0000000000877738
AUTHOR
Frédéric R. Leroux
Efficient palladium catalyzed synthesis of heteroaromatic sulfoxides
Abstract The present Letter describes the efficient synthesis of novel heteroaromatic sulfoxides by means of a palladium catalyzed heteroarylation of sulfenate anions. Triazolopyridine, pyridine and thiophene sulfoxides can be obtained under mild conditions and in high yield from the corresponding heteroaryl bromides.
Triazolopyridines. Part 28. The ring–chain isomerization strategy: triazolopyridine- and triazoloquinoline–pyridine based fluorescence ligands
Abstract The ring–chain isomerization of [1,2,3]triazolo[1,5-a]pyridines or [1,2,3]triazolo[1,5-a] quinolines has been efficiently employed as a tool to provide tridentate fluorescent structures. Based on these scaffolds, a new family of highly fluorescent compounds has been synthesized and evaluated for the recognition of zinc or copper cations. In addition, the 1:1 Zn+2-L complex of a naphthalene triazolopyridine–pyridine derivative revealed high efficiency as sensor for anions providing large binding constants for nitrite and cyanide.
Unusual phosphine oxidation: new triazolopyridyl-quinolyl phosphine oxide fluorescent dyes
3-(2-Pyridyl)-[1,2,3]triazolo[1,5-a]quinolylphosphines suffer an unusual phosphine oxidation due to their special geometry that allows a s-donation of the nitrogen (N1) lone pair to phosphorus. This family of compounds behaves as strong fluorophores with high quantum yields.
ChemInform Abstract: Efficient Synthesis of Quaternary and P-Stereogenic Phosphonium Triflates.
An efficient and general method for the preparation of achiral and chiral phosphonium salts is reported. This synthesis is based on the quaternization of phosphines and their derivatives with arynes generated in situ from 2-(trimethylsilyl)aryl triflates. This methodology is successfully applied to the synthesis of new valuable P-stereogenic phosphonium triflates.
Stereoselective Synthesis of P-Chirogenic Dibenzophosphole-Boranes via Aryne Intermediates
A new aryne-mediated tandem cross-coupling/P-cyclization sequence starting from tertiary phosphine-boranes and 1,2-dibromobenzenes is reported. P-chirogenic dibenzophospholes become accessible in a regio-, chemo-, and diastereoselective way.
Triazolopyridines. Part 26: The preparation of novel [1,2,3]triazolo[1,5-a]pyridine sulfoxides
Abstract The regioselective synthesis of new triazolopyridine halides and sulfoxides with the substituent in all different ring positions of [1,2,3]triazolo[1,5- a ]pyridines is presented. The triazolo ring opening reaction of some representative sulfoxides to obtain disubstituted pyridines is also studied.
ChemInform Abstract: Triazolopyridines. Part 26. The Preparation of Novel [1,2,3]Triazolo[1,5-a]pyridine Sulfoxides.
Abstract The regioselective synthesis of new triazolopyridine halides and sulfoxides with the substituent in all different ring positions of [1,2,3]triazolo[1,5- a ]pyridines is presented. The triazolo ring opening reaction of some representative sulfoxides to obtain disubstituted pyridines is also studied.
3-(Pyridin-2-yl)[1,2,3]triazolo[1,5-a]quinoline: A Theoretical and Experimental Analysis of Ring-Chain Isomerisation
In the course of the synthesis of new fluorophores for molecular recognition an experimental (1H NMR) and theoretical (DFT) study of the ring-chain isomerism of 3-(pyridin-2-yl)[1,2,3]triazolo[1,5-a]quinoline derivatives (A) into 2-([1,2,3]triazolo[1,5-a]pyridin-3-yl)quinoline derivatives (B) has been carried out. The rearrangement is influenced by steric and electronic effects of the substituents present on the quinoline ring. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Triazolopyridines. Part 25: Synthesis of new chiral ligands from [1,2,3]triazolo[1,5-a]pyridines
The synthesis of new chiral triazolopyridine ligands possessing fluorescent properties is described. The triazolo ring opening was studied in order to obtain new chiral 2,6-disubstituted pyridines. A preliminary coordination assay with Zn(II) is also presented.
Stereoselective synthesis of o-bromo (or iodo)aryl P-chirogenic phosphines based on aryne chemistry.
The efficient synthesis of chiral or achiral tertiary phosphines bearing an o-bromo (or iodo)aryl substituent is described. The key step of this synthesis is based on the reaction of a secondary phosphine borane with the 1,2-dibromo (or diiodo)arene, owing to the formation in situ of an aryne species in the presence of n-butyllithium. When P-chirogenic secondary phosphine boranes were used, the corresponding o-halogeno-arylphosphine boranes were obtained without racemization in moderate to good yields and with ee up to 99%. The stereochemistry of the reaction, with complete retention of the configuration at the P atom, has been established by X-ray structures of P-chirogenic o-halogenopheny…
The [1,2,3]triazolo[1,5-a]pyridine ring: a sensitive sensor for the electronic profile of phosphorus substituents.
The unique nature of the [1,2,3]triazolo[1,5-a]pyridine reveals without any external perturbation the electronic contribution of various substituents to the phosphorus atom in phosphines, based on the equilibrium of two possible ring-chain isomers.
Efficient synthesis of quaternary and P-stereogenic phosphonium triflates
An efficient and general method for the preparation of achiral and chiral phosphonium salts is reported. This synthesis is based on the quaternization of phosphines and their derivatives with arynes generated in situ from 2-(trimethylsilyl)aryl triflates. This methodology is successfully applied to the synthesis of new valuable P-stereogenic phosphonium triflates.
[1,2,3]Triazolo[1,5-a]pyridyl phosphines reflecting the influence of phosphorus lone pair orientation on spectroscopic properties
A series of new triazolopyridine-based phosphines has been prepared. These compounds revealed unexpected spectroscopic patterns. In particular, the NMR spectra are highly dependent on the relative conformational preference of the phosphine substituent at C7. Here, we report on their complete NMR analysis, X-ray structures and DFT calculations that confirm the particular arrangement of the phosphorus lone pair orbital related to the substituent pattern of the chosen phosphine.
The deprotonative metalation of [1,2,3]triazolo[1,5-a]quinoline. Synthesis of 8-haloquinolin-2-carboxaldehydes
New highly functionalized triazoloquinolines were synthesized by applying polar organometallic methods. Double metalation and functionalization provided 3,9-dihalogenated triazoloquinolines. Ring opening of the triazole with loss of nitrogen has been performed for the first time with 3,9-dihalogenated triazoloquinolines allowing the access toward 8-haloquinolin-2-carboxaldehydes under oxidant-free conditions. This approach demonstrates that the triazole ring can be used as protecting group of 2-quinolinecarboxaldehydes, activating the C9-position for lithiation and functionalization by triazole ring opening. 8-Haloquinoline-2-carbaldehydes become in this way readily available.
[1,2,3]Triazolo[1,5-a]pyridine derivatives as molecular chemosensors for zinc(ii), nitrite and cyanide anions
Three recently prepared tridentate ligands TPF, TPS and TPT, based on the triazolopyridine–pyridine nucleus possessing fluorescent properties, have been tested as chemosensors for metal ions. A particular response is obtained in the case of ZnTPT+2. The Zn2+ TPT 1 : 1 complex has proved to be an efficient chemosensor for anions especially nitrite and cyanide.
A theoretical and experimental study of the racemization process of hexaaza[5]helicenes
A dynamic 1H NMR study, together with DFT calculations, of bis-([1,2,3]triazolo)[1,5-a:5′,1′-k][1,10]phenanthroline 2 has allowed to identify the ring and open forms of a new example of ring/chain tautomerism, as well as their interconversion barriers (ring/ring and ring/open). The barrier of the exchange process between the chain forms and the ring form was found higher than the 'racemization' process in the closed form, so the ring opening does not contribute to the 'racemization'. The di-1,10-methyl and di-1,10-iodo derivatives have been prepared and their properties calculated.
Synthesis and structural properties of hexaaza[5]helicene containing two [1,2,3]triazolo[1,5-a]pyridine moieties
Abstract We have synthesized a novel hexaaza[5]helicene in a straightforward way from neocuproine. The crystal structure has been elucidated with direct-space strategy TALP which demonstrates the power of the powder X-ray diffraction technique. In this crystal structure it is possible to see an interplanar angle of 33(1)° between the two triazolopyridine rings. The centrosymmetric crystal structure is a racemic mixture, but the resolution was not possible due to a ring-chain isomerization in a solution that produces a dynamic racemization.
CCDC 868765: Experimental Crystal Structure Determination
Related Article: Vincent Diemer, Anaïs Berthelot, Jérôme Bayardon, Sylvain Jugé, Frédéric R. Leroux, and Françoise Colobert|2012|J.Org.Chem.|77|6117|doi:10.1021/jo3009098
CCDC 868764: Experimental Crystal Structure Determination
Related Article: Vincent Diemer, Anaïs Berthelot, Jérôme Bayardon, Sylvain Jugé, Frédéric R. Leroux, and Françoise Colobert|2012|J.Org.Chem.|77|6117|doi:10.1021/jo3009098
CCDC 868766: Experimental Crystal Structure Determination
Related Article: Vincent Diemer, Anaïs Berthelot, Jérôme Bayardon, Sylvain Jugé, Frédéric R. Leroux, and Françoise Colobert|2012|J.Org.Chem.|77|6117|doi:10.1021/jo3009098
CCDC 868763: Experimental Crystal Structure Determination
Related Article: Vincent Diemer, Anaïs Berthelot, Jérôme Bayardon, Sylvain Jugé, Frédéric R. Leroux, and Françoise Colobert|2012|J.Org.Chem.|77|6117|doi:10.1021/jo3009098
CCDC 868767: Experimental Crystal Structure Determination
Related Article: Vincent Diemer, Anaïs Berthelot, Jérôme Bayardon, Sylvain Jugé, Frédéric R. Leroux, and Françoise Colobert|2012|J.Org.Chem.|77|6117|doi:10.1021/jo3009098
CCDC 868769: Experimental Crystal Structure Determination
Related Article: Vincent Diemer, Anaïs Berthelot, Jérôme Bayardon, Sylvain Jugé, Frédéric R. Leroux, and Françoise Colobert|2012|J.Org.Chem.|77|6117|doi:10.1021/jo3009098
CCDC 868768: Experimental Crystal Structure Determination
Related Article: Vincent Diemer, Anaïs Berthelot, Jérôme Bayardon, Sylvain Jugé, Frédéric R. Leroux, and Françoise Colobert|2012|J.Org.Chem.|77|6117|doi:10.1021/jo3009098