Israel Carreira-Barral

Universidad de Burgos | UBU · Chemistry (Area: Organic Chemistry)

We report on an innovative method to measure the Zn(II) concentration in pet food commercial pet food samples, both wet and dry food. It is based on a colorimetric sensory polymer prepared from commercial monomers and 0.5% of a synthetic monomer having a quinoline sensory core (N-(8-(2-azidoacetamido)quinolin-5-yl)methacrylamide). We obtained the s...

G-quadruplex (G4) structures are non-canonical DNA/RNA secondary structures able to form within guanine rich nucleic acids sequences. They are present in several regions of the human genome including gene promoters, untranslated sequences, and telomeres. Due to their biological relevance G4 structures are considered important drug targets, in parti...

Roseophilin is an alkaloid structurally related to prodiginines . The intriguing pharmacological properties of these derivatives have prompted us to prepare synthetic compounds 1–3 inspired by their structure and to explore their transmembrane anion transport activity. The methoxyfuran heterocycle impacts the anionophoric activity of the compounds...

Overcoming resistance is one of the most challenging features in current anticancer therapy. Autophagy is a cellular process that confers resistance in some advanced tumors, since it enables cancer cells to adapt to stressful situations, such as anticancer treatments. Hence, the inhibition of this cytoprotective autophagy leads to tumor cells sensi...

The diastereoselective synthesis of two families of pyrrolopiperazine-2,6-diones is presented. These compounds were prepared by one-pot Ugi/nucleophilic substitution/N-acylation/debenzoylation/(elimination) sequences. This novel route provides straightforward access to a wide variety of pyrrolopiperazine-2,6-diones with high chemical yields and com...

A new family of squaramide-based anionophores (L1-L8) have been synthesised and fully characterised with the aim to investigate the effect of indolyl substituents on their anion binding and transmembrane transport properties. L1, L2, L6, and L8, bearing a 7-indolyl/indol-7-yl moiety as the substituent, were found to be the most efficient of the ser...

Selection of the appropriate base in Ugi/post-condensation sequences allows the selective syntheses of different ring-size functionalized lactams. The developed methodology uses inexpensive bases under mild and non-sensitive conditions leading to...

The liposomal membrane transport assay, which uses 8-hydroxypyrene-1,3,6-trisulfonic acid to monitor the internal pH of the vesicles (the HPTS assay), is a widely used technique for analysing the activity of anionophore-facilitated transport across a phospholipid membrane. This paper describes the stepwise technique to conduct this transport assay,...

The antitumor activity of imidazolium salts is highly dependent upon their lipophilicity that can be tuned by the introduction of different hydrophobic substituents on the nitrogen atoms of the imidazolium ring of the molecule. Taking this into consideration, we have synthesized and characterized a series of tripodal imidazolium salts derived from...

The vesicular anion transport activity assay, which uses 8-hydroxypyrene-1,3,6-trisulfonic acid to monitor the internal pH of the vesicles (the HPTS assay), is a widely used technique for analysing the activity of anionophore facilitated transport across a phospholipid membrane. This methods paper describes the stepwise technique to conduct this tr...

The vesicular anion transport activity assay, which uses 8-hydroxypyrene-1,3,6-trisulfonic acid to monitor the internal pH of the vesicles (the HPTS assay), is a widely used technique for analysing the activity of anionophore facilitated transport across a phospholipid membrane. This methods paper describes the stepwise technique to conduct this tr...

The vesicular anion transport activity assay, which uses 8-hydroxypyrene-1,3,6-trisulfonic acid to monitor the internal pH of the vesicles (the HPTS assay), is a widely used technique for analysing the activity of anionophore facilitated transport across a phospholipid membrane. This methods paper describes the stepwise technique to conduct this tr...

The vesicular anion transport activity assay, which uses 8-hydroxypyrene-1,3,6-trisulfonic acid to monitor the internal pH of the vesicles (the HPTS assay), is a widely used technique for analysing the activity of anionophore facilitated transport across a phospholipid membrane. This methods paper describes the stepwise technique to conduct this tr...

The use of arylglyoxal as starting material in Passerini and Ugi reactions affords β-ketoamides. This has allowed to study keto-enol tautomerism in these systems and assess the way in which the presence of acyloxy or aminoacyl groups bound to the C2 position affects such tautomerism, and to investigate the reactivity of both the enol and carbonyl f...

Prodiginines and tambjamines are anion-selective ionophores capable of facilitating the transport of anions across the plasma membrane in mammalian cells. One of the potential applications of these anionophores is the possibility of employing them as a substitutive therapy for pathologies involving anion channels, as in cystic fibrosis. We have stu...

We have developed a new sensory material for the rapid and inexpensive determination of Zn(II), and we have carried out a proof of concept for the determination of Zn(II) in biological samples. The interaction with Zn(II) generates an OFF-ON fluorescence process on the material, which can be recorded both with a fluorimeter and with a smartphone by...

Cystic fibrosis (CF) is a genetic disease characterized by the lack of cystic fibrosis transmembrane conductance regulator (CFTR) protein expressed in epithelial cells. The resulting defective chloride and bicarbonate secretion and imbalance of the transepithelial homeostasis lead to abnormal airway surface liquid (ASL) composition and properties....

A novel class of transmembrane anion carriers, the click- tambjamines, display remarkable anionophoric activities in model liposomes and living cells. The versatility of this building block for the generation of...

Eight N,N´-diarylisophthalamide/dipicolineamide derivatives have been synthesised and fully characterised, both in solution and in the solid state. The transmembrane anion transport properties of these compounds have been studied by chloride-selective electrode and fluorescence experiments. The substitution pattern of the aromatic moieties determin...

The synthesis of three novel families of pyrrolo[2,1-c][1,4]benzodiazepine-5-ones is described. The compounds were prepared according to a three-step sequence, involving an Ugi reaction, building of the pyrrolo nucleus and reduction-cyclisation to the corresponding diazepine. Depending on the amine employed in the synthesis of the Ugi adducts, diff...

Herein we present the synthesis of two ligands containing two di(2-picolyl)amine (DPA) units linked by either a 1,1'-(pyridine-2,6-diyl)bis(3-ethylurea) (L1) or a 1,1'-(1,3-phenylene)bis(3-ethylurea) (L2) spacer. The corresponding binuclear CuII and ZnII complexes were prepared and isolated. The X-ray structures of the L1 ligand and the [Cu2L1Cl2]2...

Highly active transmembrane anion transporters have demonstrated their activity against antibiotic-resistant and clinically relevant bacterial strains. This type of compounds offers promise as strategy to develop novel antibacterial agents

Background and purpose: Cystic fibrosis (CF) is a lethal autosomal recessive genetic disease that originates from the defective function of the CFTR protein, a cAMP-dependent anion channel involved in fluid transport across epithelium. Due to their capability to replace the ion transport independently from the genetic mutation that affects the CFT...

We report a series of Cu(II) and Zn(II) complexes with different ligands containing a dipicolyl unit functionalized with urea groups that may contain or not a phenylboronic acid function. These complexes were designed for the recognition of phosphorylated anions through coordination to the metal ion reinforced by hydrogen bonds involving the anion...

Pyrrolo[2,1-c][1,4]benzodiazepines (PBDs) and other benzo-fused N-heterocycles constitute privileged structures found in numerous bioactive compounds. Thus, developing simple and selective syntheses to furnish these derivatives from easily accessible starting materials is an important and challenging goal. In this work, novel pyrrolobenzodiazepine...

The ditopic receptor L3 [1-(2-((7-(4-(tert-butyl)benzyl)-1,4,7,10-tetraazacyclododecan-1-yl)methyl)phenyl)-3-(3-nitrophenyl)urea] containing a macrocyclic cyclen unit for Cu(ii)-coordination and a urea moiety for anion binding was designed for recognition of metal salts. The X-ray structure of [CuL3(SO4)] shows that the sulfate anion is involved in...

The synthesis and structural characterization of six sodium complexes with bibracchial lariat ethers containing aniline or benzimidazole side arms, and derived from 1,7-diaza-12-crown-4, 1,10-diaza-15-crown-5 or 4,13-diaza-18-crown-6, are reported. The X-ray structures of four of these compounds have been obtained. Additionally, the X-ray structure...

The ability of Cu(II) and Zn(II) complexes of the ditopic receptor H2L [1-(2-((bis(pyridin-2-ylmethyl)amino)methyl)phenyl)-3-(3-nitrophenyl)urea] for anion recognition is reported. In the presence of weakly coordinating anions such as ClO4(-), the urea group binds to the metal ion (Cu(II) or Zn(II)) through one of its nitrogen atoms. The study of t...

Herein we report the synthesis and structural characterization of Mg(II), Ca(II), Sr(II) and Ba(II) complexes with bibracchial lariat ethers derived from 1,7-diaza-15-crown-5 and 1,7-diaza-12-crown-4 containing aniline or benzimidazole pendant arms. The solid state structures of most of them have been determined by using single crystal X-ray crysta...

Herein, we report the synthesis and structural characterization of alkaline-earth complexes with the bibracchial lariat ethers N,N′-bis(2-aminobenzyl)-4,13-diaza-18-crown-6 (L2) and N,N′-bis(benzimidazol-2ylmethyl)-4,13-diaza-18-crown-6 (L4). The X-ray crystal structures of the Ca(II) and Sr(II) complexes of L2 show the pendant arms of the ligand d...