Synthesis of Well-Defined Head-to-Tail-Type Oligothiophenes by Regioselective Deprotonation of 3-Substituted Thiophenes and Nickel-Catalyzed Cross-Coupling Reaction

Iterative growth of thiophene oligomers by single-step extensions has been realized by regioselective metalation of 3-substituted thiophenes with the Knochel–Hauser base (TMPMgCl·LiCl) and coupling with bromothiophene using a nickel catalyst. Treatment of 3-hexylthiophene with TMPMgCl·LiCl induces metalation at the 5-position selectively. Subsequent addition of 2-bromo-3-hexylthiophene and a nickel catalyst leads to the corresponding bithiophene. The obtained bithiophene is converted to the terthiophene and then to the quaterthiophene by repeating the similar protocol. A concise synthesis of MK-1 and MK-2, which are organic dye molecules bearing an oligothiophene moiety that are used in photovoltaic cells, has been achieved

Synthesis of Oligo(thienylene-vinylene) by Regiocontrolled Deprotonative Cross-Coupling

Concise synthesis of oligo­(thienylene-vinylene) with a head-to-tail type structure is achieved by regioselective deprotonative coupling of 3-hexylthiophene. The palladium catalyzed reaction of 3-hexylthiophene with (<i>E</i>)-2-(2-bromoethenyl)-3-hexyl­thiophene takes place to afford head-to-tail type <i>trans</i>-1,2-dithienyl­ethene. Further extension of a vinylthiophene unit is similarly performed in an iterative manner

2-aminoethoxydiphenyl borate provides an anti-oxidative effect and mediates cardioprotection during ischemia reperfusion in mice

<div><p>Excessive levels of reactive oxygen species (ROS) and impaired Ca²⁺ homeostasis play central roles in the development of multiple cardiac pathologies, including cell death during ischemia-reperfusion (I/R) injury. In several organs, treatment with 2-aminoethoxydiphenyl borate (2-APB) was shown to have protective effects, generally believed to be due to Ca²⁺ channel inhibition. However, the mechanism of 2-APB-induced cardioprotection has not been fully investigated. Herein we investigated the protective effects of 2-APB treatment against cardiac pathogenesis and deciphered the underlying mechanisms. In neonatal rat cardiomyocytes, treatment with 2-APB was shown to prevent hydrogen peroxide (H₂O₂) -induced cell death by inhibiting the increase in intracellular Ca²⁺ levels. However, no 2-APB-sensitive channel blocker inhibited H₂O₂-induced cell death and a direct reaction between 2-APB and H₂O₂ was detected by ¹H-NMR, suggesting that 2-APB chemically scavenges extracellular ROS and provides cytoprotection. In a mouse I/R model, treatment with 2-APB led to a considerable reduction in the infarct size after I/R, which was accompanied by the reduction in ROS levels and neutrophil infiltration, indicating that the anti-oxidative properties of 2-APB plays an important role in the prevention of I/R injury <i>in vivo</i> as well. Taken together, present results indicate that 2-APB treatment induces cardioprotection and prevents ROS-induced cardiomyocyte death, at least partially, by the direct scavenging of extracellular ROS. Therefore, administration of 2-APB may represent a promising therapeutic strategy for the treatment of ROS-related cardiac pathology including I/R injury.</p></div

Treatment with 2-APB attenuates reactive oxygen species (ROS) production and inflammatory responses after cardiac ischemia/reperfusion (I/R) in mice.

<p>(A) Representative fluorescence images of dihydroethidium (DHE)-stained heart sections obtained at 24 h of reperfusion from the 2-APB- or vehicle-treated mice. Scale bar: 50 μm. (B) Fluorescence intensity obtained from eight images, expressed as the mean fluorescence intensity normalized to the levels obtained from mice of the vehicle sham group. Results are presented as mean values ± SEM obtained from 4–5 mice. *<i>P</i><0.05 vs. I/R 2-APB-treated sample. (C and D) Effect of 2-APB on diacron reactive oxygen metabolites (d-ROMs) (C) and biological antioxidant potential (BAP)/d-ROMs (D) in mice that underwent 30 min of ischemia followed by 30 min or 6 h of reperfusion. Results are presented as mean values ± SEM obtained from 4–6 mice. 105±4 <i>vs</i>. 91±4 in U.CARR (6 h reperfusion in d-ROMs) and 26.2±1.3 <i>vs</i>. 31.8±1.5 in μM/U.CARR (6 h reperfusion in BAP/d-ROMs). *<i>P</i><0.05 <i>vs</i>. I/R vehicle-treated 6 hours reperfusion group, obtained using Student’s <i>t</i>-test. (E) <i>Il6</i>, <i>Il1β</i>, and <i>Tnf-α</i> expression levels in mouse hearts. Results are presented as mean values ± SEM obtained from 7–8 mice. *<i>P</i><0.05 <i>vs</i>. I/R vehicle-treated 6 h reperfusion group, obtained using Student’s <i>t</i>-test. (F) Representative images of heart sections obtained from different animal groups, stained with anti-Ly-6G antibody (Gr-1) for the detection of neutrophils. Scale bar: 50 μm. (G) Quantification of Gr-1-positive cells in ischemic myocardium presented as the number of positive cells/mm². Results are presented as mean values ± SEM obtained from 6–7 mice; 454±52 cells/mm² <i>vs</i>. 140±22 cells/mm² for Ly-6G-positive granulocytes. **<i>P</i><0.01 <i>vs</i>. I/R vehicle-treated group, obtained using Student’s <i>t</i>-test.</p

Hydrogen peroxide directly reacts with 2-APB.

<p>(A) Neonatal rat cardiomyocytes (NRCMs) were loaded with 5 μM DCF, and treated with 2-APB and H₂O₂. Average results of %Fluorescence increase were obtained from three independent experiments. (B) Intracellular ROS levels at 60 min after H₂O₂ stimulation were estimated from DCF fluorescence levels in NRCMs pretreated or not with 2-APB. Results of %Fluorescence increase are presented as mean values ± SEM obtained in three independent experiments. *<i>P</i><0.05 <i>vs</i>. untreated control, ^†<i>P</i><0.05 <i>vs</i>. H₂O₂ treated samples, obtained using one-way ANOVA. (C) NRCMs were loaded with 5 μM DCF and treated with 2-APB for 1 h, followed by stimulation with 2 mM PE. Average results of %Fluorescence increase were obtained from three independent experiments. (D) Intracellular ROS levels at 60 min after PE stimulation, estimated using DCF fluorescence intensity levels in NRCMs pretreated or not with 2-APB. Results of %Fluorescence increase are presented as mean values ± SEM obtained in three independent experiments. **<i>P</i><0.01 <i>vs</i>. untreated control, using one-way ANOVA. (E) Representative ¹H-NMR spectra obtained from 2-APB (spectrum A) or 2-APB in direct reaction with H₂O₂ for 5 min (spectrum B) or 60 min (spectrum C) are shown. (F) Representative thin-layer chromatography (TLC) images are presented. Reaction product indicates samples obtained from the reaction between 2-APB with H₂O₂ used for NMR measurement. Comparison between the reaction products and authentic H₂O₂ (left), 2-APB (middle), or phenol (right) is presented.</p

Treatment with 2-APB attenuated H₂O₂-induced cell death and Ca²⁺ influx in cardiomyocytes.

<p>(A) Analysis of the viability of neonatal rat cardiomyocytes (NRCMs) with or without 100 μM 2-APB pretreatment for 1 h, followed by subsequent stimulation with 100 μM H₂O₂ for 4 h. Results are presented as mean ± SEM obtained in five to seven independent experiments. (B) Representative fura-2 ratios from NRCMs pretreated with or without 2-APB for 1 h, followed by stimulation with H₂O₂. (C) NRCMs were pretreated or not with 5 μM BAPTA-AM, which was followed by H₂O₂ treatment and the degree of cell survival is presented as mean values ± SEM obtained in six or seven independent experiments. (D) Representative fura-2 ratios from NRCMs pretreated or not with 10 μM BAPTA-AM for 1 h, followed by H₂O₂ treatment. (E) Representative fura-2 ratios obtained using NRCMs treated with 100 μM H₂O₂ in HBSS buffer with or without Ca²⁺ prepared by the administration of EDTA. **<i>P</i><0.01, compared with H₂O₂-treated samples, using one-way ANOVA.</p

Specific inhibition of 2-APB-sensitive Ca²⁺ channels failed to prevent H₂O₂-induced cardiomyocyte death.

<p>(A) Neonatal rat cardiomyocytes (NRCMs) were pretreated or not with xestospongin C, a specific IP₃R inhibitor, for 1 hour, which was followed by H₂O₂ treatment. Cell viability levels were determined. Results are shown as mean values ± SEM from three independent experiments. (B) Representative fura-2 ratio obtained using NRCMs pretreated or not with xestospongin C, followed by H₂O₂ treatment. (C) The expression levels of 2-APB-sensitive TRP channels in NRCMs were analyzed by RT-PCR. A representative image with a 40-cycle amplification is shown. (D-F) NRCMs were pretreated or not with SKF-96365 (D, a TRPC inhibitor), AA-861 (E, a TRPM7 inhibitor) and mefenamic acid (F, a TRPM3 inhibitor), followed by H₂O₂ treatment. Cell viability rate is presented. Results are presented as mean values ± SEM obtained in four independent experiments.</p

Additional file 1: Table S1. of Genetic and epigenetic stability of oligodendrogliomas at recurrence

Clinical characteristics of the patient cohort. Table S2. Sequence data summary. Table S3. List of the somatic mutations in this study. (XLSX 163 kb

Genotype counts and case-control association test results for SNPs rs4359426, rs170360 and rs223823.

<p><i>P</i> values of the two populations were calculated by logistic regression analysis under an additive model.</p><p>The combined <i>P</i> values were calculated using the inverse variance method. OR, odds ratio; CI, confidence interval.</p

Genotype counts and case-control association test results of seven tag SNPs.

<p><i>P</i> values of the two populations were calculated by logistic regression analysis under an additive model. The combined <i>P</i> values were calculated using the inverse variance method. OR, odds ratio; CI, confidence interval; -, not significant.</p