The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Renzo Luisi - One of the best experts on this subject based on the ideXlab platform.
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Azetidine-Borane Complexes: Synthesis, Reactivity, and Stereoselective Functionalization.
The Journal of organic chemistry, 2018Co-Authors: Michael Andresini, Leonardo Degennaro, Sonia De Angelis, Antonella Uricchio, Angelica Visaggio, Giuseppe Romanazzi, Fulvio Ciriaco, Nicola Corriero, Renzo LuisiAbstract:The present study reports, for the first time, the synthesis and structural features of Azetidine–borane complexes, as well as their reactivity in lithiation reactions. A temperature-dependent stereoselectivity has been disclosed in the reaction of borane with N-alkyl-2-arylAzetidines, allowing for a stereoselective preparation of Azetidine–borane complexes 2 and 3. A regioselective hydrogen/lithium permutation, at the benzylic position, was observed in lithiation reactions of complexes possessing a syn relationship, between the ring proton and the BH3 group. In contrast, scarce or no reactivity was noticed in complexes lacking such a stereochemical requirement. The configurational stability of the lithiated intermediates has also been investigated, in order to shed some light on the stereoselectivity of the lithiation/electrophile trapping sequence. Calculations helped in supporting experimental observations, concerning structure and reactivity of these Azetidine–borane complexes. Data suggest that the B...
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Use of Azetidine scaffolds in stereoselective transformations (microreview)
Chemistry of Heterocyclic Compounds, 2018Co-Authors: Renzo Luisi, Leonardo DegennaroAbstract:Noteworthy stereoselective approaches toward the synthesis of densely substituted Azetidines are reported. This microreview covers a selection of the latest efficient methods for the functionalization of Azetidine cores by metalation, C–H activation, radical or biocatalytic processes, as well as nonclassical and large-scale preparative procedures.
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Azetidine–Borane Complexes: Synthesis, Reactivity, and Stereoselective Functionalization
2018Co-Authors: Michael Andresini, Leonardo Degennaro, Sonia De Angelis, Antonella Uricchio, Angelica Visaggio, Giuseppe Romanazzi, Fulvio Ciriaco, Nicola Corriero, Renzo LuisiAbstract:The present study reports, for the first time, the synthesis and structural features of Azetidine–borane complexes, as well as their reactivity in lithiation reactions. A temperature-dependent stereoselectivity has been disclosed in the reaction of borane with N-alkyl-2-arylAzetidines, allowing for a stereoselective preparation of Azetidine–borane complexes 2 and 3. A regioselective hydrogen/lithium permutation, at the benzylic position, was observed in lithiation reactions of complexes possessing a syn relationship, between the ring proton and the BH3 group. In contrast, scarce or no reactivity was noticed in complexes lacking such a stereochemical requirement. The configurational stability of the lithiated intermediates has also been investigated, in order to shed some light on the stereoselectivity of the lithiation/electrophile trapping sequence. Calculations helped in supporting experimental observations, concerning structure and reactivity of these Azetidine–borane complexes. Data suggest that the BH3 group could promote the lithiation reaction likely by an electrostatic complex induced proximity effect. Interestingly, a new synthetic strategy for the synthesis of N-alkyl-2,2-disubstituted Azetidines has been developed
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Recent advances in the chemistry of metallated Azetidines
Organic & biomolecular chemistry, 2016Co-Authors: Daniele Antermite, Leonardo Degennaro, Renzo LuisiAbstract:The almost unexplored four-membered heterocycles Azetidines, represent a particularly interesting class of molecules, among the family of saturated nitrogen heterocycles. Although often challenging to synthesize, substituted Azetidines strongly attract chemists because of their importance in catalysis, stereoselective synthesis and medicinal chemistry. This review aims to give a brief summary of modern developments in direct metal-based functionalization of the Azetidine ring, focusing on the regio- and stereoselectivity of these reactions, as well as on some useful synthetic applications. It will be highlighted, in particular, how an interplay of factors such as structure, substitutions at both nitrogen and carbon atoms and coordinative phenomena deeply influence the reactivity of the corresponding metallated species, paving the way for easy planning a site-selective functionalization of Azetidines.
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Easy access to constrained peptidomimetics and 2,2-disubstituted Azetidines by the unexpected reactivity profile of α-lithiated N-Boc-Azetidines
Chemical communications (Cambridge England), 2015Co-Authors: Giovanna Parisi, Leonardo Degennaro, Giuseppe Romanazzi, Emanuela Capitanelli, Antonella Pierro, Guy J. Clarkson, Renzo LuisiAbstract:The reactivity profile of lithiated N-Boc-2-arylAzetidines has been investigated filling a gap in the chemistry of this class of four-membered heterocycles. Two unexpected and unprecedented results have been observed: an “ortho-effect” accounting for the regioselective functionalization of the Azetidine ring, and self-condensation leading to new and interesting Azetidine-based peptidomimetics.
Katy Jeannot - One of the best experts on this subject based on the ideXlab platform.
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Azetidine-Containing Alkaloids Produced by a Quorum-Sensing Regulated Nonribosomal Peptide Synthetase Pathway in Pseudomonas aeruginosa
Angewandte Chemie International Edition, 2019Co-Authors: Zhilai Hong, Arnaud Bolard, Caroline Giraud, Sébastien Prevost, Grégory Genta-jouve, Christiane Deregnaucourt, Susanne Häussler, Katy JeannotAbstract:Pseudomonas aeruginosa displays an impressive metabolic versatility, which ensures its survival in diverse environments. Reported herein is the identification of rare Azetidine-containing alkaloids from P. aeruginosa PAO1, termed azetidomonamides, which are derived from a conserved, quorum-sensing regulated nonribosomal peptide synthetase (NRPS) pathway. Biosynthesis of the Azetidine motif has been elucidated by gene inactivation, feeding experiments, and biochemical characterization in vitro, which involves a new S-adenosylmethionine-dependent enzyme to produce Azetidine 2-carboxylic acid as an unusual building block of NRPS. The mutants of P. aeruginosa unable to produce azetidomonamides had an advantage in growth at high cell density in vitro and displayed rapid virulence in Galleria mellonella model, inferring functional roles of azetidomonamides in the host adaptation. This work opens the avenue to study the biological functions of azetidomonamides and related compounds in pathogenic and environmental bacteria.
François Couty - One of the best experts on this subject based on the ideXlab platform.
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Competitive Ring Expansion of Azetidines into Pyrrolidines and/or Azepanes
The Journal of organic chemistry, 2016Co-Authors: Bruno Drouillat, Igor V. Dorogan, Mikhail E. Kletskii, Oleg N. Burov, François CoutyAbstract:Azetidines fitted with a 3-hydroxypropyl side chain at the 2-position undergo intramolecular N-alkylation after activation of the primary alcohol, and the produced 1-azonia-bicyclo[3.2.0]heptane is opened by different nucleophiles (cyanide, azide, or acetate anions) to produce mixtures of ring expanded pyrrolidines and azepanes, or a unique type of compound. Distribution of produced five- or seven-membered rings depends on the substitution pattern on the Azetidine ring and on its side chain, together with the nature of the nucleophile used in the expansion process. Observed regioselectivities for nucleophilic opening are rationalized by quantum mechanical DFT calculations and are in good agreement with experimental results.
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Reaction of N-alkyl Azetidines with triphosgene
Tetrahedron Letters, 2015Co-Authors: Laurence Menguy, Bruno Drouillat, François CoutyAbstract:Abstract N-Alkyl Azetidines react with triphosgene (BTC) following two possible pathways: N-alkyl ring scission or ring cleavage, to give cyclic or acyclic N-carbamoyl chlorides. Predominance of one pathway over the other is governed by the nature of the substituents on the Azetidine ring and on the nitrogen atom as well as by the relative stereochemistry of the ring substituents, and is examined in detail. Some Azetidines were identified for their privileged reaction pathway, leading to new functionalized building blocks that were further elaborated into five- or six-membered urea or into azetidinic urea.
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Ring Expansion of 2-(1-Hydroxyalkyl)Azetidines to 4-(2-Chloroethyl)oxazolidinones
European Journal of Organic Chemistry, 2010Co-Authors: François Couty, Bruno Drouillat, Frédéric LeméeAbstract:2-(1-Hydroxyalkyl)Azetidines react with bis(trichloromethyl) carbonate (BTC) after basic treatment to afford 4-(2-chloroethyl)oxazolidinones. The scope of this rearrangement was examined in detail and its efficiency was shown to depend on the class of the reacting alcohol and on the substitution pattern on the Azetidine ring.
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Reaction of Azetidines with chloroformates.
Organic letters, 2006Co-Authors: Monica Vargas-sanchez, François Couty, Sami Lakhdar, Gwilherm EvanoAbstract:The reaction of an Azetidine with a chloroformate can give either the dealkylated heterocycle or the ring-opened product (γ-chloroamine), which can further cyclize to the oxazinanone. A general study of this underrated reaction was conducted and revealed that Azetidines can undergo smooth nucleophilic ring-opening reactions to highly functionalized γ-chloroamines in the presence of a variety of alkyl chloroformates under mild reaction conditions. Yields are usually good, and parameters governing this reaction were evaluated.
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Practical asymmetric preparation of Azetidine-2-carboxylic acid.
The Journal of organic chemistry, 2005Co-Authors: François Couty, Gwilherm Evano, Monica Vargas-sanchez, Gloria BouzasAbstract:Facile and straightforward syntheses of both enantiomers of Azetidine-2-carboxylic acid are described. The syntheses depart from inexpensive chemicals and allow for the production, in five to six steps, of practical quantities of each enantiomer. Synthetic highlights include the construction of the Azetidine ring using an intramolecular alkylation and the use of optically active α-methylbenzylamine as chiral auxiliary.
Paul A. Rupar - One of the best experts on this subject based on the ideXlab platform.
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Comparison of the Anionic Ring-Opening Polymerizations of N -(Alkylsulfonyl)Azetidines
Macromolecules, 2019Co-Authors: Elizabeth A. Rowe, Louis Reisman, Jennifer A. Jefcoat, Paul A. RuparAbstract:N-sulfonylAzetidines undergo anionic ring-opening polymerization (AROP) to form poly(N-sulfonylAzetidine)s, which are potential precursors to valuable polyimines. In this work, the impacts of alkyl sulfonyl substitution on the AROP of (N-(ethanesulfonyl)Azetidine (EsAzet), N-(2-propanesulfonyl)Azetidine (iPsAzet), and N-(tert-butylsulfonyl)Azetidine (tBsAzet) are studied and compared to those of the previously reported polymerization of N-(methanesulfonyl)Azetidine (MsAzet). The polymerization kinetics of EsAzet and iPsAzet is of the first order with respect to their monomers and produces p(EsAzet) and p(iPsAzet), which are both soluble in DMF and DMSO. In contrast, the polymerization of tBsAzet proceeds only to low conversion due to precipitation of p(tBsAzet) under identical conditions. At lower temperatures (120 °C), iPsAzet polymerizes with the fastest rate, while at higher temperatures (180 °C), the rate of MsAzet is the fastest. The reordering of the relative polymerization rates of MsAzet, EsAzet, ...
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Aziridines and Azetidines: Building blocks for polyamines by anionic and cationic ring-opening polymerization
Polymer Chemistry, 2019Co-Authors: Tassilo Gleede, Louis Reisman, Paul A. Rupar, Elisabeth Rieger, Pierre Canisius Mbarushimana, Frederik R. WurmAbstract:Despite the difficulties associated with controlling the polymerization of ring-strained nitrogen containing monomers, the resulting polymers have many important applications, such as antibacterial and antimicrobial coatings, CO2 adsorption, chelation and materials templating, and non-viral gene transfection. This review highlights the recent advances on the polymerizations of aziridine and Azetidine. It provides an overview of the different routes to produce polyamines, from aziridine and Azetidine, with various structures (i.e. branched vs. linear) and degrees of control. We summarize monomer preparation for cationic, anionic and other polymerization mechanisms. This comprehensive review on the polymerization of aziridine and Azetidine monomers will provide a basis for the development of future macromolecular architectures using these relatively exotic monomers.
Zhilai Hong - One of the best experts on this subject based on the ideXlab platform.
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Azetidine-Containing Alkaloids Produced by a Quorum-Sensing Regulated Nonribosomal Peptide Synthetase Pathway in Pseudomonas aeruginosa
Angewandte Chemie International Edition, 2019Co-Authors: Zhilai Hong, Arnaud Bolard, Caroline Giraud, Sébastien Prevost, Grégory Genta-jouve, Christiane Deregnaucourt, Susanne Häussler, Katy JeannotAbstract:Pseudomonas aeruginosa displays an impressive metabolic versatility, which ensures its survival in diverse environments. Reported herein is the identification of rare Azetidine-containing alkaloids from P. aeruginosa PAO1, termed azetidomonamides, which are derived from a conserved, quorum-sensing regulated nonribosomal peptide synthetase (NRPS) pathway. Biosynthesis of the Azetidine motif has been elucidated by gene inactivation, feeding experiments, and biochemical characterization in vitro, which involves a new S-adenosylmethionine-dependent enzyme to produce Azetidine 2-carboxylic acid as an unusual building block of NRPS. The mutants of P. aeruginosa unable to produce azetidomonamides had an advantage in growth at high cell density in vitro and displayed rapid virulence in Galleria mellonella model, inferring functional roles of azetidomonamides in the host adaptation. This work opens the avenue to study the biological functions of azetidomonamides and related compounds in pathogenic and environmental bacteria.
