247 research outputs found
Nitrogen–Iodine Exchange of Diaryliodonium Salts: Access to Acridine and Carbazole
A nitrogen–iodine exchange
protocol of diaryliodonium salts
with sodium azide salt is developed for general construction of significant
functional acridines and carbazoles, in which introduction of nitrogen
at a late stage was successfully established avoiding heteroatom incompatibility.
Inorganic sodium azide served as the sole nitrogen atom source in
this transformation. The diversiform functional acridines and carbazoles
were comprehensively achieved through annulated diaryliodonium salts,
respectively. Notably, Acridine orange (a fluorescent indicator for
cell lysosomal dye) and Carprofen (a nonsteroidal anti-inflammatory
drug) were efficiently established through this protocol
Transition-Metal-Free Diarylannulated Sulfide and Selenide Construction via Radical/Anion-Mediated Sulfur–Iodine and Selenium–Iodine Exchange
A facile, straightforward
protocol was established for diarylannulated
sulfide and selenide construction through S–I and Se–I
exchange without transition metal assistance. Elemental sulfur and
selenium served as the chalcogen source. Diarylannulated sulfides
were systematically achieved from a five- to eight-membered ring.
A trisulfur radical anion was demonstrated as the initiator for this
radical process via electron paramagnetic resonance (EPR) study. OFET
molecules [1]ÂbenzoÂthienoÂ[3,2-<i>b</i>]Â[1]ÂbenzoÂthioÂphene
(BTBT) and [1]ÂbenzoÂthienoÂ[3,2-<i>b</i>]Â[1]ÂbenzoÂselenoÂphene
(BTBS) were efficiently established
Construction of Functionalized Annulated Sulfone via SO<sub>2</sub>/I Exchange of Cyclic Diaryliodonium Salts
A straightforward
protocol for diarylannulated sulfone construction
is efficiently established via SO<sub>2</sub>/I exchange of iodoniumÂ(III)
salts. Readily available inorganic Na<sub>2</sub>S<sub>2</sub>O<sub>5</sub> was served as a safe and convenient SO<sub>2</sub> surrogate.
Diverse functionalized diarylannulated sulfones were smoothly achieved
in good to excellent yields with great functional group compatibility.
Organic light emitting diodes (OLEDs) material molecules were subsequently
established via this method in gram scale. The unsymmetrical conjugated
systems with donor-acceptor groups and π-conjugation bridges
motifs, which substantially communicate electron mobility in semiconductor
material molecules, were successfully afforded under the facile conditions
of the exchange strategy
Controllable Sulfoxidation and Sulfenylation with Organic Thiosulfate Salts via Dual Electron- and Energy-Transfer Photocatalysis
Sulfoxides
and sulfides are two important functional groups in
organic molecules, containing different valence states of sulfur.
Both sulfoxidation and sulfenylation with common sulfurating reagents
were successfully tuned via a facile variation of the atmosphere under
photocatalyzed conditions. The sulfoxidation and sulfenylation transformations
involved tandem electron-/energy-transfer and single-electron-transfer
processes, respectively. Late-stage sulfoxidation for pharmaceuticals
and sugar derivatives was established to be highly compatible. Divergent
formal syntheses of sulfoxide/sulfide-containing marketed pharmaceuticals
were switchably implemented. Gram-scale operations further demonstrated
the practicability of the protocol
Geochronology and geochemistry of the Dabure basalts, central Qiangtang, Tibet: evidence for ~550Â Ma rifting of Gondwana
<div><p>Newly discovered basalts in the Dabure area (central Qiangtang block, northern Tibet) were subjected to laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U–Pb zircon dating, geochemical analyses, and zircon Hf isotope analyses. Dating of magmatic zircons from three basalt samples indicates that the Dabure basalts formed during the late Ediacaran (~550 Ma). Xenocrystic zircons yield ages of 700–1150 Ma, providing evidence of the Cryogenian crust in the Tibet block. The Dabure basalts are alkaline, rich in Ti and Fe, and are strongly enriched in light rare earth elements without Eu anomalies. The basalts are geochemically similar to within-plate basalts but are relatively depleted in Nb and Ta. Although the analysed zircons show differences in their Hf isotope compositions, the geochemical data suggest that the Dabure basalts were derived from enriched mantle and that the source magmas were contaminated by the continental crust. The basalts may have erupted during rifting at ~550 Ma (from the dating of magmatic zircons), and may have been a product of the initial breakup of Gondwanaland.</p></div
Construction of Functionalized Annulated Sulfone via SO<sub>2</sub>/I Exchange of Cyclic Diaryliodonium Salts
A straightforward
protocol for diarylannulated sulfone construction
is efficiently established via SO<sub>2</sub>/I exchange of iodoniumÂ(III)
salts. Readily available inorganic Na<sub>2</sub>S<sub>2</sub>O<sub>5</sub> was served as a safe and convenient SO<sub>2</sub> surrogate.
Diverse functionalized diarylannulated sulfones were smoothly achieved
in good to excellent yields with great functional group compatibility.
Organic light emitting diodes (OLEDs) material molecules were subsequently
established via this method in gram scale. The unsymmetrical conjugated
systems with donor-acceptor groups and π-conjugation bridges
motifs, which substantially communicate electron mobility in semiconductor
material molecules, were successfully afforded under the facile conditions
of the exchange strategy
Construction of Functionalized Annulated Sulfone via SO<sub>2</sub>/I Exchange of Cyclic Diaryliodonium Salts
A straightforward
protocol for diarylannulated sulfone construction
is efficiently established via SO<sub>2</sub>/I exchange of iodoniumÂ(III)
salts. Readily available inorganic Na<sub>2</sub>S<sub>2</sub>O<sub>5</sub> was served as a safe and convenient SO<sub>2</sub> surrogate.
Diverse functionalized diarylannulated sulfones were smoothly achieved
in good to excellent yields with great functional group compatibility.
Organic light emitting diodes (OLEDs) material molecules were subsequently
established via this method in gram scale. The unsymmetrical conjugated
systems with donor-acceptor groups and π-conjugation bridges
motifs, which substantially communicate electron mobility in semiconductor
material molecules, were successfully afforded under the facile conditions
of the exchange strategy
Construction of Functionalized Annulated Sulfone via SO<sub>2</sub>/I Exchange of Cyclic Diaryliodonium Salts
A straightforward
protocol for diarylannulated sulfone construction
is efficiently established via SO<sub>2</sub>/I exchange of iodoniumÂ(III)
salts. Readily available inorganic Na<sub>2</sub>S<sub>2</sub>O<sub>5</sub> was served as a safe and convenient SO<sub>2</sub> surrogate.
Diverse functionalized diarylannulated sulfones were smoothly achieved
in good to excellent yields with great functional group compatibility.
Organic light emitting diodes (OLEDs) material molecules were subsequently
established via this method in gram scale. The unsymmetrical conjugated
systems with donor-acceptor groups and π-conjugation bridges
motifs, which substantially communicate electron mobility in semiconductor
material molecules, were successfully afforded under the facile conditions
of the exchange strategy
The -607C/A Polymorphisms in Interleukin-18 Gene Promoter Contributes to Cancer Risk: Evidence from A Meta-Analysis of 22 Case-Control Studies
<div><p>Background</p><p>Several observational studies have investigated the association between -607 C/A polymorphism of IL-18 gene and cancer risk; however, the results were inconsistent. Therefore, we performed a meta-analysis to derive a more precise estimation of the association to help us better understand the relationship between -607 C/A polymorphism of IL-18 gene promoter and risk of cancer.</p> <p>Methods</p><p>A literature search was carried out using PubMed, EMBASE, and China National Knowledge Infrastructure (CNKI) database between January 1966 and February 2013. Fixed-effect and random-effect models were used to estimate the pooled odds ratio (OR) and the corresponding 95% confidence intervals (CIs).</p> <p>Results</p><p>A total of 22 case-control studies including 4100 cancer cases and 4327 controls contributed to the analysis. Significant association between -607C/A polymorphism in IL-18 gene promoter and cancer risk was observed (CA vs CC:OR =1.221, 95% CI: 1.096, 1.360; P<sub>heterogeneity</sub>=0.219; AA/CA vs. CC:OR =1.203, 95% CI: 1.057, 1.369; P<sub>heterogeneity</sub>=0.064). In the subgroup analysis by ethnicity, -607C/A polymorphism significantly increased risk of cancer among Asian population (AA/CA vs. CC:OR =1.197, 95% CI: 1.023,1.401; P<sub>heterogeneity</sub>=0.088); however, no significant association was found in Caucasian or African population. The -607C/A polymorphism was associated with a significantly increased risk of nasopharyngeal carcinoma (CA vs CC:OR =1.330, 95% CI: 1.029,1.719; P<sub>heterogeneity</sub>=0.704; AA/CA vs. CC:OR =1.323, 95% CI: 1.037,1.687; P<sub>heterogeneity</sub>=0.823) and esophageal cancer (AA/CA vs. CC:OR =1.289, 95% CI: 1.002,1.658; P<sub>heterogeneity</sub>=0.700).</p> <p>Conclusions</p><p>The present meta-analysis suggests that the -607C/A polymorphisms in IL-18 gene promoter is associated with a significantly increased risk of cancer, especially for nasopharyngeal carcinoma and esophageal cancer and in Asian population. More studies with larger sample size, well controlled confounding factors are warranted to validate this association.</p> </div
- …