Selective recognition of neurotransmitters in aqueous solution by hydroxyphenyl aza-scorpiand ligands.

The synthesis, acid-base behaviour and anion recognition of neurotransmitters (dopamine, tyramine and serotonin) in aqueous solution of different aza-scorpiand ligands functionalized with hydroxyphenyl and phenyl moieties (L1-L3 and L4, respectively) have been studied by potentiometry, NMR, UV-Vis and fluorescence spectroscopy and isothermal titration calorimetry (ITC). The analysis of the potentiometric results shows the selective recognition of serotonin at physiological pH ( = 8.64 × 10) by L1.

Metal-organic frameworks in pursuit of size: the development of macroscopic single crystals.

Metal-organic frameworks are versatile structures with many different applications, from industry to the clinic. Despite multiple synthesis approaches being able to coordinate metals and organic ligands, some common strategies can be employed when the size of the final product is a target. Here, we review the most relevant examples of synthesized crystals of very large size (, macroscopic, in the scale of mm), emphasizing the critical parameters that impact the final crystal size and quality.

About the relevance of anion-π interactions in water.

Anion-π interactions are emerging as exotic features with potential applications in chemistry. In the last years, their relevance in living systems has been outlined, and so far there is no concluding significant evidence recognized about the participation of anion-π interactions in water because anion-π sensors contain large aromatic hydrophobic surfaces with limited solubility. By transforming a neutral heterocycle (for example quinoline) into its corresponding salt (quinolinium), we have been able to overcome these solubility issues, and new cationic water-soluble fluorophores have been prepared.

Acceptorless dehydrogenative condensation: synthesis of indoles and quinolines from diols and anilines.

The use of diols and anilines as reagents for the preparation of indoles represents a challenge in organic synthesis. By means of acceptorless dehydrogenative condensation, heterocycles, such as indoles, can be obtained. Herein we present an experimental and theoretical study for this purpose employing heterogeneous catalysts Pt/Al2O3 and ZnO in combination with an acid catalyst (p-TSA) and NMP as solvent.

Repositioning of leishmanicidal [1,2,3]Triazolo[1,5-a]pyridinium salts for Chagas disease treatment: Trypanosoma cruzi cell death involving mitochondrial membrane depolarisation and Fe-SOD inhibition.

Trypanosomatidae is a family of unicellular parasites belonging to the phylum Euglenozoa, which are causative agents in high impact human diseases such as Leishmaniasis, Chagas disease and African sleeping sickness. The impact on human health and local economies, together with a lack of satisfactory chemotherapeutic treatments and effective vaccines, justifies stringent research efforts to search for new disease therapies. Here, we present in vitro trypanocidal activity data and mode of action data, repositioning leishmanicidal [1,2,3]Triazolo[1,5-a]pyridinium salts against Trypanosoma cruzi, the aetiological agent of Chagas disease.

Probing the operability regime of an engineered ribocomputing unit in terms of dynamic range maintenance with extracellular changes and time.

Synthetic biology aims at engineering gene regulatory circuits to end with cells (re)programmed on purpose to implement novel functions or discover natural behaviors. However, one overlooked question is whether the resulting circuits perform as intended in variety of environments or with time. Here, we considered a recently engineered genetic system that allows programming the cell to work as a minimal computer (arithmetic logic unit) in order to analyze its operability regime.

Novel [1,2,3]triazolo[1,5-a]pyridine derivatives are trypanocidal by sterol biosynthesis pathway alteration.

To study a new series of [1,2,3]triazolo[1,5-α]pyridine derivatives as trypanocidal agents because current antichagasic pharmacologic therapy is only partially effective. The effect of the series upon epimastigotes and murine macrophages viability, cell cycle, cell death and on the metabolites of the sterol biosynthesis pathway was measured; also, docking in 14α-demethylase was analyzed. Compound inhibits 14α-demethylase producing an imbalance in the cholesterol/ergosterol synthesis pathway, as suggested by a metabolic control and theoretical docking analysis.

Bacterial Population Control with Macroscopic HKUST Crystals.

Macroscopic HKUST crystals were shown to release significant amounts of copper in saline medium at a slow rate, which was exploited to control the growth of a bacterial population. This was achieved in both liquid and solid media, the latter illustrating the local effect of the crystals. In addition, these nanostructured crystals of observable size were loaded with chloramphenicol to exert a joint metal-antibiotic action, going beyond the traditional oligodynamic effect.

Empirical modeling of material composition and size in MOFs prepared with ligand mixtures.

Systematic analyses of the composition and size of metal-organic frameworks built with Zn4O and terephthalic/amino-terephthalic acid mixtures, together with a kinetic assay, reveal how these ligands behave differently, which reveals the complexity of crystal growth in these frameworks and the ability to tune it on purpose.

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/AlO 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, Optical Properties, and DNA Interaction of New Diquats Based on Triazolopyridines and Triazoloquinolines.

New diquat derivatives based on [1,2,3]triazolo[1,5-a]pyridine and [1,2,3]triazolo[1,5-a]quinoline have been synthesized in excellent yields. To evaluate the effect of the alkyl bridge length, ethane and propane dibromo alkane substrates were used for their synthesis. Theoretical calculations predicted a very small energetic barrier between the two possible enantiomers P (R ) and M (S ), which makes them very difficult to resolve.

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.

Tunability by alkali metal cations of photoinduced charge separation in azacrown functionalized graphene.

A modified graphene oxide containing aza-9-crown-3 ether units covalently anchored has been prepared; aqueous suspensions of this material in the presence of Li(+), Na(+) and K(+) cations exhibit enhanced electrochemical response, enhanced photoinduced charge separation and longer lifetimes, facts that can be attributed to stabilization of electrons on graphene oxide by the nearby alkali metal cation-azacrown complexes.

Medium-sized rings versus macrocycles through rhodium-catalyzed ring-expansion reactions of cyclic acetals.

α-Diazo β-ketoesters and diketones react with cyclic acetals under Rh(II) catalysis to yield unprecedented polyoxygenated 8- and 9-membered rings in one pot. The reactions occur under mild conditions with yields up to 90%. A perfect regioselectivity is obtained, which can be rationalized through a mechanistic hypothesis that considers 1) the formation of an oxonium ylide, 2) its transformation into an unsaturated acyclic oxocarbenium electrophilic intermediate, and 3) an intramolecular nucleophilic attack in a direct application of Baldwin's rules.

[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.

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.