Synthesis of Cinnolines and Cinnolinium Salt Derivatives by Rh(III)-Catalyzed Cascade Oxidative Coupling/Cyclization Reactions

A novel method for the synthesis of cinnolines and cinnolinium salt derivatives via Rh­(III)-catalyzed cascade oxidative coupling/cyclization reaction from Boc-arylhydrazines and alkynes has been developed. The reactions have a broad substrate scope and high stereoselectivity with readily available starting materials and provides an efficient synthetic route for this kind of compounds. A catalytically competent five-membered rhodacycle has been isolated, thus revealing a key intermediate in the catalytic cycle

Synthesis of Cinnolines and Cinnolinium Salt Derivatives by Rh(III)-Catalyzed Cascade Oxidative Coupling/Cyclization Reactions

A novel method for the synthesis of cinnolines and cinnolinium salt derivatives via Rh­(III)-catalyzed cascade oxidative coupling/cyclization reaction from Boc-arylhydrazines and alkynes has been developed. The reactions have a broad substrate scope and high stereoselectivity with readily available starting materials and provides an efficient synthetic route for this kind of compounds. A catalytically competent five-membered rhodacycle has been isolated, thus revealing a key intermediate in the catalytic cycle

Rh(III)-Catalyzed Carbocyclization of 3‑(Indolin-1-yl)-3-oxopropane­nitriles with Alkynes and Alkenes through C–H Activation

Rh­(III)-catalyzed carbocyclization reactions of 3-(indolin-1-yl)-3-oxopropane­nitriles with alkynes and alkenes have been developed to form 1,7-fused indolines through C–H activation. These reactions have a broad range of substrates and high yields. Unsymmetrical aryl–alkyl substituted alkynes proceeded smoothly with high regioselectivity. Electron-rich alkynes could undergo further oxidative coupling reaction to form polycyclic compounds. For alkenes, 1,2-dihydro-4<i>H</i>-pyrrolo­[3,2,1-<i>ij</i>]­quinolin-4-ones were formed via C­(sp²)–H bond alkenylation and C­(sp²)–H, C­(sp³)–H oxidative coupling reactions

Two new entangled complexes based on 4,4′-bis(1-imidazolyl)biphenyl: syntheses, structures, thermal and photoluminescent properties

<div><p>Two new entangled complexes, [Zn(bibp)(L¹)]·0.25H₂O (<b>1</b>) and [Co(bibp)(H₂L²)] (<b>2</b>) (bib<i>p</i> = 4,4′-bis(1-imidazolyl)biphenyl, H₂L¹ = 4,4′-(2,2′-oxybis(ethane-2,1-diyl)bis(oxy))dibenzoic acid, and H₄L² = 5,5′-(2,2′-oxybis(ethane-2,1-diyl)bis(oxy))diisophthalic acid), have been synthesized hydrothermally. Complex <b>1</b> features a new uninodal four-connected (6⁵·8) net with vertex symbol 6·6·6·6·6₂·8₂, which is different from all that exhibit uninodal four-connected (6⁵·8) nets found in the literature, including <b>cds</b>, <b>dmp</b>, <b>ict</b>, <b>mok</b>, <b>unl</b> and <b>unm</b>. Three of these nets interpenetrate. Complex <b>2</b> shows an unusual threefold 2-D → 3-D polythreaded framework, in which each 2-D wave-like net is formed by the intersection, at the shared Co nodes, of the 1-D left- and right-handed single-helical (H₂L²)²⁻ chains and the 1-D bibp <i>meso</i>-helices. Furthermore, the thermal and photoluminescent properties of <b>1</b> have also been studied.</p></div

Proteomics analysis reveals a dynamic diurnal pattern of photosynthesis-related pathways in maize leaves

<div><p>Plant leaves exhibit differentiated patterns of photosynthesis rates under diurnal light regulation. Maize leaves show a single-peak pattern without photoinhibition at midday when the light intensity is maximized. This mechanism contributes to highly efficient photosynthesis in maize leaves. To understand the molecular basis of this process, an isobaric tag for relative and absolute quantitation (iTRAQ)-based proteomics analysis was performed to reveal the dynamic pattern of proteins related to photosynthetic reactions. Steady, single-peak and double-peak protein expression patterns were discovered in maize leaves, and antenna proteins in these leaves displayed a steady pattern. In contrast, the photosystem, carbon fixation and citrate pathways were highly controlled by diurnal light intensity. Most enzymes in the limiting steps of these pathways were major sites of regulation. Thus, maize leaves optimize photosynthesis and carbon fixation outside of light harvesting to adapt to the changes in diurnal light intensity at the protein level.</p></div

Development of Quaternized Chitosan Integrated with Nanofibrous Polyacrylonitrile Mat as an Anion-Exchange Membrane

A two-phase anion-exchange membrane was prepared from quaternized chitosan (QCS) integrated with an electrospun polyacrylonitrile (PAN) scaffold by spin coating. To synthesize QCS, glycidyltrimethylammonium chloride in various amounts was introduced into the structure of CS. The characterization of the cast cross-linked QCS (CQCS) membranes by impedance spectroscopy revealed the ionic conductivity (IC) in the range of 2.8 × 10–4 to 8.2 × 10–4 S cm–1 and the degree of quaternization (DQ) of 26.4–51.0%, where the CQCS film with the DQ of 51.0% showed excellent performance. When CQCS was reinforced with a PAN fiber mat, the newly developed composite membrane demonstrated the highest IC of 34 × 10–4 S cm–1 at 80 °C, low swelling, and an almost eightfold increase in tensile strength at a fully hydrated state compared to pristine materials. Moreover, the CQCS/PAN membrane was chemically stable and revealed increasing hydroxide transport during 1 month immersion in alkaline media

The k-means clustering of differentially expressed proteins.

<p>Blue lines indicate the centroid of the k-means in each group. Red lines indicate the dynamic patterns level of proteins in each group. x-axis is the sampling time points used for proteomics analysis.</p

Expression levels of 15 selected genes that are related to photosynthesis and carbon metabolism.

<p>The expression levels of each gene are presented relative to the first time point (i.e., 6 AM). Values are the means ±standard error (SE) of three independent experiments with at least three replicates each.</p

Generation of iTRAQ proteomics data.

<p>(A) Venn diagram of identified proteins. The numbers indicate the counts of identified maize leaf proteins with differential and steady levels. (B) The distribution of the fold-changes of the identified proteins.</p

Proteins with differential levels during diurnal light cycle that are related to photosynthesis and carbon metabolism.

<p>The class of each protein was k-means clustered based on the dynamic protein levels measured at eight time points.</p