Rafael Ballesteros-Garrido

[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.

From six-coordinate to eight-coordinate iron(II) complexes with pyridyltriazolo-pyridine frameworks

A new octacoordinated Fe(II) compound, [FeII(LN4)2](BPh4)2·3CH2Cl2, as an example of the scarce FeN8 systems, has been isolated with a tetradentate triazolopyridine-based ligand from a solution containing the related hexacoordinated [FeII(LN3)2]2+ complex, with LN3 = pyridyltriazolo-pyridyl-bromopyrimidine and LN4 = bis(pyridyltriazolo-pyridine).

Spectroscopic studies of the interaction of 3-(2-thienyl)-[1,2,3]triazolo[1,5-a]pyridine with 2,6-dimethyl-β-cyclodextrin and ctDNA

The inclusion complexation behavior of 3-(2-thienyl)-[1,2,3]triazolo[1,5-a] pyridine (TTP) with native β-cyclodextrin and derivatized cyclodextrins was investigated. Stability constants for complexes with 1 : 1 molar ratios were calculated from phase solubility diagrams. The solubilizing efficiency of the TTP inclusion complex is enhanced in the order of DMβCD > HPβCD > βCD. The TTP-DMβCD inclusion complex was further characterized in solution by means of absorption, fluorescence, 2D NMR and molecular modeling methods. The thermodynamic studies indicate that the inclusion of TTP into the cyclodextrin cavity is mainly an enthalpy-driven process. The 2D NMR studies revealed that the thienyl moiety of TTP is inserted into the CD cavity while the triazolopyridine protrudes the primary rim of the DMβCD, which are in good agreement with docking results. The fluorescence titration of TTP by ctDNA suggested that the quenching mechanism is a dynamic quenching procedure resulting from the temperature dependence of the TTP-ctDNA complex. Thermodynamics of the interaction revealed that the positive values of ΔH and ΔS announced that the binding process was primarily driven by hydrophobic forces indicating that TTP interacts with ctDNA by means of the minor groove. These results are in good agreement with docking experiments and iodide experiments which reinforce TTPs interactions in the minor groove.

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.

1,2,3-Triazoles Fused to Aromatic Rings

The structure, synthesis, reactivity and applications of 1,2,3-triazoles fused to aromatic rings are described. These compounds have been classified in two groups by a structural approach: (a) fused 1,2,3-triazoles without a bridgehead nitrogen atom and (b) fused 1,2,3-triazoles with a bridgehead nitrogen atom. Although both systems present a similar structure, the synthetic procedures and their reactivity are different.

Straight Access to Indoles from Anilines and Ethylene Glycol by Heterogeneous Acceptorless Dehydrogenative Condensation

The development of original strategies for the preparation of indole derivatives is a major goal in drug design. Herein, we report the first straight access to indoles from anilines and ethylene glycol by heterogeneous catalysis, based on an acceptorless dehydrogenative condensation, under noninert conditions. In order to achieve high selectivity, a combination of Pt/Al2O3 and ZnO have been found to slowly dehydrogenate ethylene glycol generating, after condensation with the amine and tautomeric equilibrium, the corresponding pyrrole-ring unsubstituted indoles.

Synthesis and in vitro leishmanicidal activity of novel [1,2,3]triazolo[1,5-a]pyridine salts

Leishmaniasis remains a significant worldwide problem; it is of great interest to develop new drugs to fight this disease. Recently we described some [1,2,3]triazolo[1,5-a]pyridine compounds with significant leishmanicidal activity. The importance of water solubility in drug action made us realise that we could transform non charged triazolopyridines into charged analogues that could increase the degree of water solubility. With this objective we report here the synthesis of novel [1,2,3]triazolo[1,5-a]pyridinium salts 2–7 from triazolopyridines 1, and the study of their in vitro leishmanicidal activity. The activity was tested on Leishmania infantum, Leishmania braziliensis and Leishmania donovani parasites, using promastigote and intracellular amastigote forms. The cytotoxicity of the tested compounds on J774.2 macrophage cells was also measured. Five of the tested compounds (2b, 4a, 4c, 6, 7d) showed selectivity indexes higher than those of the reference drug Glucantime for the three Leishmania species. Moreover, the data on infection rate and on amastigotes showed that these compounds are the most active against the three Leishmania species. The changes in the excretion product profiles of parasites treated with the compounds were also consistent with substantial cytoplasmic alterations. On the other hand, the most active compounds were potent inhibitors of Fe-SOD in the three parasite species considered whereas their impact on human CuZn-SOD was low.

Synthesis of new terpyridine-like ligands based on triazolopyridines and benzotriazoles

Herein, terpyridine triazole-based analogs bearing benzotriazoles or/and triazolopyridines are prepared via copper catalysis, where the arrangement of the nitrogen atoms is proven to be crucial to the spectroscopic properties of these ligands.

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 σ-donation of the nitrogen (N1) lone pair to phosphorus. This family of compounds behaves as strong fluorophores with high quantum yields.

Synthesis of new fluorescent amino acids with a triazolopyridine core: diacid sensors

A new family of amino acid containing pyridine–triazolopyridine cores has been prepared by means of a copper catalysed reaction. These compounds exhibit an intense emission that has been employed to sense the distance between two carboxylic acids in a linear molecule, from oxalic to glutaric acids.