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https://www.readbyqxmd.com/read/30318544/nickel-ii-catalyzed-enantioselective-%C3%AE-alkylation-of-%C3%AE-ketoamides-with-phenyliodonium-ylide-via-a-radical-process
#1
Jing Guo, Xiaohua Liu, Changqiang He, Fei Tan, Shunxi Dong, Xiaoming Feng
Chiral Lewis acid-promoted enantioselective α-alkylation of β-ketoamides with phenyliodonium ylide was developed. In the presence of a chiral N,N'-dioxide/Ni(ii) complex, the corresponding 1,4-dicarbonyl compounds were obtained with good results (up to 91% yield and 97% ee). Control experiments and EPR studies supported a radical process.
October 15, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/30310608/visualization-of-methylglyoxal-in-living-cells-and-diabetic-mice-model-with-a-1-8-naphthalimide-based-two-photon-fluorescent-probe
#2
Mingwang Yang, Jiangli Fan, Junwei Zhang, Jianjun Du, Xiaojun Peng
Methylglyoxal (MGO), a dicarbonyl metabolite, is the most studied precursor of advanced glycation end-products (AGEs) and its elevated levels have also been associated with various pathologies. Hence, the development of effective methods for monitoring MGO in live cells and in vivo is of great importance for ascertaining the onset and progress of related diseases. Herein, we designed and synthesized an endoplasmic reticulum-targeting two-photon fluorescent probe called NI-OPD for the detection of MGO with high selectivity, sensitivity, and hypotoxicity...
September 7, 2018: Chemical Science
https://www.readbyqxmd.com/read/30309598/structure-activity-relationship-of-procyanidins-on-advanced-glycation-end-products-formation-and-corresponding-mechanisms
#3
Yuanyuan Chen, Shimiao Tang, Yashu Chen, Roujie Zhang, Mengzhou Zhou, Chao Wang, Nianjie Feng, Qian Wu
Nonenzymatic glycosylation (NEG) can generate advanced glycation end products (AGEs) and its intermediates α-dicarbonyl compounds, which contribute to the risk of diabetes. This study investigated the anti-glycation mechanisms and structure-activity relationship of (+)-catechin (CC) and (-)-epicatechin (EC). The results showed that the effect of CC on inhibiting AGEs was significantly better than that of EC (p < 0.05). By exploring the mechanism, we found that there was no significant difference in the ability of CC and EC to capture α-dicarbonyl compounds...
January 30, 2019: Food Chemistry
https://www.readbyqxmd.com/read/30306985/titanium-thiosalicylate-complexes-functional-metalloligands-for-the-construction-of-redox-active-heterometallic-architectures
#4
Rosa Fandos, Sonia Bruña, Carolina Hernández, Antonio Otero, Ana Rodríguez, María José Ruiz, Pilar Terreros, Isabel Cuadrado
The titanium complex [TiCp*(thiosal)(thiosalH)] (1) has been synthesised by reaction of [TiCp*Me3], Cp* = η5-C5Me5, with thiosalicylic acid (H2thiosal). Complex 1 reacts with [M(μ-OH)(COD)]2 (M = Rh, Ir) to yield the corresponding early-late heterobimetallic complexes [TiCp*(thiosal)2M(COD)] (M = Rh (2); Ir (3)). Carbon monoxide replaces the COD ligand in 2 and 3 leading to the respective dicarbonyl complexes [TiCp*(thiosal)2M(CO)2] (M = Rh (4); Ir (5)). Compound 4 reacts with PPh3 to yield the monocarbonyl derivative [TiCp*(thiosal)2Rh(CO)(PPh3)] (6)...
October 11, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/30296489/isolevuglandins-and-cardiovascular-disease
#5
REVIEW
Sean S Davies, Linda S May-Zhang
Isolevuglandins are 4-ketoaldehydes formed by peroxidation of arachidonic acid. Isolevuglandins react rapidly with primary amines including the lysyl residues of proteins to form irreversible covalent modifications. This review highlights evidence for the potential role of isolevuglandin modification in the disease processes, especially atherosclerosis, and some of the tools including small molecule dicarbonyl scavengers utilized to assess their contributions to disease.
October 5, 2018: Prostaglandins & Other Lipid Mediators
https://www.readbyqxmd.com/read/30290026/synthesis-structure-and-nickel-carbonyl-complexes-of-dialkylterphenyl-phosphines
#6
Ernesto Carmona, Mario Marín, Juan J Moreno, Carlos Navarro-Gilabert, Celia Maya, Riccardo Peloso, M Carmen Nicasio, Eleuterio Álvarez
We describe the experimental and computational characterization of a series of dialkylterphenyl phosphines, PR2Ar' (Figure 2). Molecules of composition PR2ArDtbp2, for R = Me, Et, iPr, c-C5H9 and c-C6H11, are accompanied by five PR2Ar' phosphines containing the bulky alkyl groups iPr, c-C5H9 or c-C6H11, in combination with Ar' = ArXyl2, ArXyl'2, or ArPh2 (L1-L10). Steric and electronic parameters have been determined computationally and from IR and X-ray data obtained for the phosphines and for some derivatives, including tricarbonyl and dicarbonyl nickel complexes, Ni(CO)3(PR2Ar') and Ni(CO)2(PR2Ar')...
October 5, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/30289146/synthesis-of-highly-rigid-phosphine-oxazoline-ligands-for-palladium-catalyzed-asymmetric-allylic-alkylation
#7
Zhongxuan Qiu, Rui Sun, Dawei Teng
A highly rigid spiro phosphine-oxazoline ligand skeleton with a spirocarbon stereogenic center was developed from 7-bromo-1-indanone. The catalytic performance of the ligand was demonstrated in palladium-catalyzed asymmetric allylic alkylation. Under optimized conditions, high yields (up to 99%) and enantioselectivities (up to 99.9% ee) were obtained for reactions of 1,3-diphenylallyl acetates and symmetrical 1,3-dicarbonyl substrates.
October 5, 2018: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/30278300/silver-catalyzed-regio-and-stereoselective-formal-carbene-insertion-into-unstrained-c-c-%C3%AF-bonds-of-1-3-dicarbonyls
#8
Zhaohong Liu, Xinyu Zhang, Matteo Virelli, Giuseppe Zanoni, Edward A Anderson, Xihe Bi
A regio- and stereoselective silver-catalyzed formal carbene insertion into 1,3-dicarbonyls has been developed, using N-nosylhydrazones as diazo surrogates. Two new C-C bonds are constructed at the carbenic carbon center through the selective cleavage of the C-C(=O) σ-bond of acyclic 1,3-dicarbonyls, enabling the preparation of various synthetically useful polysubstituted γ-diketones, γ-ketoesters, and γ-ketoamides in high yields. The in situ formation of a donor-acceptor cyclopropane, via reaction of the enolate of the 1,3-dicarbonyl with an electrophilic silver carbenoid, is proposed as a key process in the catalytic cycle...
September 18, 2018: iScience
https://www.readbyqxmd.com/read/30264840/preparation-of-polysubstituted-dihydrofurans-through-a-phi-oac-2-promoted-haloenolcyclization-of-olefinic-dicarbonyl-compounds
#9
Ji Liu, Qing-Yun Liu, Xing-Xiao Fang, Gong-Qing Liu, Yong Ling
A metal-free cyclization of olefinic dicarbonyl compounds for the synthesis of various 5-halomethyl-4,5-dihydrofurans is presented. Using (diacetoxyiodo)benzene as the reaction promoter and halotrimethylsilane as the halogen source, the intramolecular haloenolcyclization of the 2-allyl-1,3-dicarbonyl compounds smoothly proceeded, leading to the corresponding 5-halomethyl-4,5-dihydrofurans in good to excellent isolated yields. Moreover, the resulting 5-iodomethyl products could be converted to functionalized furans in almost quantitative yields by treatment with DBU followed by acid-catalyzed rearrangement...
October 17, 2018: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/30257468/1-n-acylamino-alkyltriarylphosphonium-salts-with-weakened-c-%C3%AE-p%C3%A2-%C2%BA-bond-strength-synthetic-applications
#10
Jakub Adamek, Anna Węgrzyk, Justyna Kończewicz, Krzysztof Walczak, Karol Erfurt
The α-amidoalkylating properties of 1-( N -acylamino)alkyltriarylphosphonium salts with weakened Cα -P⁺ bond strength are discussed and examined. It is demonstrated that such type of phosphonium salts reacts smoothly with a diverse array of carbon- and heteroatom-based nucleophiles, including 1-morpholinocyclohexene, 1,3-dicarbonyl compounds, benzotriazole sodium salt, p -toluenesulfinate sodium salt, benzylamine, triarylphosphines, and other P-nucleophiles. Reactions are conducted at room temperature, in a short time (5⁻15 min) and mostly without catalysts...
September 25, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/30256466/enantioselective-electrophilic-cyanation-of-boron-enolates-scope-and-mechanistic-studies
#11
Takaya Nagata, Atsuko Tamaki, Kensuke Kiyokawa, Ryosuke Tsutsumi, Masahiro Yamanaka, Satoshi Minakata
Chiral β-ketonitriles bearing a stereogenic carbon center at the α-position are an important class of compounds, many of which serve as useful synthetic intermediates for the preparation of chiral 1,3-aminoalcohols, β-hydroxy nitriles and related derivatives. Although the enantioselective electrophilic cyanation of enolate equivalents is one of the most promising approaches for the synthesis of chiral β-ketonitriles, the available methods are largely limited to reactions of 1,3-dicarbonyl compounds. Herein, we report on enantioselective electrophilic cyanation of boron enolates, which are readily prepared from α,β-unsaturated ketones and diisopinocampheylborane (Ipc2BH), to afford chiral β-ketonitriles with a high level of enantioselectivity...
September 26, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/30251870/silver-catalyzed-radical-cascade-cyclization-toward-1-5-1-3-dicarbonyl-heterocycles-an-atom-step-economical-strategy-leading-to-chromenopyridines-and-isoxazole-pyrazole-containing-chroman-4-ones
#12
Hao Hu, Xiaolan Chen, Kai Sun, Junchao Wang, Yan Liu, Hui Liu, Lulu Fan, Bing Yu, Yuanqiang Sun, Lingbo Qu, Yufen Zhao
A novel and convenient silver-catalyzed radical cascade cyclization toward a large variety of 1,5-/1,3-dicarbonyl heterocycles containing a chroman-4-one, indanone, or 2,3-dihydroquinolin-4(1 H)-one moiety was developed, by reacting various 2-functionalized benzaldehydes, including 2-allyloxy benzaldehydes, 2-allyl benzaldehyde, and 2-N(Ts)CH2 -CH═CH2 substituted benzaldehyde, with 1,3-dicarbonyl compounds in the presence of AgNO3 /K2 S2 O8 in one pot under mild reaction conditions. The newly obtained 1,5-/1,3-dicarbonyl-containing heterocycles were further used directly to synthesize more structurally diverse polyheterocycles, mainly including chromenopyridines as well as isoxazole- or pyrazole-containing chroman-4-ones...
October 5, 2018: Organic Letters
https://www.readbyqxmd.com/read/30250846/dicarbonyl-stress-and-glyoxalase-1-in-skeletal-muscle-implications-for-insulin-resistance-and-type-2-diabetes
#13
REVIEW
Jacob T Mey, Jacob M Haus
Glyoxalase-1 (GLO1) is a ubiquitously expressed cytosolic protein which plays a role in the natural maintenance of cellular health and is abundantly expressed in human skeletal muscle. A consequence of reduced GLO1 protein expression is cellular dicarbonyl stress, which is elevated in obesity, insulin resistance and type 2 diabetes (T2DM). Both in vitro and pre-clinical models suggest dicarbonyl stress per se induces insulin resistance and is prevented by GLO1 overexpression, implicating a potential role for GLO1 therapy in insulin resistance and type 2 diabetes (T2DM)...
2018: Frontiers in Cardiovascular Medicine
https://www.readbyqxmd.com/read/30246826/metal-free-direct-c-arylation-of-1-3-dicarbonyl-compounds-and-ethyl-cyanoacetate-a-platform-to-access-diverse-arrays-of-meta-functionalized-phenols
#14
Neha Taneja, Rama Krishna Peddinti
A base mediated, highly convenient strategy for the direct C-arylation of 1,3-dicarbonyls and cyanoacetate with various phenol derivatives as aryl partners is presented. The present work excels in forming a C-C bond at the meta-position of the phenols, which is traditionally challenging to functionalize. This protocol further leads the way to have scalable, straightforward access to phenol assimilated heterocycles which have powerful applications both in synthetic chemistry and medicinal research.
October 9, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/30236745/formation-of-allysine-in-%C3%AE-lactoglobulin-and-myofibrillar-proteins-by-glyoxal-and-methylglyoxal-impact-on-water-holding-capacity-and-in-vitro-digestibility
#15
Carolina Luna, Mario Estévez
The ability of α-dicarbonyls, glyoxal (GO) and methyl-glyoxal (MGO) (2 M), to induce the formation of allysine in β-lactoglubulin (LAC), and myofibrillar proteins (MP) (2 mg/mL) during incubation at 80 °C for 48 h, was studied. Both GO and MGO induced the formation of allysine in all tested proteins with GO being more reactive (23.8 and 8.6 nmoles/mg protein in LAC and MP respectively after 6 h) than MGO (2.6 and 3.1 nmoles/mg protein at the same sampling point). LAC seemed to be more susceptible to the glycation reactions than MP...
January 15, 2019: Food Chemistry
https://www.readbyqxmd.com/read/30236734/galangin-inhibits-%C3%AE-glucosidase-activity-and-formation-of-non-enzymatic-glycation-products
#16
Li Zeng, Huafang Ding, Xing Hu, Guowen Zhang, Deming Gong
Inhibition of α-glucosidase and non-enzymatic glycation is considered as an effective approach to treat type 2 diabetes. Herein, multispectroscopic techniques and molecular docking analysis were used to investigate the inhibition of galangin on α-glucosidase and non-enzymatic glycation. Galangin showed a reversible inhibition on α-glucosidase activity in a mixed-type manner through a monophasic kinetic process, and induced the fluorescence quenching and conformational changes of α-glucosidase by forming α-glucosidase-galgangin complex...
January 15, 2019: Food Chemistry
https://www.readbyqxmd.com/read/30234224/atom-economic-synthesis-of-cyclobuta-a-naphthalen-4-ols-via-a-base-promoted-2-2-cycloaddition-1-6-nucleophilic-addition-cascade
#17
Jia-Yin Wang, Feng-Lie Xie, Jian-Qiang Hu, Shi-Zhao Yang, You-Jian Wang, Wen-Juan Hao, Shu-Jiang Tu, Bo Jiang
A first atom-economic [2 + 2] cycloaddition/1,6-conjugate addition cascade of yne-allenones with C-nucleophiles including 1,3-dicarbonyls and α,α-dicyanoolefins under base-promoted conditions has been established, enabling the direct construction of C(sp3)-C(sp3) bonds to generate cyclobuta[a]naphthalen-1-ols with generally good yields. These resulting products have a cyclobutene unit that contains both an aryl and alkyl group.
October 10, 2018: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/30217477/effects-of-methylglyoxal-on-rankl-induced-osteoclast-differentiation-in-raw264-7-cells
#18
Kwang Sik Suh, Suk Chon, Woon-Won Jung, Eun Mi Choi
Methylglyoxal (MG) is a reactive dicarbonyl compound produced by glycolytic processing, which has been identified as a precursor of advanced glycation end products. Elevated MG levels in patients with diabetes are believed to contribute to diabetic complications, including bone defects. The objective of this study was to evaluate the effect of MG on RANKL-induced osteoclast differentiation in RAW264.7 cells, a murine macrophage cell line. RAW264.7 cells were cultured in medium containing 50 ng/mL RANKL and different concentrations of MG...
September 12, 2018: Chemico-biological Interactions
https://www.readbyqxmd.com/read/30192154/visible-light-induced-intermolecular-dearomative-cyclization-of-2-bromo-1-3-dicarbonyl-compounds-and-alkynes-synthesis-of-spiro-4-5-deca-1-6-9-trien-8-ones
#19
Wuheng Dong, Yao Yuan, Xiaoshuang Gao, Miladili Keranmu, Wanfang Li, Xiaomin Xie, Zhaoguo Zhang
A visible-light-induced photocatalytic intermolecular dearomative cyclization of 2-bromo-1,3-dicarbonyl compounds and alkynes afforded biologically important spirocarbocycle structures in moderate to good yields via a 5-exo-dig radical cyclization under mild reaction conditions. A 5.0 mmol scale dearomatization reaction proceeded smoothly with 95% yield even when the catalyst loading was reduced to 0.1 mol %, suggesting that this method was suitable for large-scale synthesis.
September 21, 2018: Organic Letters
https://www.readbyqxmd.com/read/30188133/substitution-controlled-selective-formation-of-hexahydrobenz-e-isoindoles-and-3-benzazepines-via-in-otf-3-catalyzed-tandem-annulations
#20
Siyang Xing, Nan Gu, Xin Wang, Jingyi Liu, Chunyan Xing, Kui Wang, Bolin Zhu
A dramatic N-substituent controlled tandem annulation of 2-(2-(2-bromoethyl)phenyl)-1-sulfonylaziridines with 1,3-dicarbonyl compounds has been developed. When the N-substituent was a 4-methylbenzenesulfonyl group (Ts), sequential ring opening of aziridines, nucleophilic substitution, and lactamization took place to provide a series of hexahydrobenz[ e]isoindole compounds in good yields with good diastereoselectivities. By contrast, 3-benzazepine compounds were afforded in good yields via ring opening of aziridines and nucleophilic substitution when the N-substituent was the 4-nitrobenzenesulfonyl group (Ns)...
September 21, 2018: Organic Letters
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