You will find below the list of publications of all the members of the Peptides, Glycoconjugates and Metals in Biology research pole. For individual or theme-specific publications, please consult the research or the personal pages via the members list using the sidebar navigation tool.
2018 |
Clarifying the Copper Coordination Environment in a de Novo Designed Red Copper Protein Article de journal K J Koebke; L Ruckthong; J L Meagher; E Mathieu; J Harland; A Deb; N Lehnert; C Policar; C Tard; J E Penner-Hahn; J A Stuckey; V L Pecoraro Inorganic Chemistry, 57 (19), p. 12291–12302, 2018. @article{Koebke:2018, title = {Clarifying the Copper Coordination Environment in a de Novo Designed Red Copper Protein}, author = {K J Koebke and L Ruckthong and J L Meagher and E Mathieu and J Harland and A Deb and N Lehnert and C Policar and C Tard and J E Penner-Hahn and J A Stuckey and V L Pecoraro}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053716026&doi=10.1021%2facs.inorgchem.8b01989&partnerID=40&md5=1ff4fcf88039da93326134a5ecf32822}, doi = {10.1021/acs.inorgchem.8b01989}, year = {2018}, date = {2018-01-01}, journal = {Inorganic Chemistry}, volume = {57}, number = {19}, pages = {12291--12302}, abstract = {Cupredoxins are copper-dependent electron-transfer proteins that can be categorized as blue, purple, green, and red depending on the spectroscopic properties of the Cu(II) bound forms. Interestingly, despite significantly different first coordination spheres and nuclearity, all cupredoxins share a common Greek Key β-sheet fold. We have previously reported the design of a red copper protein within a completely distinct three-helical bundle protein, α3DChC2.(1)While this design demonstrated that a β-barrel fold was not requisite to recapitulate the properties of a native cupredoxin center, the parent peptide α3D was not sufficiently stable to allow further study through additional mutations. Here we present the design of an elongated protein GRANDα3D (GRα3D) with ΔGu = -11.4 kcal/mol compared to the original design's -5.1 kcal/mol. Diffraction quality crystals were grown of GRα3D (a first for an α3D peptide) and solved to a resolution of 1.34 r{A}. Examination of this structure suggested that Glu41 might interact with the Cu in our previously reported red copper protein. The previous bis(histidine)(cysteine) site (GRα3DChC2) was designed into this new scaffold and a series of variant constructs were made to explore this hypothesis. Mutation studies around Glu41 not only prove the proposed interaction, but also enabled tuning of the constructs' hyperfine coupling constant from 160 to 127 × 10-4 cm-1. X-ray absorption spectroscopy analysis is consistent with these hyperfine coupling differences being the result of variant 4p mixing related to coordination geometry changes. These studies not only prove that an Glu41-Cu interaction leads to the α3DChC2 construct's red copper protein like spectral properties, but also exemplify the exact control one can have in a de novo construct to tune the properties of an electron-transfer Cu site. Copyright © 2018 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Cupredoxins are copper-dependent electron-transfer proteins that can be categorized as blue, purple, green, and red depending on the spectroscopic properties of the Cu(II) bound forms. Interestingly, despite significantly different first coordination spheres and nuclearity, all cupredoxins share a common Greek Key β-sheet fold. We have previously reported the design of a red copper protein within a completely distinct three-helical bundle protein, α3DChC2.(1)While this design demonstrated that a β-barrel fold was not requisite to recapitulate the properties of a native cupredoxin center, the parent peptide α3D was not sufficiently stable to allow further study through additional mutations. Here we present the design of an elongated protein GRANDα3D (GRα3D) with ΔGu = -11.4 kcal/mol compared to the original design's -5.1 kcal/mol. Diffraction quality crystals were grown of GRα3D (a first for an α3D peptide) and solved to a resolution of 1.34 Å. Examination of this structure suggested that Glu41 might interact with the Cu in our previously reported red copper protein. The previous bis(histidine)(cysteine) site (GRα3DChC2) was designed into this new scaffold and a series of variant constructs were made to explore this hypothesis. Mutation studies around Glu41 not only prove the proposed interaction, but also enabled tuning of the constructs' hyperfine coupling constant from 160 to 127 × 10-4 cm-1. X-ray absorption spectroscopy analysis is consistent with these hyperfine coupling differences being the result of variant 4p mixing related to coordination geometry changes. These studies not only prove that an Glu41-Cu interaction leads to the α3DChC2 construct's red copper protein like spectral properties, but also exemplify the exact control one can have in a de novo construct to tune the properties of an electron-transfer Cu site. Copyright © 2018 American Chemical Society. |
Ferrocifens labelled with an infrared rhenium tricarbonyl tag: Synthesis, antiproliferative activity, quantification and nano IR mapping in cancer cells Article de journal Y Wang; F Heinemann; S Top; A Dazzi; C Policar; L Henry; F Lambert; G Jaouen; M Salmain; A Vessieres Dalton Transactions, 47 (29), p. 9824–9833, 2018. @article{Wang:2018c, title = {Ferrocifens labelled with an infrared rhenium tricarbonyl tag: Synthesis, antiproliferative activity, quantification and nano IR mapping in cancer cells}, author = {Y Wang and F Heinemann and S Top and A Dazzi and C Policar and L Henry and F Lambert and G Jaouen and M Salmain and A Vessieres}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85050854664&doi=10.1039%2fc8dt01582a&partnerID=40&md5=1eb695f8b77ceadad719c5ab75b11480}, doi = {10.1039/c8dt01582a}, year = {2018}, date = {2018-01-01}, journal = {Dalton Transactions}, volume = {47}, number = {29}, pages = {9824--9833}, abstract = {Antiproliferative activities of several members of the ferrocifen family, both in vitro and in vivo, are well documented although their precise location in cancer cells has not yet been elucidated. However, two different infrared imaging techniques have been used to map the non-cytotoxic cyrhetrenyl analogue of ferrociphenol in a single cell. This observation prompted us to tag two ferrocifens with a cyrhetrenyl unit [CpRe(CO)3; Cp = η5-cyclopentadienyl] by grafting it, via an ester bond, either to one of the phenols (4, 5) or to the hydroxypropyl chain (6). Complexes 4-6 retained a high cytotoxicity on breast cancer cells (MDA-MB-231) with IC50 values in the range 0.32-2.5 μM. Transmission IR spectroscopy was used to quantify the amount of cyrhetrenyl tag present in cells incubated with 5 or 6. The results show that after a 1-hour incubation of cells at 37 °C, complexes 5 and 6 are mainly present within cells while only a limited percentage, quantified by ICP-OES, remained in the incubation medium. AFM-IR spectroscopy, a technique coupling infrared irradiation with near-field AFM detection, was used to map the cyrhetrenyl unit in a single MDA-MB-231 cell, incubated at 37 °C for 1 hour with 10 μM of 6. The results show that signal distribution of the characteristic band of the Re(CO)3 entity at 1950 cm-1 matched those of amide and phosphate, thus indicating a location of the complex mainly in the cell nucleus. © 2018 The Royal Society of Chemistry.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Antiproliferative activities of several members of the ferrocifen family, both in vitro and in vivo, are well documented although their precise location in cancer cells has not yet been elucidated. However, two different infrared imaging techniques have been used to map the non-cytotoxic cyrhetrenyl analogue of ferrociphenol in a single cell. This observation prompted us to tag two ferrocifens with a cyrhetrenyl unit [CpRe(CO)3; Cp = η5-cyclopentadienyl] by grafting it, via an ester bond, either to one of the phenols (4, 5) or to the hydroxypropyl chain (6). Complexes 4-6 retained a high cytotoxicity on breast cancer cells (MDA-MB-231) with IC50 values in the range 0.32-2.5 μM. Transmission IR spectroscopy was used to quantify the amount of cyrhetrenyl tag present in cells incubated with 5 or 6. The results show that after a 1-hour incubation of cells at 37 °C, complexes 5 and 6 are mainly present within cells while only a limited percentage, quantified by ICP-OES, remained in the incubation medium. AFM-IR spectroscopy, a technique coupling infrared irradiation with near-field AFM detection, was used to map the cyrhetrenyl unit in a single MDA-MB-231 cell, incubated at 37 °C for 1 hour with 10 μM of 6. The results show that signal distribution of the characteristic band of the Re(CO)3 entity at 1950 cm-1 matched those of amide and phosphate, thus indicating a location of the complex mainly in the cell nucleus. © 2018 The Royal Society of Chemistry. |
Graftable SCoMPIs enable the labeling and X-ray fluorescence imaging of proteins Article de journal S Hostachy; M Masuda; T Miki; I Hamachi; S Sagan; O Lequin; K Medjoubi; A Somogyi; N Delsuc; C Policar Chemical Science, 9 (19), p. 4483–4487, 2018. @article{Hostachy:2018, title = {Graftable SCoMPIs enable the labeling and X-ray fluorescence imaging of proteins}, author = {S Hostachy and M Masuda and T Miki and I Hamachi and S Sagan and O Lequin and K Medjoubi and A Somogyi and N Delsuc and C Policar}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047244059&doi=10.1039%2fc8sc00886h&partnerID=40&md5=4625eaa891ccc665a2357b73e20e3541}, doi = {10.1039/c8sc00886h}, year = {2018}, date = {2018-01-01}, journal = {Chemical Science}, volume = {9}, number = {19}, pages = {4483--4487}, abstract = {Bio-imaging techniques alternative to fluorescence microscopy are gaining increasing interest as complementary tools to visualize and analyze biological systems. Among them, X-ray fluorescence microspectroscopy provides information on the local content and distribution of heavy elements (Z ≥ 14) in cells or biological samples. In this context, similar tools to those developed for fluorescence microscopy are desired, including chemical probes or tags. In this work, we study rhenium complexes as a convenient and sensitive probe for X-ray fluorescence microspectroscopy. We demonstrate their ability to label and sense exogenously incubated or endogenous proteins inside cells. © The Royal Society of Chemistry 2018.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Bio-imaging techniques alternative to fluorescence microscopy are gaining increasing interest as complementary tools to visualize and analyze biological systems. Among them, X-ray fluorescence microspectroscopy provides information on the local content and distribution of heavy elements (Z ≥ 14) in cells or biological samples. In this context, similar tools to those developed for fluorescence microscopy are desired, including chemical probes or tags. In this work, we study rhenium complexes as a convenient and sensitive probe for X-ray fluorescence microspectroscopy. We demonstrate their ability to label and sense exogenously incubated or endogenous proteins inside cells. © The Royal Society of Chemistry 2018. |
Labeling of Hyaluronic Acids with a Rhenium-tricarbonyl Tag and Percutaneous Penetration Studied by Multimodal Imaging Article de journal L Henry; N Delsuc; C Laugel; F Lambert; C Sandt; S Hostachy; A -S Bernard; H C Bertrand; L Grimaud; A Baillet-Guffroy; C Policar Bioconjugate Chemistry, 29 (4), p. 987–991, 2018. @article{Henry:2018, title = {Labeling of Hyaluronic Acids with a Rhenium-tricarbonyl Tag and Percutaneous Penetration Studied by Multimodal Imaging}, author = {L Henry and N Delsuc and C Laugel and F Lambert and C Sandt and S Hostachy and A -S Bernard and H C Bertrand and L Grimaud and A Baillet-Guffroy and C Policar}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85045549363&doi=10.1021%2facs.bioconjchem.7b00825&partnerID=40&md5=87140714a264358836c5f4c7734e49a3}, doi = {10.1021/acs.bioconjchem.7b00825}, year = {2018}, date = {2018-01-01}, journal = {Bioconjugate Chemistry}, volume = {29}, number = {4}, pages = {987--991}, abstract = {Hyaluronic acids were labeled with a rhenium-tricarbonyl used as single core multimodal probe for imaging and their penetration into human skin biopsies was studied using IR microscopy and fluorescence imaging (labeled SCoMPI). The penetration was shown to be dependent on the molecular weight of the molecule and limited to the upper layer of the skin. © 2018 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Hyaluronic acids were labeled with a rhenium-tricarbonyl used as single core multimodal probe for imaging and their penetration into human skin biopsies was studied using IR microscopy and fluorescence imaging (labeled SCoMPI). The penetration was shown to be dependent on the molecular weight of the molecule and limited to the upper layer of the skin. © 2018 American Chemical Society. |
A Metallo Pro-Drug to Target CuII in the Context of Alzheimer's Disease Article de journal A Conte-Daban; V Ambike; R Guillot; N Delsuc; C Policar; C Hureau Chemistry - A European Journal, 24 (20), p. 5095–5099, 2018. @article{Conte-Daban:2018, title = {A Metallo Pro-Drug to Target CuII in the Context of Alzheimer's Disease}, author = {A Conte-Daban and V Ambike and R Guillot and N Delsuc and C Policar and C Hureau}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85045131927&doi=10.1002%2fchem.201706049&partnerID=40&md5=5dc310a9e12535e296ba5429250159d3}, doi = {10.1002/chem.201706049}, year = {2018}, date = {2018-01-01}, journal = {Chemistry - A European Journal}, volume = {24}, number = {20}, pages = {5095--5099}, abstract = {Alzheimer's disease and oxidative stress are connected. In the present communication, we report the use of a MnII-based superoxide dismutase (SOD) mimic ([MnII(L)]+, 1+) as a pro-drug candidate to target CuII-associated events, namely, CuII-induced formation of reactive oxygen species (ROS) and modulation of the amyloid-β (Aβ) peptide aggregation. Complex 1+ is able to remove CuII from Aβ, stop ROS and prevent alteration of Aβ aggregation as would do the corresponding free ligand LH. Using 1+ instead of LH in further biological applications would have the double advantage to avoid the cell toxicity of LH and to benefit from its proved SOD-like activity. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim}, keywords = {}, pubstate = {published}, tppubtype = {article} } Alzheimer's disease and oxidative stress are connected. In the present communication, we report the use of a MnII-based superoxide dismutase (SOD) mimic ([MnII(L)]+, 1+) as a pro-drug candidate to target CuII-associated events, namely, CuII-induced formation of reactive oxygen species (ROS) and modulation of the amyloid-β (Aβ) peptide aggregation. Complex 1+ is able to remove CuII from Aβ, stop ROS and prevent alteration of Aβ aggregation as would do the corresponding free ligand LH. Using 1+ instead of LH in further biological applications would have the double advantage to avoid the cell toxicity of LH and to benefit from its proved SOD-like activity. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim |
Macrophage-derived superoxide production and antioxidant response following skeletal muscle injury Article de journal E Le Moal; G Juban; A S Bernard; T Varga; C Policar; B Chazaud; R Mounier Free Radical Biology and Medicine, 120 , p. 33–40, 2018. @article{LeMoal:2018, title = {Macrophage-derived superoxide production and antioxidant response following skeletal muscle injury}, author = {E Le Moal and G Juban and A S Bernard and T Varga and C Policar and B Chazaud and R Mounier}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044047057&doi=10.1016%2fj.freeradbiomed.2018.02.024&partnerID=40&md5=3d7a016c57bd52dfee180ac22ee70ae8}, doi = {10.1016/j.freeradbiomed.2018.02.024}, year = {2018}, date = {2018-01-01}, journal = {Free Radical Biology and Medicine}, volume = {120}, pages = {33--40}, abstract = {Macrophages are key players of immunity that display different functions according to their activation states. In a regenerative context, pro-inflammatory macrophages (Ly6Cpos) are involved in the mounting of the inflammatory response whereas anti-inflammatory macrophages (Ly6Cneg) dampen the inflammation and promote tissue repair. Reactive oxygen species (ROS) production is a hallmark of tissue injury and of subsequent inflammation as described in a bacterial challenge context. However, whether macrophages produce ROS following a sterile tissue injury is uncertain. In this study, we used complementary in vitro, ex vivo and in vivo experiments in mouse to show that macrophages do not release ROS following a sterile injury in skeletal muscle. Furthermore, expression profiles of genes involved in the response to oxidative stress in Ly6Cpos and Ly6Cneg macrophage subsets did not indicate any antioxidant response in this context. Finally, in vivo, pharmacological antioxidant supplementation with N-Acetyl-cysteine (NAC) following skeletal muscle injury did not alter macrophage phenotype during skeletal muscle regeneration. Overall, these results indicate that following a sterile injury, macrophage-derived ROS release is not involved in the regulation of the inflammatory response in the regenerating skeletal muscle. © 2018 Elsevier Inc.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Macrophages are key players of immunity that display different functions according to their activation states. In a regenerative context, pro-inflammatory macrophages (Ly6Cpos) are involved in the mounting of the inflammatory response whereas anti-inflammatory macrophages (Ly6Cneg) dampen the inflammation and promote tissue repair. Reactive oxygen species (ROS) production is a hallmark of tissue injury and of subsequent inflammation as described in a bacterial challenge context. However, whether macrophages produce ROS following a sterile tissue injury is uncertain. In this study, we used complementary in vitro, ex vivo and in vivo experiments in mouse to show that macrophages do not release ROS following a sterile injury in skeletal muscle. Furthermore, expression profiles of genes involved in the response to oxidative stress in Ly6Cpos and Ly6Cneg macrophage subsets did not indicate any antioxidant response in this context. Finally, in vivo, pharmacological antioxidant supplementation with N-Acetyl-cysteine (NAC) following skeletal muscle injury did not alter macrophage phenotype during skeletal muscle regeneration. Overall, these results indicate that following a sterile injury, macrophage-derived ROS release is not involved in the regulation of the inflammatory response in the regenerating skeletal muscle. © 2018 Elsevier Inc. |
GPCR modulation in breast cancer Article de journal R Lappano; Y Jacquot; M Maggiolini International Journal of Molecular Sciences, 19 (12), 2018. @article{Lappano:2018, title = {GPCR modulation in breast cancer}, author = {R Lappano and Y Jacquot and M Maggiolini}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85057977359&doi=10.3390%2fijms19123840&partnerID=40&md5=2eda31a7898bc134fec0136f301bf16a}, doi = {10.3390/ijms19123840}, year = {2018}, date = {2018-01-01}, journal = {International Journal of Molecular Sciences}, volume = {19}, number = {12}, abstract = {Breast cancer is the most prevalent cancer found in women living in developed countries. Endocrine therapy is the mainstay of treatment for hormone-responsive breast tumors (about 70% of all breast cancers) and implies the use of selective estrogen receptor modulators and aromatase inhibitors. In contrast, triple-negative breast cancer (TNBC), a highly heterogeneous disease that may account for up to 24% of all newly diagnosed cases, is hormone-independent and characterized by a poor prognosis. As drug resistance is common in all breast cancer subtypes despite the different treatment modalities, novel therapies targeting signaling transduction pathways involved in the processes of breast carcinogenesis, tumor promotion and metastasis have been subject to accurate consideration. G protein-coupled receptors (GPCRs) are the largest family of cell-surface receptors involved in the development and progression of many tumors including breast cancer. Here we discuss data regarding GPCR-mediated signaling, pharmacological properties and biological outputs toward breast cancer tumorigenesis and metastasis. Furthermore, we address several drugs that have shown an unexpected opportunity to interfere with GPCR-based breast tumorigenic signals. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Breast cancer is the most prevalent cancer found in women living in developed countries. Endocrine therapy is the mainstay of treatment for hormone-responsive breast tumors (about 70% of all breast cancers) and implies the use of selective estrogen receptor modulators and aromatase inhibitors. In contrast, triple-negative breast cancer (TNBC), a highly heterogeneous disease that may account for up to 24% of all newly diagnosed cases, is hormone-independent and characterized by a poor prognosis. As drug resistance is common in all breast cancer subtypes despite the different treatment modalities, novel therapies targeting signaling transduction pathways involved in the processes of breast carcinogenesis, tumor promotion and metastasis have been subject to accurate consideration. G protein-coupled receptors (GPCRs) are the largest family of cell-surface receptors involved in the development and progression of many tumors including breast cancer. Here we discuss data regarding GPCR-mediated signaling, pharmacological properties and biological outputs toward breast cancer tumorigenesis and metastasis. Furthermore, we address several drugs that have shown an unexpected opportunity to interfere with GPCR-based breast tumorigenic signals. © 2018 by the authors. Licensee MDPI, Basel, Switzerland. |
Rhenium tricarbonyl complexes with arenethiolate axial ligands Article de journal M He; H Y V Ching; C Policar; H C Bertrand New Journal of Chemistry, 42 (14), p. 11312–11323, 2018. @article{He:2018, title = {Rhenium tricarbonyl complexes with arenethiolate axial ligands}, author = {M He and H Y V Ching and C Policar and H C Bertrand}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85049750977&doi=10.1039%2fc8nj01960f&partnerID=40&md5=eac4613cb3f849f5a149c72a46384912}, doi = {10.1039/c8nj01960f}, year = {2018}, date = {2018-01-01}, journal = {New Journal of Chemistry}, volume = {42}, number = {14}, pages = {11312--11323}, abstract = {Due to their unique electronic and photophysical properties, rhenium(i) fac-tricarbonyl complexes of general formula [Re(NtextasciicircumN)(CO)3X]n+ have been arousing constant interest in many diverse fields and applications, such as CO2 (photo)electroreduction, organic light emitting diodes and materials, sensors, biological applications and bio-imaging. The photophysical properties of [Re(NtextasciicircumN)(CO)3X]n+ complexes can be modulated by structural variations of the ligands. Modifications of the NtextasciicircumN diimine ligand and of the axial X ligand have been deeply investigated. However, thiolate ligands have scarcely been used in the synthesis of rhenium tricarbonyl complexes. We describe the synthesis of a series of Pyta and Tapy-based Re(i) fac-tricarbonyl complexes with diversely para-substituted arenethiolates in the coordination sphere and report on the electrochemical, photophysical properties and DFT studies of such complexes. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Due to their unique electronic and photophysical properties, rhenium(i) fac-tricarbonyl complexes of general formula [Re(NtextasciicircumN)(CO)3X]n+ have been arousing constant interest in many diverse fields and applications, such as CO2 (photo)electroreduction, organic light emitting diodes and materials, sensors, biological applications and bio-imaging. The photophysical properties of [Re(NtextasciicircumN)(CO)3X]n+ complexes can be modulated by structural variations of the ligands. Modifications of the NtextasciicircumN diimine ligand and of the axial X ligand have been deeply investigated. However, thiolate ligands have scarcely been used in the synthesis of rhenium tricarbonyl complexes. We describe the synthesis of a series of Pyta and Tapy-based Re(i) fac-tricarbonyl complexes with diversely para-substituted arenethiolates in the coordination sphere and report on the electrochemical, photophysical properties and DFT studies of such complexes. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique. |
Probing the in-air growth of large area of 3D functional structures into a 2D supramolecular nanoporous network Article de journal R Brisse; D Guianvarc'h; C Mansuy; S Sagan; D Kreher; L Sosa-Vargas; L Hamitouche; V Humblot; I Arfaoui; V Labet; C Paris; C Petit; A -J Attias Chemical Communications, 54 (72), p. 10068–10071, 2018. @article{Brisse:2018, title = {Probing the in-air growth of large area of 3D functional structures into a 2D supramolecular nanoporous network}, author = {R Brisse and D Guianvarc'h and C Mansuy and S Sagan and D Kreher and L Sosa-Vargas and L Hamitouche and V Humblot and I Arfaoui and V Labet and C Paris and C Petit and A -J Attias}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053165096&doi=10.1039%2fC8CC06125D&partnerID=40&md5=0fc8e0f5c85451c72df0638b78a31224}, doi = {10.1039/C8CC06125D}, year = {2018}, date = {2018-01-01}, journal = {Chemical Communications}, volume = {54}, number = {72}, pages = {10068--10071}, abstract = {Surface-confined host-guest chemistry at the air/solid interface is used for trapping a functionalized 3D Zn-phthalocyanine complex into a 2D porous supramolecular template allowing the large area functionalization of an sp2-hybridized carbon-based substrate as evidenced by STM, resonance Raman spectroscopy, and water contact angle measurements. © The Royal Society of Chemistry.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Surface-confined host-guest chemistry at the air/solid interface is used for trapping a functionalized 3D Zn-phthalocyanine complex into a 2D porous supramolecular template allowing the large area functionalization of an sp2-hybridized carbon-based substrate as evidenced by STM, resonance Raman spectroscopy, and water contact angle measurements. © The Royal Society of Chemistry. |
Synthesis, Oligonucleotide Incorporation and Fluorescence Properties in DNA of a Bicyclic Thymine Analogue Article de journal Christopher P Lawson; Anders F Füchtbauer; Moa S Wranne; Tristan Giraud; Thomas Floyd; Blaise Dumat; Nicolai K Andersen; Afaf H. El-Sagheer; Tom Brown; Henrik Gradén; Marcus L Wilhelmsson; Morten Grøtli Scientific Reports, 8 (1), p. 1-9, 2018, ISSN: 4159801831897. @article{Lawson:2018, title = {Synthesis, Oligonucleotide Incorporation and Fluorescence Properties in DNA of a Bicyclic Thymine Analogue}, author = {Christopher P Lawson and Anders F F\"{u}chtbauer and Moa S Wranne and Tristan Giraud and Thomas Floyd and Blaise Dumat and Nicolai K Andersen and Afaf {H. El-Sagheer} and Tom Brown and Henrik Grad\'{e}n and Marcus L Wilhelmsson and Morten Gr\otli}, doi = {10.1038/s41598-018-31897-2}, issn = {4159801831897}, year = {2018}, date = {2018-01-01}, journal = {Scientific Reports}, volume = {8}, number = {1}, pages = {1-9}, abstract = {Fluorescent base analogues (FBAs) have emerged as a powerful class of molecular reporters of location and environment for nucleic acids. In our overall mission to develop bright and useful FBAs for all natural nucleobases, herein we describe the synthesis and thorough characterization of bicyclic thymidine (bT), both as a monomer and when incorporated into DNA. We have developed a robust synthetic route for the preparation of the bT DNA monomer and the corresponding protected phosphoramidite for solid-phase DNA synthesis. The bT deoxyribonucleoside has a brightness value of 790 M-1cm-1 in water, which is comparable or higher than most fluorescent thymine analogues reported. When incorporated into DNA, bT pairs selectively with adenine without perturbing the B-form structure, keeping the melting thermodynamics of the B-form duplex DNA virtually unchanged. As for most fluorescent base analogues, the emission of bT is reduced inside DNA (4.5- and 13-fold in single- and double-stranded DNA, respectively). Overall, these properties make bT an interesting thymine analogue for studying DNA and an excellent starting point for the development of brighter bT derivatives.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Fluorescent base analogues (FBAs) have emerged as a powerful class of molecular reporters of location and environment for nucleic acids. In our overall mission to develop bright and useful FBAs for all natural nucleobases, herein we describe the synthesis and thorough characterization of bicyclic thymidine (bT), both as a monomer and when incorporated into DNA. We have developed a robust synthetic route for the preparation of the bT DNA monomer and the corresponding protected phosphoramidite for solid-phase DNA synthesis. The bT deoxyribonucleoside has a brightness value of 790 M-1cm-1 in water, which is comparable or higher than most fluorescent thymine analogues reported. When incorporated into DNA, bT pairs selectively with adenine without perturbing the B-form structure, keeping the melting thermodynamics of the B-form duplex DNA virtually unchanged. As for most fluorescent base analogues, the emission of bT is reduced inside DNA (4.5- and 13-fold in single- and double-stranded DNA, respectively). Overall, these properties make bT an interesting thymine analogue for studying DNA and an excellent starting point for the development of brighter bT derivatives. |
Taming Nickel-Catalyzed Suzuki-Miyaura Coupling: A Mechanistic Focus on Boron-to-Nickel Transmetalation Article de journal P -A Payard; L A Perego; I Ciofini; L Grimaud ACS Catalysis, 8 (6), p. 4812–4823, 2018. @article{Payard:2018a, title = {Taming Nickel-Catalyzed Suzuki-Miyaura Coupling: A Mechanistic Focus on Boron-to-Nickel Transmetalation}, author = {P -A Payard and L A Perego and I Ciofini and L Grimaud}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85046455355&doi=10.1021%2facscatal.8b00933&partnerID=40&md5=caf0fb0bb4baa9b47d85ebce2e2b0045}, doi = {10.1021/acscatal.8b00933}, year = {2018}, date = {2018-01-01}, journal = {ACS Catalysis}, volume = {8}, number = {6}, pages = {4812--4823}, abstract = {The mechanism of boron-to-nickel transmetalation, the key step of the nickel-catalyzed Suzuki-Miyaura (S-M) coupling, was examined both experimentally and theoretically. Dinuclear μ-hydroxo-bridged complexes formed by reaction of trans-[ArNi(PR3)2X] with hydroxide are not directly involved in transmetalation, but they rather act as a resting state for the catalyst. The base/boronic acid ratio is the crucial parameter, as it modulates the extent of formation of these dinuclear species and thus tunes the catalytic activity. These findings explain some limitations encountered in practical applications of nickel-catalyzed S-M couplings and suggest how to tailor the experimental conditions in order to overcome these difficulties. © 2018 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The mechanism of boron-to-nickel transmetalation, the key step of the nickel-catalyzed Suzuki-Miyaura (S-M) coupling, was examined both experimentally and theoretically. Dinuclear μ-hydroxo-bridged complexes formed by reaction of trans-[ArNi(PR3)2X] with hydroxide are not directly involved in transmetalation, but they rather act as a resting state for the catalyst. The base/boronic acid ratio is the crucial parameter, as it modulates the extent of formation of these dinuclear species and thus tunes the catalytic activity. These findings explain some limitations encountered in practical applications of nickel-catalyzed S-M couplings and suggest how to tailor the experimental conditions in order to overcome these difficulties. © 2018 American Chemical Society. |
TiCl 4 -Mediated Synthesis of 3,4-Hetero-Disubstituted Isocoumarins by Means of Isocyanide Insertion Reactions Article de journal S Ponra; A Nyadanu; S Maurin; L El Kaïm; L Grimaud; M R Vitale Synthesis (Germany), 50 (6), p. 1331–1342, 2018. @article{Ponra:2018, title = {TiCl 4 -Mediated Synthesis of 3,4-Hetero-Disubstituted Isocoumarins by Means of Isocyanide Insertion Reactions}, author = {S Ponra and A Nyadanu and S Maurin and L El Ka\"{i}m and L Grimaud and M R Vitale}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85038371806&doi=10.1055%2fs-0036-1591733&partnerID=40&md5=baf4a0e29e4d642c2aeebdd1b35bb541}, doi = {10.1055/s-0036-1591733}, year = {2018}, date = {2018-01-01}, journal = {Synthesis (Germany)}, volume = {50}, number = {6}, pages = {1331--1342}, abstract = {The isocyanide insertion into sulfanyl-phthalides under Lewis acid conditions is reported with full details. This sequential three-component reaction affords a new straightforward and highly convenient method for the preparation of 3-amino-4-sulfanyl isocoumarins, the potential of which is still unexplored.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The isocyanide insertion into sulfanyl-phthalides under Lewis acid conditions is reported with full details. This sequential three-component reaction affords a new straightforward and highly convenient method for the preparation of 3-amino-4-sulfanyl isocoumarins, the potential of which is still unexplored. |
Evidence for a Cooperative Mechanism Involving Two Palladium(0) Centers in the Oxidative Addition of Iodoarenes Article de journal L A Perego; P -A Payard; B Haddou; I Ciofini; L Grimaud Chemistry - A European Journal, 24 (9), p. 2192–2199, 2018. @article{Perego:2018, title = {Evidence for a Cooperative Mechanism Involving Two Palladium(0) Centers in the Oxidative Addition of Iodoarenes}, author = {L A Perego and P -A Payard and B Haddou and I Ciofini and L Grimaud}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040731231&doi=10.1002%2fchem.201704899&partnerID=40&md5=04a20da1a343e3ea2009facbdde3fbd9}, doi = {10.1002/chem.201704899}, year = {2018}, date = {2018-01-01}, journal = {Chemistry - A European Journal}, volume = {24}, number = {9}, pages = {2192--2199}, abstract = {Oxidative addition of iodoarenes (ArI) to Pd0 ligated by 1-methyl-1H-imidazole (mim) in polar solvents leads to cationic arylpalladium(II) complexes [ArPd(mim)3]+. Kinetic analyses evidence that this reaction is second order with respect to the concentration of Pd0, and a mechanism involving the cooperative intervention of two Pd0 centers has been postulated to explain this finding. This unusual behavior is also observed with other nitrogen-containing ligands and it is general for iodobenzenes substituted with electron-donating or weakly electron-withdrawing groups. In contrast, bromoarenes and electron-poor iodoarenes display first-order kinetics with respect to Pd0. Theoretical calculations performed at the density functional theory (DFT) level suggest the existence of mim-ligated ArI-Pd0 complexes, in which the iodoarene is bound to the metal in a halogen-bond-like fashion. Coordination weakens the C−I bond and facilitates the oxidative insertion of another Pd0 center across this C−I bond. This conceptually novel mechanism, involving the cooperative participation of two distinct metal centers, allows a full explanation of the experimentally observed kinetics. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim}, keywords = {}, pubstate = {published}, tppubtype = {article} } Oxidative addition of iodoarenes (ArI) to Pd0 ligated by 1-methyl-1H-imidazole (mim) in polar solvents leads to cationic arylpalladium(II) complexes [ArPd(mim)3]+. Kinetic analyses evidence that this reaction is second order with respect to the concentration of Pd0, and a mechanism involving the cooperative intervention of two Pd0 centers has been postulated to explain this finding. This unusual behavior is also observed with other nitrogen-containing ligands and it is general for iodobenzenes substituted with electron-donating or weakly electron-withdrawing groups. In contrast, bromoarenes and electron-poor iodoarenes display first-order kinetics with respect to Pd0. Theoretical calculations performed at the density functional theory (DFT) level suggest the existence of mim-ligated ArI-Pd0 complexes, in which the iodoarene is bound to the metal in a halogen-bond-like fashion. Coordination weakens the C−I bond and facilitates the oxidative insertion of another Pd0 center across this C−I bond. This conceptually novel mechanism, involving the cooperative participation of two distinct metal centers, allows a full explanation of the experimentally observed kinetics. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim |
4-Aminopyrimidine libraries from the Ugi-Smiles reaction of thiouracil Article de journal M A Sidhoum; L El Kaïm; L Grimaud Tetrahedron, 74 (38), p. 5222–5231, 2018. @article{Sidhoum:2018, title = {4-Aminopyrimidine libraries from the Ugi-Smiles reaction of thiouracil}, author = {M A Sidhoum and L El Ka\"{i}m and L Grimaud}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85046157652&doi=10.1016%2fj.tet.2018.04.058&partnerID=40&md5=fe5adb80c898e954107e7970320ea457}, doi = {10.1016/j.tet.2018.04.058}, year = {2018}, date = {2018-01-01}, journal = {Tetrahedron}, volume = {74}, number = {38}, pages = {5222--5231}, abstract = {The Ugi-Smiles reaction of S-benzyl thiouracil have been exploited in several three-step sequences for the preparation of aminopyrimidine libraries with high diversity. After the 4-component coupling, oxidation of the thioether to sulfone is followed by displacement of the latter by various carbon-centered nucleophiles (cyanide, malonate, boronic acids) or amines. The efficiency of the whole sequence was further demonstrated with one-pot procedures. © 2018}, keywords = {}, pubstate = {published}, tppubtype = {article} } The Ugi-Smiles reaction of S-benzyl thiouracil have been exploited in several three-step sequences for the preparation of aminopyrimidine libraries with high diversity. After the 4-component coupling, oxidation of the thioether to sulfone is followed by displacement of the latter by various carbon-centered nucleophiles (cyanide, malonate, boronic acids) or amines. The efficiency of the whole sequence was further demonstrated with one-pot procedures. © 2018 |
X Liu; L Hu; N Pan; L Grimaud; E Labbé; O Buriez; J Delacotte; F Lemaître; M Guille-Collignon Biophysical Chemistry, 235 , p. 48–55, 2018. @article{Liu:2018, title = {Coupling electrochemistry and TIRF-microscopy with the fluorescent false neurotransmitter FFN102 supports the fluorescence signals during single vesicle exocytosis detection}, author = {X Liu and L Hu and N Pan and L Grimaud and E Labb\'{e} and O Buriez and J Delacotte and F Lema\^{i}tre and M Guille-Collignon}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85042352158&doi=10.1016%2fj.bpc.2018.02.004&partnerID=40&md5=365430d79a0d526895e755729264d88f}, doi = {10.1016/j.bpc.2018.02.004}, year = {2018}, date = {2018-01-01}, journal = {Biophysical Chemistry}, volume = {235}, pages = {48--55}, abstract = {Applications of the Fluorescent False Neurotransmitter FFN102, an analog of biogenic neurotransmitters and a suitable probe for coupled amperometry and TIRFM (total internal reflexion fluorescence microscopy) investigations of exocytotic secretion, were considered here. The electroactivity of FFN102 was shown to very likely arise from the oxidation of its phenolic group through a CE (Chemical-Electrochemical) mechanism. Evidences that the aminoethyl group of FFN102 is the key recognition element by BON N13 cells were also provided. Amperometric measurements were then performed at the single cell level with carbon fiber electrode (CFE) or Indium Tin Oxide (ITO) surfaces. It proved the disparity of kinetic and quantitative parameters of FFN102-stained cells acquired either at cell top and bottom. Moreover, coupled analyses of FFN102 loaded vesicles allowed us to classify three types of optical signals that probably arise from secretion releases thanks to their concomitant detection with an electrochemical spike. Finally, preliminary benefits from the coupling involving FFN102 were reported in terms of origins of overlapped amperometric spikes or assignment of fluorescence extinctions to real exocytotic events. © 2018 Elsevier B.V.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Applications of the Fluorescent False Neurotransmitter FFN102, an analog of biogenic neurotransmitters and a suitable probe for coupled amperometry and TIRFM (total internal reflexion fluorescence microscopy) investigations of exocytotic secretion, were considered here. The electroactivity of FFN102 was shown to very likely arise from the oxidation of its phenolic group through a CE (Chemical-Electrochemical) mechanism. Evidences that the aminoethyl group of FFN102 is the key recognition element by BON N13 cells were also provided. Amperometric measurements were then performed at the single cell level with carbon fiber electrode (CFE) or Indium Tin Oxide (ITO) surfaces. It proved the disparity of kinetic and quantitative parameters of FFN102-stained cells acquired either at cell top and bottom. Moreover, coupled analyses of FFN102 loaded vesicles allowed us to classify three types of optical signals that probably arise from secretion releases thanks to their concomitant detection with an electrochemical spike. Finally, preliminary benefits from the coupling involving FFN102 were reported in terms of origins of overlapped amperometric spikes or assignment of fluorescence extinctions to real exocytotic events. © 2018 Elsevier B.V. |
Direct Amination of Alcohols Catalyzed by Aluminum Triflate: An Experimental and Computational Study Article de journal P -A Payard; Q Gu; W Guo; Q Wang; M Corbet; C Michel; P Sautet; L Grimaud; R Wischert; M Pera-Titus Chemistry - A European Journal, 24 (53), p. 14146–14153, 2018. @article{Payard:2018, title = {Direct Amination of Alcohols Catalyzed by Aluminum Triflate: An Experimental and Computational Study}, author = {P -A Payard and Q Gu and W Guo and Q Wang and M Corbet and C Michel and P Sautet and L Grimaud and R Wischert and M Pera-Titus}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053248652&doi=10.1002%2fchem.201801492&partnerID=40&md5=a6e7d7f00f17b7ee47043050e85e7e2a}, doi = {10.1002/chem.201801492}, year = {2018}, date = {2018-01-01}, journal = {Chemistry - A European Journal}, volume = {24}, number = {53}, pages = {14146--14153}, abstract = {Among the best-performing homogeneous catalysts for the direct amination of activated secondary alcohols with electron-poor amine derivatives, metal triflates, such as aluminum triflate, Al(OTf)3, stand out. Herein we report the extension of this reaction to electron-rich amines and activated primary alcohols. We provide detailed insight into the structure and reactivity of the catalyst under working conditions in both nitromethane and toluene solvent, through experiment (cyclic voltammetry, conductimetry, NMR spectroscopy), and density functional theory (DFT) simulations. Competition between aniline and benzyl alcohol for Al in the two solvents explains the different reactivities. The catalyst structures predicted from the DFT calculations were validated by the experiments. Whereas a SN1-type mechanism was found to be active in nitromethane, we propose a SN2 mechanism in toluene to rationalize the much higher selectivity observed when using this solvent. Also, unlike what is commonly assumed in homogeneous catalysis, we show that different active species may be active instead of only one. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim}, keywords = {}, pubstate = {published}, tppubtype = {article} } Among the best-performing homogeneous catalysts for the direct amination of activated secondary alcohols with electron-poor amine derivatives, metal triflates, such as aluminum triflate, Al(OTf)3, stand out. Herein we report the extension of this reaction to electron-rich amines and activated primary alcohols. We provide detailed insight into the structure and reactivity of the catalyst under working conditions in both nitromethane and toluene solvent, through experiment (cyclic voltammetry, conductimetry, NMR spectroscopy), and density functional theory (DFT) simulations. Competition between aniline and benzyl alcohol for Al in the two solvents explains the different reactivities. The catalyst structures predicted from the DFT calculations were validated by the experiments. Whereas a SN1-type mechanism was found to be active in nitromethane, we propose a SN2 mechanism in toluene to rationalize the much higher selectivity observed when using this solvent. Also, unlike what is commonly assumed in homogeneous catalysis, we show that different active species may be active instead of only one. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim |
A novel diarylethene-based photoswitchable chelator for reversible release and capture of Ca2+ in aqueous media Article de journal N Dozova; G Pousse; B Barnych; J -M Mallet; J Cossy; B Valeur; P Plaza Journal of Photochemistry and Photobiology A: Chemistry, 360 , p. 181–187, 2018. @article{Dozova:2018, title = {A novel diarylethene-based photoswitchable chelator for reversible release and capture of Ca2+ in aqueous media}, author = {N Dozova and G Pousse and B Barnych and J -M Mallet and J Cossy and B Valeur and P Plaza}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85046375200&doi=10.1016%2fj.jphotochem.2018.04.029&partnerID=40&md5=acfff9bc55e2d0bb41580e84374018fc}, doi = {10.1016/j.jphotochem.2018.04.029}, year = {2018}, date = {2018-01-01}, journal = {Journal of Photochemistry and Photobiology A: Chemistry}, volume = {360}, pages = {181--187}, abstract = {The synthesis and characterisation of a novel Reversibly Photoswitchable Chelator (RPC) of calcium ions, designed as a stepping stone towards producing pulses of calcium concentration in an aqueous environment, is reported. This RPC is constituted of a photochromic diarylethene core connected on one side to a BAPTA (1,2-bis(2-aminophenoxy)ethane-N,N,N’,N’-tetraacetic acid) calcium chelator and, on the other side, to an electron-withdrawing group. The operation principle consists in photoswitching on and off an intramolecular charge transfer between one nitrogen atom of the BAPTA moiety and the electron-withdrawing group, thereby modulating the chelating affinity of BAPTA for calcium ions. Solubility of the compound in a partially aqueous solvent was achieved by grafting a short PEG (polyethylene glycol) tail to the electron-withdrawing group. A reduction of the affinity for calcium ions upon photoswitching by a factor of 3\textendash4, in the hundred nM range of dissociation constant, is reported and constitutes a proof of concept of this type of RPC. © 2018 Elsevier B.V.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The synthesis and characterisation of a novel Reversibly Photoswitchable Chelator (RPC) of calcium ions, designed as a stepping stone towards producing pulses of calcium concentration in an aqueous environment, is reported. This RPC is constituted of a photochromic diarylethene core connected on one side to a BAPTA (1,2-bis(2-aminophenoxy)ethane-N,N,N’,N’-tetraacetic acid) calcium chelator and, on the other side, to an electron-withdrawing group. The operation principle consists in photoswitching on and off an intramolecular charge transfer between one nitrogen atom of the BAPTA moiety and the electron-withdrawing group, thereby modulating the chelating affinity of BAPTA for calcium ions. Solubility of the compound in a partially aqueous solvent was achieved by grafting a short PEG (polyethylene glycol) tail to the electron-withdrawing group. A reduction of the affinity for calcium ions upon photoswitching by a factor of 3–4, in the hundred nM range of dissociation constant, is reported and constitutes a proof of concept of this type of RPC. © 2018 Elsevier B.V. |
Electrochemical switching fluorescence emission in rhodamine derivatives Article de journal M Čížková; L Cattiaux; J -M Mallet; E Labbé; O Buriez Electrochimica Acta, 260 , p. 589–597, 2018. @article{Cizkova:2018a, title = {Electrochemical switching fluorescence emission in rhodamine derivatives}, author = {M \v{C}\'{i}\v{z}kov\'{a} and L Cattiaux and J -M Mallet and E Labb\'{e} and O Buriez}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85038870042&doi=10.1016%2fj.electacta.2017.12.104&partnerID=40&md5=6a1537d7de8ad37549ef796b0c6f2642}, doi = {10.1016/j.electacta.2017.12.104}, year = {2018}, date = {2018-01-01}, journal = {Electrochimica Acta}, volume = {260}, pages = {589--597}, abstract = {Three rhodamine derivatives exhibiting electrofluorochromic properties were investigated by cyclic voltammetry and UV\textendashVis/fluorescence spectroelectrochemistry. Rhodamine 101 (Rh101, compound 1) was used as a reference model. In compound 2, the carboxylate anion of Rh101 was replaced by an alkyne moiety to allow further functionalization. The compound 3 was prepared from 2 by conversion of the alkyne to a triazole group bearing an alkyl chain with an alcohol function. These three rhodamine derivatives exhibited similar electrochemical behaviors. Their mono-electronic reductions produced the corresponding radical species which were stable on the time-scale of cyclic voltammetry. Additional reduction of electrogenerated radicals produced unstable anions which underwent subsequent chemical reaction, most likely protonation. Based on cyclic voltammetry investigations, absorption and fluorescence spectroelectrochemistry were then performed on compounds 1, 2, 3 and their parent reduced radicals 1a, 2a, 3a. UV\textendashVis spectroelectrochemistry, combined with TD-DFT calculation, confirmed the formation of radicals upon mono-electronic reduction of starting rhodamines. Fluorescence spectroelectrochemistry showed that, contrary to their parent molecules, electrogenerated radicals were non-fluorescent. Electrochemical fluorescence extinction was successfully achieved with all studied compounds. Moreover, compound 1 underwent on/off switching between fluorescent and non-fluorescent states repeatedly. Also, recovery of fluorescence in compound 3 was observed, which open interesting opportunities for the development of versatile rhodamine-based probes. © 2017 The Authors}, keywords = {}, pubstate = {published}, tppubtype = {article} } Three rhodamine derivatives exhibiting electrofluorochromic properties were investigated by cyclic voltammetry and UV–Vis/fluorescence spectroelectrochemistry. Rhodamine 101 (Rh101, compound 1) was used as a reference model. In compound 2, the carboxylate anion of Rh101 was replaced by an alkyne moiety to allow further functionalization. The compound 3 was prepared from 2 by conversion of the alkyne to a triazole group bearing an alkyl chain with an alcohol function. These three rhodamine derivatives exhibited similar electrochemical behaviors. Their mono-electronic reductions produced the corresponding radical species which were stable on the time-scale of cyclic voltammetry. Additional reduction of electrogenerated radicals produced unstable anions which underwent subsequent chemical reaction, most likely protonation. Based on cyclic voltammetry investigations, absorption and fluorescence spectroelectrochemistry were then performed on compounds 1, 2, 3 and their parent reduced radicals 1a, 2a, 3a. UV–Vis spectroelectrochemistry, combined with TD-DFT calculation, confirmed the formation of radicals upon mono-electronic reduction of starting rhodamines. Fluorescence spectroelectrochemistry showed that, contrary to their parent molecules, electrogenerated radicals were non-fluorescent. Electrochemical fluorescence extinction was successfully achieved with all studied compounds. Moreover, compound 1 underwent on/off switching between fluorescent and non-fluorescent states repeatedly. Also, recovery of fluorescence in compound 3 was observed, which open interesting opportunities for the development of versatile rhodamine-based probes. © 2017 The Authors |
Inter-kingdom effect on epithelial cells of the N-Acyl homoserine lactone 3-oxo-C12:2, a major quorum-sensing molecule from gut microbiota Article de journal C Landman; J -P Grill; J -M Mallet; P Marteau; L Humbert; E L Balc’h; M -A Maubert; K Perez; W Chaara; L Brot; L Beaugerie; H Sokol; S Thenet; D Rainteau; P Seksik; E Quévrain PLoS ONE, 13 (8), 2018. @article{Landman:2018, title = {Inter-kingdom effect on epithelial cells of the N-Acyl homoserine lactone 3-oxo-C12:2, a major quorum-sensing molecule from gut microbiota}, author = {C Landman and J -P Grill and J -M Mallet and P Marteau and L Humbert and E L Balc’h and M -A Maubert and K Perez and W Chaara and L Brot and L Beaugerie and H Sokol and S Thenet and D Rainteau and P Seksik and E Qu\'{e}vrain}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85052807116&doi=10.1371%2fjournal.pone.0202587&partnerID=40&md5=ff949e3ec9730a2a172169cfa8e56815}, doi = {10.1371/journal.pone.0202587}, year = {2018}, date = {2018-01-01}, journal = {PLoS ONE}, volume = {13}, number = {8}, abstract = {Background and aims N-acyl homoserine lactones (AHLs), which are autoinducer quorum-sensing molecules involved in the bacterial communication network, also interact with eukaryotic cells. Searching for these molecules in the context of inflammatory bowel disease (IBD) is appealing. The aims of our study were to look for AHL molecules in faecal samples from healthy subjects (HS) and IBD patients to correlate AHL profiles with the microbiome and investigate the effect of AHLs of interest on epithelial cells. Methods Using mass spectrometry, we characterised AHL profiles in faecal samples from HS (n = 26) and IBD patients in remission (n = 24) and in flare (n = 25) and correlated the presence of AHLs of interest with gut microbiota composition obtained by real-time qPCR and 16S sequencing. We synthesised AHLs of interest to test the inflammatory response after IL1β stimulation and paracellular permeability on Caco-2 cells. Results We observed 14 different AHLs, among which one was prominent. This AHL corresponded to 3-oxo-C12:2 and was found significantly less frequently in IBD patients in flare (16%) and in remission (37.5%) versus HS (65.4%) (p = 0.001). The presence of 3-oxo-C12:2 was associated with significantly higher counts of Firmicutes, especially Faecalbacterium prausnitzii, and lower counts of Escherichia coli. In vitro, 3-oxo-C12:2 exerted an anti-inflammatory effect on Caco-2 cells. Interestingly, although 3-oxo-C12, the well-known AHL from Pseudomonas aeruginosa, increased paracellular permeability, 3-oxo-C12:2 did not. Conclusions We identified AHLs in the human gut microbiota and discovered a new and prominent AHL, 3-oxo-C12:2, which correlates with normobiosis and exerts a protective effect on gut epithelial cells. © 2018 Landman et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Background and aims N-acyl homoserine lactones (AHLs), which are autoinducer quorum-sensing molecules involved in the bacterial communication network, also interact with eukaryotic cells. Searching for these molecules in the context of inflammatory bowel disease (IBD) is appealing. The aims of our study were to look for AHL molecules in faecal samples from healthy subjects (HS) and IBD patients to correlate AHL profiles with the microbiome and investigate the effect of AHLs of interest on epithelial cells. Methods Using mass spectrometry, we characterised AHL profiles in faecal samples from HS (n = 26) and IBD patients in remission (n = 24) and in flare (n = 25) and correlated the presence of AHLs of interest with gut microbiota composition obtained by real-time qPCR and 16S sequencing. We synthesised AHLs of interest to test the inflammatory response after IL1β stimulation and paracellular permeability on Caco-2 cells. Results We observed 14 different AHLs, among which one was prominent. This AHL corresponded to 3-oxo-C12:2 and was found significantly less frequently in IBD patients in flare (16%) and in remission (37.5%) versus HS (65.4%) (p = 0.001). The presence of 3-oxo-C12:2 was associated with significantly higher counts of Firmicutes, especially Faecalbacterium prausnitzii, and lower counts of Escherichia coli. In vitro, 3-oxo-C12:2 exerted an anti-inflammatory effect on Caco-2 cells. Interestingly, although 3-oxo-C12, the well-known AHL from Pseudomonas aeruginosa, increased paracellular permeability, 3-oxo-C12:2 did not. Conclusions We identified AHLs in the human gut microbiota and discovered a new and prominent AHL, 3-oxo-C12:2, which correlates with normobiosis and exerts a protective effect on gut epithelial cells. © 2018 Landman et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
2017 |
Role of Fluoride Ions in Palladium-Catalyzed Cross-Coupling Reactions Article de journal L Grimaud; A Jutand Synthesis (Germany), 49 (6), p. 1182–1189, 2017. @article{Grimaud:2017, title = {Role of Fluoride Ions in Palladium-Catalyzed Cross-Coupling Reactions}, author = {L Grimaud and A Jutand}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84995394412&doi=10.1055%2fs-0036-1588648&partnerID=40&md5=6381ca828d4aed1d86041894aa7b98e0}, doi = {10.1055/s-0036-1588648}, year = {2017}, date = {2017-01-01}, journal = {Synthesis (Germany)}, volume = {49}, number = {6}, pages = {1182--1189}, abstract = {Fluoride ions are known to promote Suzuki-Miyaura, Hiyama, and Stille reactions [cross-coupling between aryl halides ArX and nucleophiles Ar′B(OH)2, Ar′Si(OMe)3, and Ar′SnBu3, respectively], where they exert a similar triple role: (1) They favor transmetalation by formation of trans-ArPdFL2 (L = PPh3) complexes that react with the nucleophiles in contrast to trans-ArPdXL2. (2) They catalyze the reductive elimination from trans-ArPdAr′L2 generated in the transmetalation. (3) The final role is negative, by formation of unreactive anionic species [Ar′BF(OH)2]-, [Ar′SiF(OMe)3]-, or [Ar′SnFBu3]-, respectively. Consequently the rate of the rate-determining transmetalation is controlled by the concentration ratio [F-]/[nucleophile] which must be less or close to one to ensure fast transmetalation. 1 Introduction 2 Reaction of Fluoride Ions with ArPdXL2 Complexes 3 The Triple Role of Fluoride Ions in Suzuki-Miyaura Reactions 4 The Triple Role of Fluoride Ions in Hiyama Reactions 5 The Triple Role of Fluoride Ions in Stille Reactions 6 Conclusion. © 2017 Georg Thieme Verlag Stuttgart. New York.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Fluoride ions are known to promote Suzuki-Miyaura, Hiyama, and Stille reactions [cross-coupling between aryl halides ArX and nucleophiles Ar′B(OH)2, Ar′Si(OMe)3, and Ar′SnBu3, respectively], where they exert a similar triple role: (1) They favor transmetalation by formation of trans-ArPdFL2 (L = PPh3) complexes that react with the nucleophiles in contrast to trans-ArPdXL2. (2) They catalyze the reductive elimination from trans-ArPdAr′L2 generated in the transmetalation. (3) The final role is negative, by formation of unreactive anionic species [Ar′BF(OH)2]-, [Ar′SiF(OMe)3]-, or [Ar′SnFBu3]-, respectively. Consequently the rate of the rate-determining transmetalation is controlled by the concentration ratio [F-]/[nucleophile] which must be less or close to one to ensure fast transmetalation. 1 Introduction 2 Reaction of Fluoride Ions with ArPdXL2 Complexes 3 The Triple Role of Fluoride Ions in Suzuki-Miyaura Reactions 4 The Triple Role of Fluoride Ions in Hiyama Reactions 5 The Triple Role of Fluoride Ions in Stille Reactions 6 Conclusion. © 2017 Georg Thieme Verlag Stuttgart. New York. |
Supramolecular Chitosan Micro-Platelets Synergistically Enhance Anti-Candida albicans Activity of Amphotericin B Using an Immunocompetent Murine Model Article de journal T Grisin; C Bories; M Bombardi; P M Loiseau; V Rouffiac; A Solgadi; J -M Mallet; G Ponchel; K Bouchemal Pharmaceutical Research, 34 (5), p. 1067–1082, 2017. @article{Grisin:2017, title = {Supramolecular Chitosan Micro-Platelets Synergistically Enhance Anti-Candida albicans Activity of Amphotericin B Using an Immunocompetent Murine Model}, author = {T Grisin and C Bories and M Bombardi and P M Loiseau and V Rouffiac and A Solgadi and J -M Mallet and G Ponchel and K Bouchemal}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85011710508&doi=10.1007%2fs11095-017-2117-3&partnerID=40&md5=f9437388887f80d0478b2a95b7fd46ad}, doi = {10.1007/s11095-017-2117-3}, year = {2017}, date = {2017-01-01}, journal = {Pharmaceutical Research}, volume = {34}, number = {5}, pages = {1067--1082}, abstract = {Purpose: The aim of this work is to design new chitosan conjugates able to self-organize in aqueous solution in the form of micrometer-size platelets. When mixed with amphotericin B deoxycholate (AmB-DOC), micro-platelets act as a drug booster allowing further improvement in AmB-DOC anti-Candida albicans activity. Methods: Micro-platelets were obtained by mixing oleoyl chitosan and α-cyclodextrin in water. The formulation is specifically-engineered for mucosal application by dispersing chitosan micro-platelets into thermosensitive pluronic® F127 20 wt% hydrogel. Results: The formulation completely cured C. albicans vaginal infection in mice and had a superior activity in comparison with AmB-DOC without addition of chitosan micro-platelets. In vitro studies showed that the platelets significantly enhance AmB-DOC antifungal activity since the IC50 and the MIC90 decrease 4.5 and 4.8-times. Calculation of fractional inhibitory concentration index (FICI = 0.198) showed that chitosan micro-platelets act in a synergistic way with AmB-DOC against C. albicans. No synergy is found between spherical nanoparticles composed poly(isobutylcyanoacrylate)/chitosan and AmB-DOC. Conclusion: These results demonstrate for the first time the ability of flattened chitosan micro-platelets to have synergistic activity with AmB-DOC against C. albicans candidiasis and highlight the importance of rheological and mucoadhesive behaviors of hydrogels in the efficacy of the treatment. © 2017, Springer Science+Business Media New York.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Purpose: The aim of this work is to design new chitosan conjugates able to self-organize in aqueous solution in the form of micrometer-size platelets. When mixed with amphotericin B deoxycholate (AmB-DOC), micro-platelets act as a drug booster allowing further improvement in AmB-DOC anti-Candida albicans activity. Methods: Micro-platelets were obtained by mixing oleoyl chitosan and α-cyclodextrin in water. The formulation is specifically-engineered for mucosal application by dispersing chitosan micro-platelets into thermosensitive pluronic® F127 20 wt% hydrogel. Results: The formulation completely cured C. albicans vaginal infection in mice and had a superior activity in comparison with AmB-DOC without addition of chitosan micro-platelets. In vitro studies showed that the platelets significantly enhance AmB-DOC antifungal activity since the IC50 and the MIC90 decrease 4.5 and 4.8-times. Calculation of fractional inhibitory concentration index (FICI = 0.198) showed that chitosan micro-platelets act in a synergistic way with AmB-DOC against C. albicans. No synergy is found between spherical nanoparticles composed poly(isobutylcyanoacrylate)/chitosan and AmB-DOC. Conclusion: These results demonstrate for the first time the ability of flattened chitosan micro-platelets to have synergistic activity with AmB-DOC against C. albicans candidiasis and highlight the importance of rheological and mucoadhesive behaviors of hydrogels in the efficacy of the treatment. © 2017, Springer Science+Business Media New York. |
The inhibition of tyrosinase by some aryl butenes: A desired activity or a side effect to avoid Article de journal E Ketata; A Neifar; W Mihoubi; P Pigeon; H Gouzi; J -M Mallet; S Top; G K Gupta; G Jaouen; A Gargouri; M El Arbi Journal of Organometallic Chemistry, 848 , p. 133–141, 2017. @article{Ketata:2017, title = {The inhibition of tyrosinase by some aryl butenes: A desired activity or a side effect to avoid}, author = {E Ketata and A Neifar and W Mihoubi and P Pigeon and H Gouzi and J -M Mallet and S Top and G K Gupta and G Jaouen and A Gargouri and M El Arbi}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85026674207&doi=10.1016%2fj.jorganchem.2017.07.031&partnerID=40&md5=10c0783ea7acb8f6dbd54dbb19c427ca}, doi = {10.1016/j.jorganchem.2017.07.031}, year = {2017}, date = {2017-01-01}, journal = {Journal of Organometallic Chemistry}, volume = {848}, pages = {133--141}, abstract = {Inhibitory effects on the monophenolase activity of tyrosinase of some aryl butenes derivatives, having moderate to excellent inhibitory activity on MDA-MB-231 breast cancer cell, have been examined. The results show that the substitution of the phenol group by other functional moieties or its removal (unsubstituted phenyl) makes the loss of the tyrosinase inhibition effect of the compounds. Interestingly, the protection of the phenol group of the compounds by a sugar (glucose) led to the loss of the inhibitory activity on tyrosinase but maintained the antitumor activity. The tyrosinase inhibiting potential is considered as a side effect as it leads to depigmentation. Some ferrocenyl aryl butene compounds behave as reversible inhibitors of tyrosinase and kinetic analyses showed that the inhibition type of three derivatives compounds was competitive and another compound was non-competitive. Moreover, the compounds 8 and 19 were found to be the most potent inhibitors of tyrosinase activity among these compounds with IC50 values of 20 and 25 μM, respectively. However, compound 18 was the most effective compound against MDA-MB-231 tumoral cells with an IC50 value of 0.86 μM; it could be used as an anticancer drug without interfering with tyrosinase activity and pigmentation process. Conclusively, if some compounds are excellent candidates for cosmetics, others showed strong antitumor activity without depigmentation side effect. © 2017 Elsevier B.V.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Inhibitory effects on the monophenolase activity of tyrosinase of some aryl butenes derivatives, having moderate to excellent inhibitory activity on MDA-MB-231 breast cancer cell, have been examined. The results show that the substitution of the phenol group by other functional moieties or its removal (unsubstituted phenyl) makes the loss of the tyrosinase inhibition effect of the compounds. Interestingly, the protection of the phenol group of the compounds by a sugar (glucose) led to the loss of the inhibitory activity on tyrosinase but maintained the antitumor activity. The tyrosinase inhibiting potential is considered as a side effect as it leads to depigmentation. Some ferrocenyl aryl butene compounds behave as reversible inhibitors of tyrosinase and kinetic analyses showed that the inhibition type of three derivatives compounds was competitive and another compound was non-competitive. Moreover, the compounds 8 and 19 were found to be the most potent inhibitors of tyrosinase activity among these compounds with IC50 values of 20 and 25 μM, respectively. However, compound 18 was the most effective compound against MDA-MB-231 tumoral cells with an IC50 value of 0.86 μM; it could be used as an anticancer drug without interfering with tyrosinase activity and pigmentation process. Conclusively, if some compounds are excellent candidates for cosmetics, others showed strong antitumor activity without depigmentation side effect. © 2017 Elsevier B.V. |
Dimerization of the fungal defense lectin CCL2 is essential for its toxicity against nematodes Article de journal S Bleuler-Martinez; K Stutz; R Sieber; M Collot; J -M Mallet; M Hengartner; M Schubert; A Varrot; M Künzler Glycobiology, 27 (5), p. 486–500, 2017. @article{Bleuler-Martinez:2017, title = {Dimerization of the fungal defense lectin CCL2 is essential for its toxicity against nematodes}, author = {S Bleuler-Martinez and K Stutz and R Sieber and M Collot and J -M Mallet and M Hengartner and M Schubert and A Varrot and M K\"{u}nzler}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85019108275&doi=10.1093%2fglycob%2fcww113&partnerID=40&md5=c1e6a86d1b5f5865f623bd1236f3fcbc}, doi = {10.1093/glycob/cww113}, year = {2017}, date = {2017-01-01}, journal = {Glycobiology}, volume = {27}, number = {5}, pages = {486--500}, abstract = {Lectins are used as defense effector proteins against predators, parasites and pathogens by animal, plant and fungal innate defense systems. These proteins bind to specific glycoepitopes on the cell surfaces and thereby interfere with the proper cellular functions of the various antagonists. The exact cellular toxicity mechanism is in many cases unclear. Lectin CCL2 of the mushroom Coprinopsis cinerea was previously shown to be toxic for Caenorhabditis elegans and Drosophila melanogaster. This toxicity is dependent on a single, high-affinity binding site for the trisaccharide GlcNAc(Fuca1,3)β1,4GlcNAc, which is a hallmark of nematode and insect N-glycan cores. The carbohydrate-binding site is located at an unusual position on the protein surface when compared to other β-trefoil lectins. Here, we show that CCL2 forms a compact dimer in solution and in crystals. Substitution of two amino acid residues at the dimer interface, R18A and F133A, interfered with dimerization of CCL2 and reduced toxicity but left carbohydrate-binding unaffected. These results, together with the positioning of the two carbohydrate-binding sites on the surface of the protein dimer, suggest that crosslinking of N-glycoproteins on the surface of intestinal cells of invertebrates is a crucial step in the mechanism of CCL2-mediated toxicity. Comparisons of the number and positioning of carbohydrate-binding sites among different dimerizing fungal β-trefoil lectins revealed a considerable variability in the carbohydrate-binding patterns of these proteins, which are likely to correlate with their respective functions. © 2016 The Author.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Lectins are used as defense effector proteins against predators, parasites and pathogens by animal, plant and fungal innate defense systems. These proteins bind to specific glycoepitopes on the cell surfaces and thereby interfere with the proper cellular functions of the various antagonists. The exact cellular toxicity mechanism is in many cases unclear. Lectin CCL2 of the mushroom Coprinopsis cinerea was previously shown to be toxic for Caenorhabditis elegans and Drosophila melanogaster. This toxicity is dependent on a single, high-affinity binding site for the trisaccharide GlcNAc(Fuca1,3)β1,4GlcNAc, which is a hallmark of nematode and insect N-glycan cores. The carbohydrate-binding site is located at an unusual position on the protein surface when compared to other β-trefoil lectins. Here, we show that CCL2 forms a compact dimer in solution and in crystals. Substitution of two amino acid residues at the dimer interface, R18A and F133A, interfered with dimerization of CCL2 and reduced toxicity but left carbohydrate-binding unaffected. These results, together with the positioning of the two carbohydrate-binding sites on the surface of the protein dimer, suggest that crosslinking of N-glycoproteins on the surface of intestinal cells of invertebrates is a crucial step in the mechanism of CCL2-mediated toxicity. Comparisons of the number and positioning of carbohydrate-binding sites among different dimerizing fungal β-trefoil lectins revealed a considerable variability in the carbohydrate-binding patterns of these proteins, which are likely to correlate with their respective functions. © 2016 The Author. |
Toward Complete Sequence Flexibility of Nucleic Acid Base Analogue FRET Article de journal Moa S Wranne; Anders Foller Füchtbauer; Blaise Dumat; Mattias Bood; Afaf H El-Sagheer; Tom Brown; Henrik Gradén; Morten Grøtli; Marcus L Wilhelmsson Journal of the American Chemical Society, 139 (27), p. 9271-9280, 2017. @article{Wranne:2017, title = {Toward Complete Sequence Flexibility of Nucleic Acid Base Analogue FRET}, author = {Moa S Wranne and Anders Foller F\"{u}chtbauer and Blaise Dumat and Mattias Bood and Afaf H {El-Sagheer} and Tom Brown and Henrik Grad\'{e}n and Morten Gr\otli and Marcus L Wilhelmsson}, doi = {10.1021/jacs.7b04517}, year = {2017}, date = {2017-01-01}, journal = {Journal of the American Chemical Society}, volume = {139}, number = {27}, pages = {9271-9280}, abstract = {F\"{o}rster resonance energy transfer (FRET) using fluorescent base analogues is a powerful means of obtaining high-resolution nucleic acid structure and dynamics information that favorably complements techniques such as NMR and X-ray crystallography. Here, we expand the base\textendashbase FRET repertoire with an adenine analogue FRET-pair. Phosphoramidite-protected quadracyclic 2$'$-deoxyadenosine analogues qAN1 (donor) and qAnitro (acceptor) were synthesized and incorporated into DNA by a generic, reliable, and high-yielding route, and both constitute excellent adenine analogues. The donor, qAN1, has quantum yields reaching 21% and 11% in single- and double-strands, respectively. To the best of our knowledge, this results in the highest average brightness of an adenine analogue inside DNA. Its potent emissive features overlap well with the absorption of qAnitro and thus enable accurate FRET-measurements over more than one turn of B-DNA. As we have shown previously for our cytosine analogue FRET-pair, FRET between qAN1...}, keywords = {}, pubstate = {published}, tppubtype = {article} } Förster resonance energy transfer (FRET) using fluorescent base analogues is a powerful means of obtaining high-resolution nucleic acid structure and dynamics information that favorably complements techniques such as NMR and X-ray crystallography. Here, we expand the base–base FRET repertoire with an adenine analogue FRET-pair. Phosphoramidite-protected quadracyclic 2$'$-deoxyadenosine analogues qAN1 (donor) and qAnitro (acceptor) were synthesized and incorporated into DNA by a generic, reliable, and high-yielding route, and both constitute excellent adenine analogues. The donor, qAN1, has quantum yields reaching 21% and 11% in single- and double-strands, respectively. To the best of our knowledge, this results in the highest average brightness of an adenine analogue inside DNA. Its potent emissive features overlap well with the absorption of qAnitro and thus enable accurate FRET-measurements over more than one turn of B-DNA. As we have shown previously for our cytosine analogue FRET-pair, FRET between qAN1... |
Ugi-Smiles Couplings of Purine Derivatives Article de journal A B Abdessalem; R Abderrahim; A Dos Santos; L El Kaïm; L Grimaud Synlett, 28 (6), p. 691–694, 2017. @article{Abdessalem:2017, title = {Ugi-Smiles Couplings of Purine Derivatives}, author = {A B Abdessalem and R Abderrahim and A Dos Santos and L El Ka\"{i}m and L Grimaud}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85001574774&doi=10.1055%2fs-0036-1588117&partnerID=40&md5=9a1f6e5cb8ef3787a1e69a78dc45fd26}, doi = {10.1055/s-0036-1588117}, year = {2017}, date = {2017-01-01}, journal = {Synlett}, volume = {28}, number = {6}, pages = {691--694}, abstract = {Purines may be involved in Ugi-Smiles coupling as shown by the successful formation of thiocarboxamide derivatives from 6-mercaptopurine. This multicomponent coupling affords a very straightforward access to functionalized adenine derivatives, which are widely represented among natural products of medicinal interest. © Georg Thieme VerlagStuttgart · New York.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Purines may be involved in Ugi-Smiles coupling as shown by the successful formation of thiocarboxamide derivatives from 6-mercaptopurine. This multicomponent coupling affords a very straightforward access to functionalized adenine derivatives, which are widely represented among natural products of medicinal interest. © Georg Thieme VerlagStuttgart · New York. |
Stereoselective access to trisubstituted fluorinated alkenyl thioethers Article de journal I Fabre; T Poisson; X Pannecoucke; I Gillaizeau; I Ciofini; L Grimaud Catalysis Science and Technology, 7 (9), p. 1921–1927, 2017. @article{Fabre:2017, title = {Stereoselective access to trisubstituted fluorinated alkenyl thioethers}, author = {I Fabre and T Poisson and X Pannecoucke and I Gillaizeau and I Ciofini and L Grimaud}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85022209374&doi=10.1039%2fc7cy00076f&partnerID=40&md5=cf5efa97674f64ae4f3a3c3f98096ec0}, doi = {10.1039/c7cy00076f}, year = {2017}, date = {2017-01-01}, journal = {Catalysis Science and Technology}, volume = {7}, number = {9}, pages = {1921--1927}, abstract = {We report the first copper-catalyzed olefinic ethoxy carbonyl difluoromethylation of alkenyl thioethers via direct C-H bond functionalization using BrCF2COOEt. The developed methodology allows the preparation of trisubstituted olefins with a controlled stereochemistry. A mechanistic study is reported and a radical mechanism is revealed. © 2017 The Royal Society of Chemistry.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report the first copper-catalyzed olefinic ethoxy carbonyl difluoromethylation of alkenyl thioethers via direct C-H bond functionalization using BrCF2COOEt. The developed methodology allows the preparation of trisubstituted olefins with a controlled stereochemistry. A mechanistic study is reported and a radical mechanism is revealed. © 2017 The Royal Society of Chemistry. |
N-N bond formation in Ugi processes: from nitric acid to libraries of nitramines Article de journal V Mercalli; A Nyadanu; M Cordier; G C Tron; L Grimaud; L El Kaim Chemical Communications, 53 (13), p. 2118–2121, 2017. @article{Mercalli:2017, title = {N-N bond formation in Ugi processes: from nitric acid to libraries of nitramines}, author = {V Mercalli and A Nyadanu and M Cordier and G C Tron and L Grimaud and L El Kaim}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85012195472&doi=10.1039%2fc6cc10288c&partnerID=40&md5=74bc350d7ed83c98b00d926bbb161b68}, doi = {10.1039/c6cc10288c}, year = {2017}, date = {2017-01-01}, journal = {Chemical Communications}, volume = {53}, number = {13}, pages = {2118--2121}, abstract = {The Ugi reaction has drawn considerable attention over the years leading to numerous libraries of heterocycles and various extensions changing the nature of the components of the coupling. We report here the use of nitric acid as carboxylic acids surrogates, displaying the first aminative Ugi-type reaction leading to nitramines. © The Royal Society of Chemistry.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The Ugi reaction has drawn considerable attention over the years leading to numerous libraries of heterocycles and various extensions changing the nature of the components of the coupling. We report here the use of nitric acid as carboxylic acids surrogates, displaying the first aminative Ugi-type reaction leading to nitramines. © The Royal Society of Chemistry. |
A Dual Functional Electroactive and Fluorescent Probe for Coupled Measurements of Vesicular Exocytosis with High Spatial and Temporal Resolution Article de journal X Liu; A Savy; S Maurin; L Grimaud; F Darchen; D Quinton; E Labbé; O Buriez; J Delacotte; F Lemaître; M Guille-Collignon Angewandte Chemie - International Edition, 56 (9), p. 2366–2370, 2017. @article{Liu:2017a, title = {A Dual Functional Electroactive and Fluorescent Probe for Coupled Measurements of Vesicular Exocytosis with High Spatial and Temporal Resolution}, author = {X Liu and A Savy and S Maurin and L Grimaud and F Darchen and D Quinton and E Labb\'{e} and O Buriez and J Delacotte and F Lema\^{i}tre and M Guille-Collignon}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85010696856&doi=10.1002%2fanie.201611145&partnerID=40&md5=a51767157166d7f185f0195a28b347b8}, doi = {10.1002/anie.201611145}, year = {2017}, date = {2017-01-01}, journal = {Angewandte Chemie - International Edition}, volume = {56}, number = {9}, pages = {2366--2370}, abstract = {In this work, Fluorescent False Neurotransmitter 102 (FFN102), a synthesized analogue of biogenic neurotransmitters, was demonstrated to show both pH-dependent fluorescence and electroactivity. To study secretory behaviors at the single-vesicle level, FFN102 was employed as a new fluorescent/electroactive dual probe in a coupled technique (amperometry and total internal reflection fluorescence microscopy (TIRFM)). We used N13 cells, a stable clone of BON cells, to specifically accumulate FFN102 into their secretory vesicles, and then optical and electrochemical measurements of vesicular exocytosis were experimentally achieved by using indium tin oxide (ITO) transparent electrodes. Upon stimulation, FFN102 started to diffuse out from the acidic intravesicular microenvironment to the neutral extracellular space, leading to fluorescent emissions and to the electrochemical oxidation signals that were simultaneously collected from the ITO electrode surface. The correlation of fluorescence and amperometric signals resulting from the FFN102 probe allows real-time monitoring of single exocytotic events with both high spatial and temporal resolution. This work opens new possibilities in the investigation of exocytotic mechanisms. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this work, Fluorescent False Neurotransmitter 102 (FFN102), a synthesized analogue of biogenic neurotransmitters, was demonstrated to show both pH-dependent fluorescence and electroactivity. To study secretory behaviors at the single-vesicle level, FFN102 was employed as a new fluorescent/electroactive dual probe in a coupled technique (amperometry and total internal reflection fluorescence microscopy (TIRFM)). We used N13 cells, a stable clone of BON cells, to specifically accumulate FFN102 into their secretory vesicles, and then optical and electrochemical measurements of vesicular exocytosis were experimentally achieved by using indium tin oxide (ITO) transparent electrodes. Upon stimulation, FFN102 started to diffuse out from the acidic intravesicular microenvironment to the neutral extracellular space, leading to fluorescent emissions and to the electrochemical oxidation signals that were simultaneously collected from the ITO electrode surface. The correlation of fluorescence and amperometric signals resulting from the FFN102 probe allows real-time monitoring of single exocytotic events with both high spatial and temporal resolution. This work opens new possibilities in the investigation of exocytotic mechanisms. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim |
Copper-Catalyzed Hydroamination of Allenes: From Mechanistic Understanding to Methodology Development Article de journal L A Perego; R Blieck; A Groué; F Monnier; M Taillefer; I Ciofini; L Grimaud ACS Catalysis, 7 (7), p. 4253–4264, 2017. @article{Perego:2017a, title = {Copper-Catalyzed Hydroamination of Allenes: From Mechanistic Understanding to Methodology Development}, author = {L A Perego and R Blieck and A Grou\'{e} and F Monnier and M Taillefer and I Ciofini and L Grimaud}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85024925525&doi=10.1021%2facscatal.7b00911&partnerID=40&md5=5f3d3918b036996672327478a85efb5a}, doi = {10.1021/acscatal.7b00911}, year = {2017}, date = {2017-01-01}, journal = {ACS Catalysis}, volume = {7}, number = {7}, pages = {4253--4264}, abstract = {Experimental and theoretical mechanistic studies on the Cu(OTf)2-catalyzed hydroamination reaction of terminal allenes with secondary amines reveal that in situ generated cationic Cu(I) is the catalytically active species and explain the observed regio- and stereoselectivity for the unbranched E product. Insight into the structure of the relevant transition states allowed the generalization of this methodology to allenamides and N-allenylcarbamates under unprecedentedly mild and functional-group-tolerant conditions. Chelation effects by the amide oxygen in addition to electronic effects explain the high innate reactivity of this class of substrates. © 2017 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Experimental and theoretical mechanistic studies on the Cu(OTf)2-catalyzed hydroamination reaction of terminal allenes with secondary amines reveal that in situ generated cationic Cu(I) is the catalytically active species and explain the observed regio- and stereoselectivity for the unbranched E product. Insight into the structure of the relevant transition states allowed the generalization of this methodology to allenamides and N-allenylcarbamates under unprecedentedly mild and functional-group-tolerant conditions. Chelation effects by the amide oxygen in addition to electronic effects explain the high innate reactivity of this class of substrates. © 2017 American Chemical Society. |
Copper-Catalyzed Hydroamination of N-Allenylazoles: Access to Amino-Substituted N-Vinylazoles Article de journal L A Perego; R Blieck; J Michel; I Ciofini; L Grimaud; M Taillefer; F Monnier Advanced Synthesis and Catalysis, 359 (24), p. 4388–4392, 2017. @article{Perego:2017, title = {Copper-Catalyzed Hydroamination of N-Allenylazoles: Access to Amino-Substituted N-Vinylazoles}, author = {L A Perego and R Blieck and J Michel and I Ciofini and L Grimaud and M Taillefer and F Monnier}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85031504221&doi=10.1002%2fadsc.201700965&partnerID=40&md5=b6253215a708de34ef84f1990bc71129}, doi = {10.1002/adsc.201700965}, year = {2017}, date = {2017-01-01}, journal = {Advanced Synthesis and Catalysis}, volume = {359}, number = {24}, pages = {4388--4392}, abstract = {Building on mechanistic studies, the innate capability of azoles to act as a directing group has been exploited to design an efficient and simple procedure for the hydroamination of N-allenylazoles with secondary amines. The reaction proceeds under mild conditions by copper(I) catalysis yielding the corresponding original linear E allylic amines with total regio- and stereoselectivity. Density Functional Theory (DFT) calculations offer a mechanistic explanation of the significantly higher reactivity of N-allenyl-(1,2)-azoles compared to their 1,3-analogues as a result of the reaction-enhancing coordination of the pyridine-like nitrogen to the copper center. (Figure presented.). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim}, keywords = {}, pubstate = {published}, tppubtype = {article} } Building on mechanistic studies, the innate capability of azoles to act as a directing group has been exploited to design an efficient and simple procedure for the hydroamination of N-allenylazoles with secondary amines. The reaction proceeds under mild conditions by copper(I) catalysis yielding the corresponding original linear E allylic amines with total regio- and stereoselectivity. Density Functional Theory (DFT) calculations offer a mechanistic explanation of the significantly higher reactivity of N-allenyl-(1,2)-azoles compared to their 1,3-analogues as a result of the reaction-enhancing coordination of the pyridine-like nitrogen to the copper center. (Figure presented.). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim |