to operate autonomously in biological environments is an emerging field of research with potential medicinal applications. Within this framework, functional rotaxane- and pseudorotaxane-based architectures are starting to attract interest for the delivery of anticancer drugs, with the ultimate goal to improve the efficiency of cancer chemotherapy. Here, we report an enzyme-sensitive [2]-rotaxane designed to release a potent anticancer drug within tumor cells. The molecular device includes a protective ring that prevents the premature liberation of the drug in plasma. However, once located inside cancer cells the [2]-rotaxane leads to the release of the drug through the controlled disassembly of the mechanically interlocked components, in response to a determined sequence of two distinct enzymatic activations. Furthermore, in vitro biological evaluations reveal that this biocompatible functional system exhibits a noticeable level of selectivity for cancer cells overexpressing [small beta]-galactosidase.

The development of mechanically interlocked molecular systems programmed to operate autonomously in biological environments is an emerging field of research with potential medicinal applications. Within this framework, functional rotaxane- and pseudorotaxane-based architectures are starting to attract interest for the delivery of anticancer drugs, with the ultimate goal to improve the efficiency of cancer chemotherapy. Here, we report an enzyme-sensitive [2]-rotaxane designed to release a potent anticancer drug within tumor cells. The molecular device includes a protective ring that prevents the premature liberation of the drug in plasma. However, once located inside cancer cells the [2]-rotaxane leads to the release of the drug through the controlled disassembly of the mechanically interlocked components, in response to a determined sequence of two distinct enzymatic activations. Furthermore, in vitro biological evaluations reveal that this biocompatible functional system exhibits a noticeable level of selectivity for cancer cells overexpressing [small beta]-galactosidase.


2014   Références trouvées : 2

Meindre, F., Lelièvre, D., Loth, K., Mith, O., Aucagne, V., Berthomieu, P., Marquès, L., Delmas, A. F., Landon, C. and Paquet, F.  (2014)

The Nuclear Magnetic Resonance Solution Structure of the Synthetic AhPDF1.1b Plant Defensin Evidences the Structural Feature within the γ-Motif

Biochemistry (2014) 53 (49) 7745-7754 - doi : 10.1021/bi501285k
Plant defensins (PDF) are cysteine-rich peptides that are major actors in the innate immunity in plants. Besides their antifungal activity, some PDF such as Arabidopsis halleri PDF1.1b confer zinc tolerance in plants. Here we present (i) an efficient protocol for the production of AhPDF1.1b by solid-phase peptide synthesis followed by controlled oxidative folding to obtain the highly pure native form of the defensin and (ii) the three-dimensional (3D) nuclear magnetic resonance structure of AhPDF1.1b, the first 3D structure of plant defensin obtained with a synthetic peptide. Its fold is organized around the typical cysteine-stabilized α-helix ?-sheet motif and contains the ?-core motif involved in the antifungal activity of all plant defensins. On the basis of our structural analysis of AhPDF1 defensins combined with previous biological data for antifungal and zinc tolerance activities, we established the essential role of cis-Pro41 within the ?-core. In fact, the four consecutive residues (Val39-Phe40-Pro41-Ala42) are strictly conserved for plant defensins able to tolerate zinc. We hypothesized that structural and/or dynamic features of this sequence are related to the ability of the defensin to chelate zinc.

Plant defensins (PDF) are cysteine-rich peptides that are major actors in the innate immunity in plants. Besides their antifungal activity, some PDF such as Arabidopsis halleri PDF1.1b confer zinc tolerance in plants. Here we present (i) an efficient protocol for the production of AhPDF1.1b by solid-phase peptide synthesis followed by controlled oxidative folding to obtain the highly pure native form of the defensin and (ii) the three-dimensional (3D) nuclear magnetic resonance structure of AhPDF1.1b, the first 3D structure of plant defensin obtained with a synthetic peptide. Its fold is organized around the typical cysteine-stabilized α-helix ?-sheet motif and contains the ?-core motif involved in the antifungal activity of all plant defensins. On the basis of our structural analysis of AhPDF1 defensins combined with previous biological data for antifungal and zinc tolerance activities, we established the essential role of cis-Pro41 within the ?-core. In fact, the four consecutive residues (Val39-Phe40-Pro41-Ala42) are strictly conserved for plant defensins able to tolerate zinc. We hypothesized that structural and/or dynamic features of this sequence are related to the ability of the defensin to chelate zinc.

Decostaire, I.E., Lelievre, D., Aucagne, V. and Delmas, A.F.  (2014)

Solid phase oxime ligations for the iterative synthesis of polypeptide conjugates

Organic & Biomolecular Chemistry (2014) 12 (29) 5536-5543 - doi : 10.1039/c4ob00760c
Peptide-based complex biomacromolecules are now optimally assembled by sequential ligation of unprotected peptide segments. However, this approach is still limited by the laborious chromatographic purification and handling steps needed for multiple successive chemoselective couplings, which leads to loss of material. An efficient alternative is solid phase chemical ligation (SPCL) initially developed for native chemical ligation. We report here an extension of this approach to iterative oxime ligation reactions, and describe a streamlined approach for the modular preparation of oxime-containing polypeptides. In particular, we determined optimal conditions to remove the Aloc group in the presence of aminooxy and oxime ether groups, and we extended the applicability of iterative C-to-N SPCL through simplification of the access to a C-terminally-grafted, unprotected peptide segment, using solid supported chemical transformations only. The high purity of the crude oxime-containing polypeptides highlights the efficiency of our approach.

Peptide-based complex biomacromolecules are now optimally assembled by sequential ligation of unprotected peptide segments. However, this approach is still limited by the laborious chromatographic purification and handling steps needed for multiple successive chemoselective couplings, which leads to loss of material. An efficient alternative is solid phase chemical ligation (SPCL) initially developed for native chemical ligation. We report here an extension of this approach to iterative oxime ligation reactions, and describe a streamlined approach for the modular preparation of oxime-containing polypeptides. In particular, we determined optimal conditions to remove the Aloc group in the presence of aminooxy and oxime ether groups, and we extended the applicability of iterative C-to-N SPCL through simplification of the access to a C-terminally-grafted, unprotected peptide segment, using solid supported chemical transformations only. The high purity of the crude oxime-containing polypeptides highlights the efficiency of our approach.


2013   Références trouvées : 1

Raibaut, L., Adihou, H., Desmet, R., Delmas, A.F., Aucagne and V. Melnyk, O.  (2013)

Highly efficient solid phase synthesis of large polypeptides by iterative ligations of bis(2-sulfanylethyl)amido (SEA) peptide segments

Chemical Science 4 (10) 4061-4066
Up to now, the advantages of solid phase protein synthesis have been largely under-utilized due to the difficulty of designing a simple and efficient elongation cycle enabling the concatenation of unprotected peptide segments. The combination of selective N-terminal anchoring (N3-Esoc linker) with the blocked thioester properties of the SEAoff group enabled the solid phase concatenation of unprotected peptide segments by N-to-C sequential formation of native peptide bonds. The strategy was applied to the synthesis of a 60 amino acid-long latent peptide thioester or to the assembly of five peptide segments to give a 15 kDa polypeptide.

Up to now, the advantages of solid phase protein synthesis have been largely under-utilized due to the difficulty of designing a simple and efficient elongation cycle enabling the concatenation of unprotected peptide segments. The combination of selective N-terminal anchoring (N3-Esoc linker) with the blocked thioester properties of the SEAoff group enabled the solid phase concatenation of unprotected peptide segments by N-to-C sequential formation of native peptide bonds. The strategy was applied to the synthesis of a 60 amino acid-long latent peptide thioester or to the assembly of five peptide segments to give a 15 kDa polypeptide.


2012   Références trouvées : 5

Aucagne, V., Valverde, I.E., Marceau, P., Galibert, M., Dendane, N., Delmas, A.F.  (2012)

Towards the Simplification of Protein Synthesis : Iterative Solid-Supported Ligations with Concomitant Purifications

Angewandte Chemie International Edition, 51 (45) 11320-11324
Please release me : A new linker for the temporary tagging of peptides at their N-terminus after solid-phase elongation, and its potential for capture/release purification is demonstrated. This concept is extended to a remarkably efficient self-purifying N-to-C iterative triazole ligation strategy, which is applied to the synthesis of a polypeptide having 160 residues, in a high purity without the need for chromatographic purification (see picture ; orange blocks : peptide segments).

Please release me : A new linker for the temporary tagging of peptides at their N-terminus after solid-phase elongation, and its potential for capture/release purification is demonstrated. This concept is extended to a remarkably efficient self-purifying N-to-C iterative triazole ligation strategy, which is applied to the synthesis of a polypeptide having 160 residues, in a high purity without the need for chromatographic purification (see picture ; orange blocks : peptide segments).

Gaulier, C., Hospital, A., Legeret, B., Delmas, A.F., Aucagne, V., Cisnetti, F. and Gautier, A.  (2012)

A Water Soluble CuI–NHC for CuAAC ligation of unprotected peptides under open air conditions

Chemical Communications 48 (33) 4005-4007
A reducing agent–free version of CuAAC able to operate

under open air conditions is reported. A readily–synthesizable, hydrophilic and highly stable CuI–NHC allows the clean ligations of unprotected peptides comprising sensitive side chains, at millimolar concentrations.

A reducing agent–free version of CuAAC able to operate
under open air conditions is reported. A readily–synthesizable, hydrophilic and highly stable CuI–NHC allows the clean ligations of unprotected peptides comprising sensitive side chains, at millimolar concentrations.

Derache, C., Meudal, H., Aucagne, V., Mark, K.J., Cadène, M., Delmas, A.F., Lalmanach, A.C. and Landon, C.  (2012)

Initial insights into the structure-activity relationships of avian defensins

Journal of Biological Chemistry 287 (10) 7746-7755
Numerous β-defensins have been identified in birds and the potential use of these peptides as alternatives to antibiotics has been proposed, in particular to fight antibiotic-resistant and zoonotic bacterial species. Little is known about the mechanism of antibacterial activity of avian β-defensins (AvBDs), and the present work was carried out to obtain initial insights into the involvement of structural features or specific residues in the antimicrobial activity of chicken AvBD2. Chicken AvBD2 and its enantiomeric counterpart were chemically synthesized. Peptide elongation and oxidative folding were both optimized. The similar antimicrobial activity measured for both L- and D- proteins clearly indicates that there is no chiral partner. Therefore the bacterial membrane is in all likelihood the primary target. Moreover, this work evidences that the three-dimensional fold is required for an optimal antimicrobial activity, in particular for Gram-positive bacterial strains. The three-dimensional NMR structure of chicken AvBD2 defensin displays the structural 3-stranded antiparallel β-sheet characteristic of β-defensins. The surface of the molecule does not display any amphipathic character. In light of this new structure and of the king penguin AvBD103b defensin structure, the consensus sequence of avian β-defensin′s family was analyzed. Well conserved residues were highlighted and the potential strategic role of the lysine 31 residue of AvBD2 emphasized. The synthetic AvBD2-K31A variant displayed substantial N-terminal structural modifications and a dramatic decrease in activity. Taken together, these results demonstrate the structural as well as the functional role of the critical lysine 31 residue in antimicrobial activity.

Numerous β-defensins have been identified in birds and the potential use of these peptides as alternatives to antibiotics has been proposed, in particular to fight antibiotic-resistant and zoonotic bacterial species. Little is known about the mechanism of antibacterial activity of avian β-defensins (AvBDs), and the present work was carried out to obtain initial insights into the involvement of structural features or specific residues in the antimicrobial activity of chicken AvBD2. Chicken AvBD2 and its enantiomeric counterpart were chemically synthesized. Peptide elongation and oxidative folding were both optimized. The similar antimicrobial activity measured for both L- and D- proteins clearly indicates that there is no chiral partner. Therefore the bacterial membrane is in all likelihood the primary target. Moreover, this work evidences that the three-dimensional fold is required for an optimal antimicrobial activity, in particular for Gram-positive bacterial strains. The three-dimensional NMR structure of chicken AvBD2 defensin displays the structural 3-stranded antiparallel β-sheet characteristic of β-defensins. The surface of the molecule does not display any amphipathic character. In light of this new structure and of the king penguin AvBD103b defensin structure, the consensus sequence of avian β-defensin′s family was analyzed. Well conserved residues were highlighted and the potential strategic role of the lysine 31 residue of AvBD2 emphasized. The synthetic AvBD2-K31A variant displayed substantial N-terminal structural modifications and a dramatic decrease in activity. Taken together, these results demonstrate the structural as well as the functional role of the critical lysine 31 residue in antimicrobial activity.

Fernandes, A., Viterisi, A., Aucagne, V., Leigh, D.A. and Papot, S.  (2012)

Second generation specific-enzyme-activated rotaxane propeptides

Chemical Communications 48 (15) 2083-2085
A [2]rotaxane, in which the peptidic axle is protected from degradation by the macrocyclic sheath and terminated with a novel glycosidase-cleavable stopper, is rendered water-soluble by derivatisation with tetra(ethylene glycol) (TetEG) or glucosylated tetra(ethylene glycol) (Glc-TetEG) chains using the CuAAC 'click' reaction. The Glc-TetEG-derivatised rotaxane propeptide is >50 000 times more soluble in aqueous media than the parent rotaxane. Activation of the water-soluble rotaxane propeptide with a β-galactosidase efficiently releases the parent peptide.

A [2]rotaxane, in which the peptidic axle is protected from degradation by the macrocyclic sheath and terminated with a novel glycosidase-cleavable stopper, is rendered water-soluble by derivatisation with tetra(ethylene glycol) (TetEG) or glucosylated tetra(ethylene glycol) (Glc-TetEG) chains using the CuAAC ’click’ reaction. The Glc-TetEG-derivatised rotaxane propeptide is >50 000 times more soluble in aqueous media than the parent rotaxane. Activation of the water-soluble rotaxane propeptide with a β-galactosidase efficiently releases the parent peptide.

Valverde, I., Lecaille, F., Lalmanach, G., Aucagne, V. & Delmas, A.F.  (2012)

Synthesis of a biologically active triazole-containing analogue of cystatin A through successive peptidomimetic alkyne–azide ligations

Angewandte Chemie International Edition 51 (3) 718-722
“Click” protein : CuI-catalyzed cycloaddition of azides and terminal alkynes has been applied to the successive ligations of three unprotected peptide fragments. Peptidomimetic triazole ligation (PTL, see scheme) as a new method for the chemical production of bioactive proteins is applied for the synthesis of a triazole-containing analogue of the 97 amino acid protein cystatin A.

“Click” protein : CuI-catalyzed cycloaddition of azides and terminal alkynes has been applied to the successive ligations of three unprotected peptide fragments. Peptidomimetic triazole ligation (PTL, see scheme) as a new method for the chemical production of bioactive proteins is applied for the synthesis of a triazole-containing analogue of the 97 amino acid protein cystatin A.


2010   Références trouvées : 1

Aucagne, V.  (2010)

(9H-Fluoren-9-yl)methanethiol

In "e-EROS Encyclopedia of Reagents for Organic Synthesis" (2010) - doi : 10.1002/047084289X.rn01287
[957753-00-3] C14H12S (MW 212.32)

InChI = 1S/C14H12S/c15-9-14-12-7-3-1-5-10(12)11-6-2-4-8-13(11)14/h1-8,14-15H,9H2

InChIKey = MXHVORUHWLKKMZ-UHFFFAOYSA-N

(reagent used to introduce a masked thiocarboxylic acid through thioesterification)

Alternate Name : Fm SH.

Physical Data : no reported physical data other than NMR and MS.

Solubility : soluble in Et2O, CH2Cl2, and other common organic solvents ; insoluble in water.

Form Supplied in : pale yellow oil.

Analysis of Reagent Purity : 1H and 13C NMR.

Preparative Method : not yet commercially available. FmSH can be prepared in three steps from commercially available (9H-fluoren-9-yl)methanol (FmOH) by treatment with tosyl chloride and pyridine in chloroform at rt for 6 h,1 followed by displacement of the tosylate by potassium thioacetate and 18-crown-6 in DMF at rt for 2 h, and then reduction with DIBAL-H in Et2O at –78 °C and then at 0 °C for 30 min.2 Purification requires column chromatography.

Purification : flash column chromatography on silica gel : 98:2 hexane/ethyl acetate.

Handling, Storage, and Precautions : stable under normal pressure and temperature in the absence of air. Unpleasant odor. Store in a cool dry place under an inert atmosphere. Wash thoroughly after use and remove any contaminated clothing. The toxicological properties have not been studied.

[957753-00-3] C14H12S (MW 212.32)
InChI = 1S/C14H12S/c15-9-14-12-7-3-1-5-10(12)11-6-2-4-8-13(11)14/h1-8,14-15H,9H2
InChIKey = MXHVORUHWLKKMZ-UHFFFAOYSA-N
(reagent used to introduce a masked thiocarboxylic acid through thioesterification)
Alternate Name : Fm SH.
Physical Data : no reported physical data other than NMR and MS.
Solubility : soluble in Et2O, CH2Cl2, and other common organic solvents ; insoluble in water.
Form Supplied in : pale yellow oil.
Analysis of Reagent Purity : 1H and 13C NMR.
Preparative Method : not yet commercially available. FmSH can be prepared in three steps from commercially available (9H-fluoren-9-yl)methanol (FmOH) by treatment with tosyl chloride and pyridine in chloroform at rt for 6 h,1 followed by displacement of the tosylate by potassium thioacetate and 18-crown-6 in DMF at rt for 2 h, and then reduction with DIBAL-H in Et2O at –78 °C and then at 0 °C for 30 min.2 Purification requires column chromatography.
Purification : flash column chromatography on silica gel : 98:2 hexane/ethyl acetate.
Handling, Storage, and Precautions : stable under normal pressure and temperature in the absence of air. Unpleasant odor. Store in a cool dry place under an inert atmosphere. Wash thoroughly after use and remove any contaminated clothing. The toxicological properties have not been studied.


2009   Références trouvées : 3

Valverde, I.E., Delmas, A.F. & Aucagne, V.  (2009)

Click a la carte : robust semi-orthogonal alkyne protecting groups for multiple successive azide/alkyne cycloadditions.

Tetrahedron 65, 7597-7602.

Fernandes, A., Viterisi, A., Coutrot, F., Potok, S., Leigh, D.A., Aucagne, V. & Papot, S.  (2009)

Rotaxane-Based Propeptides : Protection and Enzymatic Release of a Bioactive Pentapeptide.

Angew. Chem. Int. Edit. 48, 6443-6447.

Derache, C., Labas, V., Aucagne, V., Meudal, H., Landon, C., Delmas, A.F., Magallon, T. & Lalmanach, A.C.  (2009)

Primary Structure and Antibacterial Activity of Chicken Bone Marrow-Derived beta-Defensins.

Antimicrob. Agents Chemother. 53, 4647-4655.


2008   Références trouvées : 2

Aucagne, V., Tatibouet, A. & Rollin, P.  (2008)

Thermodynamics versus kinetics in hetero-Michael cyclizations : a highly stereoselective approach to access both epimers of a C-D-mannopyranoside.

Tetrahedron Lett. 49, 4750-4753.

Lelièvre, D ; Barta, P ; Aucagne, V ; Delmas, AF  (2008)

Preparation of peptide thioesters using Fmoc strategy through hydroxyl side chain anchoring

Tetrahedron Letters 49 4016-4019


2007   Références trouvées : 4

Decostaire, IP ; Lelièvre, D ; Aucagne, V ; Delmas, AF  (2007)

Synergic effect of hydride and proton donors in the Pd(0)-mediated deprotection of N-a-Aloc proline derivatives

Tetrahedron Letters 48 6523-6526
In this study, the challenging Pd(O)-catalyzed N-Aloc removal from a proline residue using Me2NH-BH3 or PhSiH3 as allyl scavengers has been investigated. Standard conditions led to a large amount of an allylamine byproduct. A careful study of the reactions allowed us to design the optimal conditions for the quick and quantitative formation of the desired product, while taking advantage of a synergic effect between hydride and proton donors. (c) 2007 Elsevier Ltd. All rights reserved.

In this study, the challenging Pd(O)-catalyzed N-Aloc removal from a proline residue using Me2NH-BH3 or PhSiH3 as allyl scavengers has been investigated. Standard conditions led to a large amount of an allylamine byproduct. A careful study of the reactions allowed us to design the optimal conditions for the quick and quantitative formation of the desired product, while taking advantage of a synergic effect between hydride and proton donors. (c) 2007 Elsevier Ltd. All rights reserved.

Broggi, J ; Joubert, N ; Aucagne, V ; Zevaco, T ; Berteina-Raboin, S ; Nolan, SR ; Agrofoglio, LA  (2007)

Study of different copper(I) catalysts for the "click chemistry" approach to carbanucleosides

Nucleosides Nucleotides & Nucleic Acids 26 779-783
We compare herein the scope of three copper (I) catalysts on the synthesis of various 1,4-disubstitued-1,2,3-triazolo-carbanucleosides through a microwave (and thermic) assisted Huisgen 1,3-dipolar cycloaddition. The tetrakis(acelonitrile)copper hexafluorophosphate ([Cu(CH3CN4]PF6), the imidazoline(mesythyl)copper bromide (Imes)CuBr, and the copper/copper sulfate Cu(0)/CuSO4 (II) mixture have been chosen for this study. Their influence in a catalytic amount will be analyzed according to the substituent of the alkyne, the solvent, or the heating method.

We compare herein the scope of three copper (I) catalysts on the synthesis of various 1,4-disubstitued-1,2,3-triazolo-carbanucleosides through a microwave (and thermic) assisted Huisgen 1,3-dipolar cycloaddition. The tetrakis(acelonitrile)copper hexafluorophosphate ([Cu(CH3CN4]PF6), the imidazoline(mesythyl)copper bromide (Imes)CuBr, and the copper/copper sulfate Cu(0)/CuSO4 (II) mixture have been chosen for this study. Their influence in a catalytic amount will be analyzed according to the substituent of the alkyne, the solvent, or the heating method.

Aucagne, V ; Berna, J ; Crowley, JD ; Goldup, SM ; Haenni, KD ; Leigh, DA ; Lusby, PJ ; Ronaldson, VE ; Slawin, AMZ ; Viterisi, A ; Walker, DB  (2007)

Catalytic "Active-Metal" template synthesis of [2]rotaxanes, [3]rotaxanes, and molecular shuttles, and some observations on the mechanism of the Cu(I)-catalyzed azide-alkyne 1,3-cycloaddition

Journal of The American Chemical Society 129 11950-11963
A synthetic approach to rotaxane architectures is described in which metal atoms catalyze covalent bond formation while simultaneously acting as the template for the assembly of the mechanically interlocked structure. This "active- metal" template strategy is exemplified using the Huisgen-Meldal-Fokin Cu(l)catalyzed 1,3-cycloaddition of azides with terminal alkynes (the CuAAC "click" reaction). Coordination of Cu(I) to an endotopic pyridine-containing macrocycle allows the alkyne and azide to bind to metal atoms in such a way that the metal-mediated bond-forming reaction takes place through the cavity of the macrocycle-or macrocycles-forming a rotaxane.

A synthetic approach to rotaxane architectures is described in which metal atoms catalyze covalent bond formation while simultaneously acting as the template for the assembly of the mechanically interlocked structure. This "active- metal" template strategy is exemplified using the Huisgen-Meldal-Fokin Cu(l)catalyzed 1,3-cycloaddition of azides with terminal alkynes (the CuAAC "click" reaction). Coordination of Cu(I) to an endotopic pyridine-containing macrocycle allows the alkyne and azide to bind to metal atoms in such a way that the metal-mediated bond-forming reaction takes place through the cavity of the macrocycle-or macrocycles-forming a rotaxane.

Broggi, J ; Joubert, N ; Aucagne, V ; Berteina-Raboin, S ; Diez-Gonzalez, S ; Nolan, S ; Topalis, D ; Deville-Bonne, D ; Balzarini, J ; Neyts, J ; Andrei, G ; Snoeck, R ; Agrofoglio, LA  (2007)

Alkyne-azide click chemistry mediated carbanucleosides synthesis

Nucleosides Nucleotides & Nucleic Acids 26 1391-1394
Hitherto unknown 1,4-disubstituted-[1,2,3]-triazolo-4',4'-dihydroxymethyl-3'-deoxycarbanucleosides were synthesized based on a "click approach." Various alkynes were introduced on a key azido intermediate by the "click" 1,3-dipolar Huisgen cycloaddition. Their antiviral activities and cellular toxicities were evaluated on vaccinia virus. None of the synthesized compounds exhibited a significant antiviral activity.

Hitherto unknown 1,4-disubstituted-[1,2,3]-triazolo-4’,4’-dihydroxymethyl-3’-deoxycarbanucleosides were synthesized based on a "click approach." Various alkynes were introduced on a key azido intermediate by the "click" 1,3-dipolar Huisgen cycloaddition. Their antiviral activities and cellular toxicities were evaluated on vaccinia virus. None of the synthesized compounds exhibited a significant antiviral activity.


2006   Références trouvées : 3

Aucagne, V ; Leigh, DA ; Lock, JS ; Thomson, AR  (2006)

Rotaxanes of cyclic peptides

Journal of The American Chemical Society 128 (6) 1784-1785

Aucagne, V ; Leigh, DA  (2006)

Chemoselective formation of successive triazole linkages in one pot : " Click-click" chemistry

Organic Letters 8 (20) 4505-4507
A methodology for the successive regiospecific "clicking" together of three components in one pot via two triazole linkages is reported. The protocol utilizes copper(I)-mediated alkyne-azide cycloaddition reactions combined with a silver(I)-catalyzed TMS-alkyne deprotection under mild hydroalcoholic conditions. We exemplify the approach with peptide-based components to illustrate its compatibility with polyfunctionalized biomolecules. The method constitutes a promising tool for peptide ligation. We also provide a procedure for directly using TMS-alkynes as the cycloaddition partner in classical "click" chemistry.

A methodology for the successive regiospecific "clicking" together of three components in one pot via two triazole linkages is reported. The protocol utilizes copper(I)-mediated alkyne-azide cycloaddition reactions combined with a silver(I)-catalyzed TMS-alkyne deprotection under mild hydroalcoholic conditions. We exemplify the approach with peptide-based components to illustrate its compatibility with polyfunctionalized biomolecules. The method constitutes a promising tool for peptide ligation. We also provide a procedure for directly using TMS-alkynes as the cycloaddition partner in classical "click" chemistry.

Aucagne, V ; Hanni, KD ; Leigh, DA ; Lusby, PJ ; Walker, DB  (2006)

Catalytic "click" rotaxanes : A substoichiometric metal-template pathway to mechanically interlocked architectures

Journal of The American Chemical Society 128 (7) 2186-2187


2005   Références trouvées : 3

Escuret, V ; Aucagne, V ; Joubert, N ; Durantel, D ; Rapp, KL ; Schinazi, RF ; Zoulim, F ; Agrofoglio, LA  (2005)

Synthesis of 5-haloethynyl- and 5-(1,2-dihalo)vinyluracil-nucleosides : Antiviral activity and cellular toxicity

Bioorganic & Medicinal Chemistry 13 (21) 6015-6024
In this article, we report the synthesis of hitherto unknown 5-haloethynyl and 5-(1,2-dihalo)vinyluracil nucleosides in the 2'-deoxy, 3'-deoxy- and ribosyl series, and we discuss their in vitro anti-HIV and anti-HCV activities and cellular toxicitites. As a result, on the basis of their selectivity index (SI) obtained with the HCV replicon system, but also on their cytotoxicity on peripheral blood mononuclear, CEM and VERO cell lines, the best compounds were the 5-bromoethynyluridine (SI = 3.2) and the 5-(1-chloro-2-iodo)vinyluridine (SI > 2.8). (c) 2005 Elsevier Ltd. All rights reserved.

In this article, we report the synthesis of hitherto unknown 5-haloethynyl and 5-(1,2-dihalo)vinyluracil nucleosides in the 2’-deoxy, 3’-deoxy- and ribosyl series, and we discuss their in vitro anti-HIV and anti-HCV activities and cellular toxicitites. As a result, on the basis of their selectivity index (SI) obtained with the HCV replicon system, but also on their cytotoxicity on peripheral blood mononuclear, CEM and VERO cell lines, the best compounds were the 5-bromoethynyluridine (SI = 3.2) and the 5-(1-chloro-2-iodo)vinyluridine (SI > 2.8). (c) 2005 Elsevier Ltd. All rights reserved.

Amblard, F ; Aucagne, V ; Guenot, P ; Schinazi, RF ; Agrofoglio, LA  (2005)

Synthesis and antiviral activity of novel acyclic nucleosides in the 5-alkynyl- and 6-alkylfuro[2,3-d]pyrimidine series

Bioorganic & Medicinal Chemistry 13 (4) 1239-1248
The synthesis of novel acyclic nucleosides in the 5-alkynyl and 6-alkylfuro[2,3-d]pyrimidine series is described. These compounds were evaluated against HIV and HSV in order to determine their spectrum of antiviral activity. Their cytotoxicities against PBM, CEM and VERO cells were also determined. Compounds 21d and 24b displayed moderate EC50S of 2.7 and 4.9 muM, respectively, against HIV-1 and of 6.3 and 4.8 muM, respectively, against HSV. Nevertheless, these compounds also showed cellular toxicity, suggesting that the antiviral effects are secondary to the toxic effects. (C) 2004 Elsevier Ltd. All rights reserved.

The synthesis of novel acyclic nucleosides in the 5-alkynyl and 6-alkylfuro[2,3-d]pyrimidine series is described. These compounds were evaluated against HIV and HSV in order to determine their spectrum of antiviral activity. Their cytotoxicities against PBM, CEM and VERO cells were also determined. Compounds 21d and 24b displayed moderate EC50S of 2.7 and 4.9 muM, respectively, against HIV-1 and of 6.3 and 4.8 muM, respectively, against HSV. Nevertheless, these compounds also showed cellular toxicity, suggesting that the antiviral effects are secondary to the toxic effects. (C) 2004 Elsevier Ltd. All rights reserved.

Aucagne, V ; Lorin, C ; Tatibouet, A ; Rollin, P  (2005)

Regioselective Michael-induced cyclisation of ?- and d-hydroxy vinyl sulfides and vinyl dithiocarbamates

Tetrahedron Letters 46 (25) 4349-4352
We herein describe the unprecedented use of heteroaryl vinyl sulfides and vinyl dithiocarbamates as hetero-Michael addition acceptors. Combined chelating and electron-withdrawing effects Lire Postulated to stabilise the transient anionic species and allow smooth Michael-induced ring closure to produce diversely functionalised C-glycosides. (c) 2005 Elsevier Ltd. All rights reserved.

We herein describe the unprecedented use of heteroaryl vinyl sulfides and vinyl dithiocarbamates as hetero-Michael addition acceptors. Combined chelating and electron-withdrawing effects Lire Postulated to stabilise the transient anionic species and allow smooth Michael-induced ring closure to produce diversely functionalised C-glycosides. (c) 2005 Elsevier Ltd. All rights reserved.


2004   Références trouvées : 3

Aucagne, V ; Tatibouet, A ; Rollin, P  (2004)

Wittig approach to carbohydrate-derived vinyl sulfides, new substrates for regiocontrolled ring-closure reactions

Tetrahedron 60 (8) 1817-1826
Reaction of methyl- and phenylthiomethylidene phosphoranes 1 and 2 with a variety of reducing sugars has been explored. Furano-type carbohydrates afforded with good yields the corresponding open-chain vinyl sulfides, whereas pyrano derivatives produced elimination compounds together with the expected vinyl sulfides, depending on the nature of the protective groups. (C) 2004 Elsevier Ltd. All rights reserved.

Reaction of methyl- and phenylthiomethylidene phosphoranes 1 and 2 with a variety of reducing sugars has been explored. Furano-type carbohydrates afforded with good yields the corresponding open-chain vinyl sulfides, whereas pyrano derivatives produced elimination compounds together with the expected vinyl sulfides, depending on the nature of the protective groups. (C) 2004 Elsevier Ltd. All rights reserved.

Aucagne, V ; Berteina-Raboin, S ; Guenot, P ; Agrofoglio, LA  (2004)

Palladium-catalyzed synthesis of uridines on polystyrene-based solid supports

Journal of Combinatorial Chemistry 6 (5) 717-723
In this paper, the solid-phase synthesis of various substituted pyrimidine nucleosides is described starting from 2'-deoxyuridine (1), which has been attached through a base labile linker 2 to polystyrene resins. The utility of the Pd(0) cross-coupling to functionalized pyrimidine nucleosides is expanded herein to include reactions of resin-supported 5-iodo-2'-deoxyuridine (8) under Sonogashira, Stille, Heck, and Suzuki conditions. Upon cleavage with MeONa, a library of 5-substituted pyrimidine nucleosides (10a-e, 11a-c, 12a-e) was obtained in good (under Sonogashira and Stille conditions) to moderate (under Heck or Suzuki conditions) yields and high purity. Except the Suzuki-type reactions, the presented methods exhibit a significant improvement and facilitate the synthetic procedure with respect to purification and yields (determined after filtration over silica gel).

In this paper, the solid-phase synthesis of various substituted pyrimidine nucleosides is described starting from 2’-deoxyuridine (1), which has been attached through a base labile linker 2 to polystyrene resins. The utility of the Pd(0) cross-coupling to functionalized pyrimidine nucleosides is expanded herein to include reactions of resin-supported 5-iodo-2’-deoxyuridine (8) under Sonogashira, Stille, Heck, and Suzuki conditions. Upon cleavage with MeONa, a library of 5-substituted pyrimidine nucleosides (10a-e, 11a-c, 12a-e) was obtained in good (under Sonogashira and Stille conditions) to moderate (under Heck or Suzuki conditions) yields and high purity. Except the Suzuki-type reactions, the presented methods exhibit a significant improvement and facilitate the synthetic procedure with respect to purification and yields (determined after filtration over silica gel).

Aucagne, V ; Amblard, F ; Agrofoglio, LA  (2004)

Highly efficient AgNO3-catalyzed preparation of substituted furanopyrimidine nucleosides

Synlett (13) 2406-2408
An efficient method for the synthesis of substituted furanopyrimidine nucleosides is described. Upon treatment with catalytic AgNO3, 5-alkynyl uracil derivatives were almost quantitatively converted into their corresponding bicyclic nucleoside analogues.

An efficient method for the synthesis of substituted furanopyrimidine nucleosides is described. Upon treatment with catalytic AgNO3, 5-alkynyl uracil derivatives were almost quantitatively converted into their corresponding bicyclic nucleoside analogues.


2003   Références trouvées : 1

Gillaizeau, I ; Lagoja, IM ; Nolan, SP ; Aucagne, V ; Rozenski, J ; Herdewijn, P ; Agrofoglio, LA  (2003)

Straightforward synthesis of labeled and unlabeled pyrimidine d4Ns via 2 ’,3 ’-diyne seco analogues through olefin metathesis reactions

European Journal of Organic Chemistry (4) 666-671
The synthesis of dideoxynucleosides (ddNs) or didehydro-dideoxynucleosides (d4Ns) from nucleosides has been extensively reviewed. While previously described methods are based on the modification of the 2'- and/or T-OH group of the intact ribose moiety, the use of a ring-closing metathesis (RCM) for the formation of the unsaturated cyclic system of nucleosides could be a straightforward approach to the d4Ns. Thus, as part of our drug labeling program, this paper reports a straightforward synthesis of 2',3'-didehydro-2',3'-dideoxyuridine (d4U) and [1',2',3',4',5'-C-13(5),6-C-13,1,3-N-15(2)]d4T using the RCM protocol. This paper discusses the preparation of nucleoside dienes and the activity of ruthenium-based metathesis catalysts. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).

The synthesis of dideoxynucleosides (ddNs) or didehydro-dideoxynucleosides (d4Ns) from nucleosides has been extensively reviewed. While previously described methods are based on the modification of the 2’- and/or T-OH group of the intact ribose moiety, the use of a ring-closing metathesis (RCM) for the formation of the unsaturated cyclic system of nucleosides could be a straightforward approach to the d4Ns. Thus, as part of our drug labeling program, this paper reports a straightforward synthesis of 2’,3’-didehydro-2’,3’-dideoxyuridine (d4U) and [1’,2’,3’,4’,5’-C-13(5),6-C-13,1,3-N-15(2)]d4T using the RCM protocol. This paper discusses the preparation of nucleoside dienes and the activity of ruthenium-based metathesis catalysts. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).


2002   Références trouvées : 1

Aucagne, V ; Aversa, MC ; Barattucci, A ; Bonaccorsi, P ; Giannetto, P ; Rollin, P ; Tatibouet, A  (2002)

Sulfenic acids in the carbohydrate field. Synthesis of transient glycosulfenic acids and their addition to unsaturated acceptors

Journal of Organic Chemistry 67 (20) 6925-6930
A new method is described for building up anomeric glycosyl sulfoxides, via the formation of transient glycosulfenic acids and their addition to unsaturated acceptors. Thermolysis of alpha- and beta-3- [(2,3,4,6-tetra-O-acetyl-D-glucopyranosyl)sulfinyl]propanenitriles affords 1-glucosulfenic acids, which are reacted in situ with common substituted alkynes. The obtained (R-s,E)-2-[(2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl)sulfinyl] -2-butendioates are involved as enantiopure sulfinyl dienophiles in Diels-Alder reactions with 2,3-dimethyl-1,3-butadiene to evaluate the role that the sugar moiety plays in the steric control of the cycloaddition. This chemistry provides a direct synthetic strategy for the stereocontrolled connection between thioglycon and aglycon moieties, thus offering the basis for an easy elaboration of new molecules incorporating thiosugar residues.

A new method is described for building up anomeric glycosyl sulfoxides, via the formation of transient glycosulfenic acids and their addition to unsaturated acceptors. Thermolysis of alpha- and beta-3- [(2,3,4,6-tetra-O-acetyl-D-glucopyranosyl)sulfinyl]propanenitriles affords 1-glucosulfenic acids, which are reacted in situ with common substituted alkynes. The obtained (R-s,E)-2-[(2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl)sulfinyl] -2-butendioates are involved as enantiopure sulfinyl dienophiles in Diels-Alder reactions with 2,3-dimethyl-1,3-butadiene to evaluate the role that the sugar moiety plays in the steric control of the cycloaddition. This chemistry provides a direct synthetic strategy for the stereocontrolled connection between thioglycon and aglycon moieties, thus offering the basis for an easy elaboration of new molecules incorporating thiosugar residues.


2000   Références trouvées : 1

Aucagne, V ; Gueyrard, D ; Tatibouet, A ; Quinsac, A ; Rollin, P  (2000)

Synthetic approaches to C-glucosinolates

Tetrahedron 56 (17) 2647-2654
In these pages, short and efficient synthetic approaches to C-analogs of glucosinolates are described. Starting from D-glucose, C-glucotropaeolin (6) and C-glucocapparin (11) were synthesized in three steps. Preliminary enzymatic assays involving sulfatase and myrosinase have been performed. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.

In these pages, short and efficient synthetic approaches to C-analogs of glucosinolates are described. Starting from D-glucose, C-glucotropaeolin (6) and C-glucocapparin (11) were synthesized in three steps. Preliminary enzymatic assays involving sulfatase and myrosinase have been performed. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.


1999   Références trouvées : 1

Aucagne, V ; Gueyrard, D ; Tatibouet, A ; Cottaz, S ; Driguez, H ; Lafosse, M ; Rollin, P  (1999)

The first synthesis of C-glucotropaeolin

Tetrahedron Letters 40 (41) 7319-7321


Mots-clés

Chargé de recherche , Protéines de synthèse et chimie bioorthogonale