A photoinduced SET process enables the direct B−H bond activation of NHC–boranes. In contrast to common hydrogen atom transfer (HAT) strategies, this photoinduced reaction simply takes advantage of ...the beneficial redox potentials of NHC–boranes, thus obviating the need for extra radical initiators. The resulting NHC–boryl radical was used for the borylation of a wide range of α‐trifluoromethylalkenes and alkenes with diverse electronic and structural features, providing facile access to highly functionalized borylated molecules. Labeling and photoquenching experiments provide insight into the mechanism of this photoinduced SET pathway.
A photoinduced SET process enables the direct B−H bond activation of NHC–boranes. The resulting NHC–boryl radical was used for the borylation of a wide range of α‐trifluoromethylalkenes and alkenes with diverse electronic and structural features, providing facile access to highly functionalized borylated molecules.
A metal‐free photosensitized protocol for regioselective diamination of alkene feedstocks over a single step was developed based on the rationally designed bifunctional diamination reagent, thus ...affording a range of differentially protected 1,2‐diamines in moderate to high yields. Mechanistic studies reveal that the reaction is initiated with a triplet‐triplet energy transfer between thioxanthone catalyst and diamination reagent, followed by fragmentation to simultaneously generate long‐lived iminyl radical and transient amidyl radical. The excellent regioselectivity presumably stems from the large reactivity difference between two different N‐centered radical species. This protocol is characterized by excellent regioselectivity, broad functional group tolerance, and mild reaction conditions, which would enrich the diversity and versatility of facilitate the diversity‐oriented synthesis of 1,2‐diamine‐containing complex molecule scaffolds.
A metal‐free, photosensitized regioselective diamination of alkene is reported. The keys to this advance are: 1) rational design of bifunctional diamination reagent, 2) simultaneous generation of long‐lived iminyl radical and transient amidyl radical with significantly differed reactivities, and 3) involvement of photoinduced energy transfer reaction mode.
A photoinduced, phosphoranyl radical-mediated protocol for the direct N–O cleavage of strained cycloketone oximes via a polar/SET crossover process was developed for the first time. This ...visible-light-driven direct N–O activation mode for oxime offers beneficial features such as streamlined synthetic process and versatile photochemical reactivities. Consequently, the alkenes and α-trifluoromethyl alkenes with varied electronic and structural features acted as competent radical receptors in this protocol, enabling facile accesses to a range of elongated cyano and/or gem-difluoroalkene-bearing compounds.
The oriental armyworm,
(Walker), is a well-known nocturnal migratory pest that relies on its exceptional nocturnal vision for navigation during long-distance flights. In this study, we investigated ...the ultrastructure of the compound eyes of adult
using transmission electron microscopy and quantitatively evaluated adaptational changes in the retina under light and dark conditions. The compound eyes of
are superposition eyes with a clear zone. The retina shows remarkable anatomical differences under light and dark adaptation, primarily characterized by distinct patterns of rhabdoms within the clear zone: the rhabdoms are nearly absent under light adaptation, but become more voluminous under dark adaptation. In the distal, middle, and proximal sections of the clear zone, the cross-sectional areas of retinulae and rhabdoms, as well as the rhabdom occupation ratio, are significantly larger under dark adaptation than under light adaptation. Conversely, the opposite trend is observed beneath the clear zone. These results indicate remarkable plasticity in the
retina throughout a normal daily cycle, providing a theoretical basis for improving searchlight and ground light trap techniques for the management of this migratory species.
An unprecedented photoredox‐catalyzed phosphine‐mediated deoxygenation of hexafluoroacetone hydrate was established to accomplish the hydroxylpolyfluoroalkylation of electron‐deficient alkenes. A ...range of bis(trifluoromethyl)carbinols were facilely accessed by using readily available hexafluoroacetone hydrate, instead of toxic gaseous hexafluoroacetone. A range of electron‐deficient alkenes are tolerated, giving the corresponding hydro‐hydroxylpolyfluoroalkylated products in moderate to high yields. Remarkable features of this synthetic strategy include operational simplicity, mild reaction conditions, excellent regioselectivity, and broad functional group tolerance. The success of this strategy relies on the delicate utilization of aldehyde/ketone‐gem‐diol intrinsic equilibrium, which offers an innovated open‐shell pathway for the assembly of synthetically challenging polyfluoroalkylated scaffolds.
The hydroxypolyfluoroalkylation of alkenes is reported, wherein the intrinsic aldehyde/ketone‐gem‐diol equilibrium and photocatalytic phosphine‐mediated deoxygenation play key roles. A range of electron‐deficient alkenes are compatible in this transformation, thus leading to structurally varied bis(trifluoromethyl)carbinols in moderate to excellent yields.
A facile and diversified synthesis of functionalized CF2-containing benzoxepine derivatives via photoredox catalysis was achieved in this work. This novel protocol features broad substrate scope, ...mild reaction conditions, operational simplicity, easy scale-up, and versatile derivatization, which would facilitate its practical and broad applications in the construction of valuable and synthetically challenging heterocycles.
High salt is positively associated with the risk of many diseases. However, little is known about the mechanisms. Here we showed that high salt increased proinflammatory molecules, while decreased ...anti-inflammatory and proendocytic molecules in both human and mouse macrophages. High salt also potentiated lipopolysaccharide-induced macrophage activation and suppressed interleukin 4-induced macrophage activation. High salt induced the proinflammatory aspects by activating p38/cFos and/or Erk1/2/cFos pathways, while inhibited the anti-inflammatory and proendocytic aspects by Erk1/2/signal transducer and activator of transcription 6 pathway. Consistent with the in vitro results, high-salt diet increased proinflammatory gene expression of mouse alveolar macrophages. In mouse models of acute lung injury, high-salt diet aggravated lipopolysaccharide-induced pulmonary macrophage activation and inflammation in lungs. These results identify a novel macrophage activation state, M(Na), and high salt as a potential environmental risk factor for lung inflammation through the induction of M(Na).
A catalyst-free strategy for regioselective hydroxydifluoroalkylation of alkenes with alkyl bromides was developed, affording a series of difluoroalkylated tertiary alcohols in moderate to good ...yields. This photocatalyst-free protocol shows broad substrate scope under mild conditions. Moreover, mechanistic studies revealed that a newly identified electron donor–acceptor complex is crucial to this transformation.
Introduction
Polygoni Orientalis Fructus (POF) is a clinically effective Chinese medicine. Raw POF (RPOF) and POF Tostus (POFT) are used separately in clinics. However, incomplete progress has been ...made on quality control.
Objective
To establish a comprehensive method for quality assessment of RPOF and POFT and to discriminate these two varieties.
Methodology
High‐performance liquid chromatography combined with the diode array detector (HPLC‐DAD) methods were developed for fingerprinting and quantitative analysis of seven major compounds in RPOF and POFT, and the main components were determined by HPLC‐DAD coupled with Fourier‐transform ion cyclotron resonance‐mass spectrometry. Chemometric approaches were performed to discriminate RPOF and POFT and to screen discriminatory components.
Results
Fingerprints were established and 12 common peaks were identified, cannabisin G and cannabisin E were firstly identified from POF. In quantitative analysis, all analytes showed good regression (R > 0.9996) within test ranges and the recovery of the method was in the range 96.6–104.3%. Fingerprints in conjunction with similarity analysis and hierarchical clustering analysis (HCA) demonstrated the consistent quality of RPOF and showed a clear discrimination between RPOF and POFT. Principal component analysis, partial least‐squares discriminant analysis, and heatmap‐HCA on quantitative data not only gave a clear differentiation between RPOF and POFT, but they also suggested that quercetin, 3,5,7‐trihydroxychromone, and N‐trans‐feruloyltyramine acted as the main factors responsible for the sample differences.
Conclusions
Chromatographic analysis in combination with chemometric analysis provides a simple and reliable method of comparing and evaluating the qualities of RPOF and POFT.
The purpose of this work is to establish a simple and acceptable method for quality assessment of raw Polygoni Orientalis Fructus (RPOF) and Polygoni Orientalis Fructus Tostus (POFT) and to discriminate these two varieties by using chemical fingerprinting and simultaneous determination of seven major components coupled with chemometric analyses. The chromatographic methods were established. The chromatographic analysis gave a clear differentiation between RPOF and POFT and filtered out three components which acted as the main factors responsible for the samples differences.
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