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Heterocyclic chemistry

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https://www.readbyqxmd.com/read/28325143/synthesis-and-characterization-of-a-new-benzo-indole-derivative-with-apoptotic-activity-against-colon-cancer-cells
#1
Fatemeh Hajiaghaalipou, Fadhil Lafta Faraj, Elham Bagheri, Hamid Khaledi, Hapipah Mohd Ali, Nazia Abdul Majid, Mahmood Ameen Abdulla
BACKGROUND: Colorectal cancer is the third most common form of cancer in both men and women around the world. The chemistry and biological study of heterocyclic compounds have been an interesting area for a long time in pharmaceutical and medicinal chemistry. METHODS: A new synthetic compound, 2-(1,1-Dimethyl-1,3-dihydro-benzo[e]indol-2-ylidene)-3-(2-hydroxy-phenylimino)-propionaldehyde, abbreviated as DBID has been synthesized by reaction of 2-(1,1-Dimethyl-1,3-dihydro-benzo[e]indol-2-ylidene)-malonaldehyde with 2-aminophenol...
March 20, 2017: Current Pharmaceutical Design
https://www.readbyqxmd.com/read/28298102/rotational-spectra-of-two-six-membered-heterocyclic-n-methyl-piperidinol-compounds-conformations-by-oh-rotation-n-methyl-inversion-and-ring-puckering
#2
Javix Thomas, Eric Mariona, Yunjie Xu
Rotational spectra of two nitrogen containing six-membered heterocycles which are commonly used in syntheses of pharmaceuticals, namely, N-methyl-3-piperidinol (NMP3) and N-methyl-4-piperidinol (NMP4), were measured using a broadband chirped pulse and a cavity based Fourier transform microwave spectrometer. The possible conformers due to the OH rotation, N-methyl inversion, and ring puckering were investigated theoretically for these two heterocycles. The substituent position of the hydroxyl group with respective to the N atom in the heterocyclic ring has a strong influence on the preferred conformations...
March 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28276611/transition-metal-catalyzed-utilization-of-methanol-as-c1-source-in-organic-synthesis
#3
Jagadeesh Rajenahally, Kishore Natte, Helfried Neumann, Matthias Beller
Methanol represents one of the privileged and widespread platform chemicals, which is used in many science sectors such as chemistry, biology, medicine and energy. This essential alcohol serves as common solvent, cost-effective reagent and sustainable feedstock for value-added chemicals, pharmaceuticals and materials. Among different applications, the utilization of methanol as C1 source for the formation of carbon-carbon, carbon-nitrogen and carbon-oxygen bonds continues to be important in organic synthesis and drug discovery...
March 9, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28272608/new-trends-in-the-functionalization-of-metallic-gold-from-organosulfur-ligands-to-n-heterocyclic-carbenes
#4
Sabrina Engel, Eva-Corinna Fritz, Bart Jan Ravoo
In this Tutorial Review, we describe the development of new ligands for functionalizing and stabilizing metallic gold in the form of planar gold surfaces and gold nanoparticles (NPs). Starting from the state-of-the-art of organosulfur ligands, we describe the gold-sulfur bond formation and the nature of the resulting interface. In addition, we explain methods to prepare ordered monolayers on planar surfaces and stable ligand shells around NPs, illustrating important pioneering studies and examples of current research...
March 8, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/28271713/evidence-of-oxygen-activation-in-the-reaction-between-an-n-heterocyclic-carbene-and-m3n-ih-7-c80-an-unexpected-method-of-steric-hindrance-release
#5
Muqing Chen, Wangqiang Shen, Ping Peng, Lipiao Bao, Shasha Zhao, Yunpeng Xie, Peng Jin, Hongyun Fang, Fang-Fang Li, Xing Lu
We herein demonstrate for the first time the unexpected oxygen-involving reaction between M3N@Ih(7)-C80 (M = Sc, Lu) and 1,3-bis(diisopropylphenyl)imidazol-2-ylene (1). By introducing a tiny amount of oxygen into the reaction, unprecedented products (2a for Sc3N@C80 and 3a for Lu3N@C80) with the normal carbene center C2 singly bonded to a triple hexagonal junction (THJ) cage carbon together with an oxygen atom bridging the same THJ carbon atom and a neighboring carbon atom forming an epoxy structure are obtained...
March 13, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28263016/merging-n-heterocyclic-carbene-catalysis-and-single-electron-transfer-a-new-strategy-for-asymmetric-transformations
#6
Kun Zhao, Dieter Enders
Radical chemistry meets NHCs: NHC catalysis and single electron oxidants have been merged in several transformations, allowing the synthesis of useful β-hydroxy esters, cyclopentanones, and spirocyclic-γ-lactones in a highly stereoselective manner. The key step is the oxidation of the NHC homoenolate equivalent to a radical species via a single-electron transfer process.
March 6, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28261889/site-selective-modification-of-proteins-with-oxetanes
#7
Omar Boutureira, Nuria Martínez-Sáez, Kevin M Brindle, André A Neves, Francisco Corzana, Gonçalo J L Bernardes
Oxetanes are 4-membered ring oxygen heterocycles that are advantageously used in medicinal chemistry as modulators of physicochemical properties of small molecules. Here, we present a simple methodology for the ready incorporation of oxetanes into proteins through chemoselective alkylation of cysteine. We demonstrate a broad substrate scope by reacting proteins used as apoptotic markers and in drug formulation, and a therapeutic antibody with a series of 3-oxetane bromides, enabling the identification of novel handles (S-to-S/N rigid, non-aromatic, and soluble linker) and reactivity modes (temporary cysteine protecting group), while maintaining their intrinsic activity...
March 5, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28256015/highly-electron-rich-%C3%AE-diketiminato-systems-synthesis-and-coordination-chemistry-of-amino-functionalized-n-nacnac-ligands
#8
Dinh Cao Huan Do, Ailsa Keyser, Andrey Protchenko, Brant Maitland, Indrek Pernik, Haoyu Niu, Eugene Kolychev, Arnab Rit, Dragoslav Vidovic, Andreas Stasch, Cameron Jones, Simon Aldridge
The synthesis of a class of electron-rich amino-functionalized β-diketiminato (N-nacnac) ligands is reported, with two synthetic methodologies having been developed for systems bearing backbone NMe2 or NEt2 groups and a range of N-bound aryl substituents. In contrast to their (Nacnac)H counterparts, the structures of the protio-ligands feature the bis(imine) tautomer and a backbone CH2 group. Direct metallation with lithium, magnesium or aluminium alkyls allows access to the respective metal complexes via deprotonation of the methylene function; in each case X-ray structures are consistent with a delocalized imino-amide ligand description...
March 2, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28252145/b-b-bond-activation-and-nhc-ring-expansion-reactions-of-diboron-4-compounds-and-accurate-molecular-structures-of-b2-nme2-4-b2eg2-b2neop2-and-b2pin2
#9
Martin Eck, Sabrina Würtemberger-Pietsch, Antonius Eichhorn, Johannes H J Berthel, Rüdiger Bertermann, Ursula S D Paul, Heidi Schneider, Alexandra Friedrich, Christian Kleeberg, Udo Radius, Todd B Marder
In this detailed study we report on the structures of the widely employed diboron(4) compounds bis(pinacolato)diboron (B2pin2) and bis(neopentyl glycolato)diboron (B2neop2), as well as bis(ethylene glycolato)diboron (B2eg2) and tetrakis(dimethylamino)diboron (B2(NMe2)4), and their reactivity, along with that of bis(catecholato)diboron (B2cat2) with backbone saturated and backbone unsaturared N-heterocyclic carbenes (NHCs) of different steric demand. Depending on the nature of the diboron(4) compound and the NHC used, Lewis-acid/Lewis-base adducts or NHC ring-expansion products stemming from B-B and C-N bond activation have been observed...
March 14, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28247903/iridium-catalyzed-acceptor-acceptor-carbene-insertion-into-n-h-bonds-in-water
#10
Kankanala Ramakrishna, Chinnappan Sivasankar
The chemistry of A and D/A carbenes (D and A are donor and acceptor groups, respectively) is known to a great extent in the literature. Nevertheless the chemistry of the A/A class of carbenes is less explored, although the A/A class of carbenes is more important in natural product synthesis. The known catalysts for A/A carbene chemistry are also less in number and are found to be efficient only in typical organic solvents. These limitations prompted us to search for new catalysts and environmentally benign reaction conditions for the A/A class of carbenes...
March 1, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28240166/synthesis-of-medicinally-privileged-heterocycles-through-dielectric-heating
#11
Debasish Bandyopadhyay, Bimal K Banik
This review summarizes the potential application of microwave irradiation (dielectric heating) to synthesize biologically important heterocyclic small molecules in the recent past. A huge number of heterocyclic compounds are present in various natural sources like plant, marine microbe or other organisms and many of them possess unique biological activity. In addition to nature-derived heterocyclic compounds, a large number of synthetic heterocycles are being used as medicines. This review describes the relevant recent examples of microwave irradiation to accomplish various chemical transformations accelerated by a variety of catalysts which include, but not limited to, Lewis acids, other metal containing catalysts, organocatalysts, heterogeneous catalysts, phase-transfer catalysts, solid-supported catalysts, inorganic catalysts (bases, acids and salts) and so on...
February 23, 2017: Current Medicinal Chemistry
https://www.readbyqxmd.com/read/28231521/therapeutic-journey-of-2-4-thiazolidinediones-as-a-versatile-scaffold-an-insight-into-structure-activity-relationship
#12
REVIEW
Mohd Javed Naim, Md Jahangir Alam, Shujauddin Ahmad, Farah Nawaz, Neelima Shrivastava, Meeta Sahu, Ozair Alam
Thiazolidinedione is an important heterocyclic ring system, a pharmacophore and a privileged scaffold in medicinal chemistry; is a derivative of thiazolidine ring which came into existence for its role as antihyperglycemic agent and a specific ligand of PPAR's (Peroxisome proliferator activated receptor). Exhaustive research has led to determination of its vast biological profile with wide range of therapeutic applications. This review covers recent pharmacological advancements of thiazolidinedione moiety along with structure activity relationship so as to provide better correlation among different structures and their receptor interactions...
March 31, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28228852/3d-printed-fluidics-with-embedded-analytic-functionality-for-automated-reaction-optimisation
#13
Andrew J Capel, Andrew Wright, Matthew J Harding, George W Weaver, Yuqi Li, Russell A Harris, Steve Edmondson, Ruth D Goodridge, Steven D R Christie
Additive manufacturing or '3D printing' is being developed as a novel manufacturing process for the production of bespoke micro- and milliscale fluidic devices. When coupled with online monitoring and optimisation software, this offers an advanced, customised method for performing automated chemical synthesis. This paper reports the use of two additive manufacturing processes, stereolithography and selective laser melting, to create multifunctional fluidic devices with embedded reaction monitoring capability...
2017: Beilstein Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28222606/flexible-porphyrinoids
#14
Bartosz Szyszko, Michał J Białek, Ewa Pacholska-Dudziak, Lechosław Latos-Grażyński
This review underscores the conformational flexibility of porphyrinoids, a unique class of functional molecules, starting from the smallest triphyrins(1.1.1) via [18]porphyrins(1.1.1.1) and concluding with a variety of expanded porphyrinoids and heteroporphyrinoids, including the enormous [96]tetracosaphyrin(1.0.1.0.1.0.1.0.1.0.1.0.1.0.1.0.1.0.1.0.1.0.1.0). The specific flexibility of porphyrinoids has been documented as instrumental in the designing or redesigning of macrocyclic frames, particularly in the search for adjustable platforms for coordination or organometallic chemistry, anion binding, or mechanistic switches in molecular devices...
February 22, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/28220966/nhc-based-tri-organyl-zn-alkyl-cations-synthesis-structure-isomerization-for-improved-stability-and-use-in-co2-functionalization
#15
Samuel Dagorne
Tri-organyl and tri-coordinate N-heterocyclic carbene Zn-NHC alkyl cations (nNHC)2Zn-Me+ (nNHC = C2-bonded-IMes/-IDipp; 3+ and 4+) were first synthesized and structurally characterized via ionization of the corresponding neutral precursors (NHC)ZnMe2 with [Ph3C][B(C6F5)4] in the presence of 1 equiv. of free NHC. Cations 3+-5+ are the first Zn cations of the type Zn(C)(C')(C'')+ (C, C', C'' = σ-donor carbyl ligand). While cation (nIMes)2Zn-Me+ (3+) is stable, its sterically congested analogue (nIDipp)2Zn-Me+ (4+) readily undergoes a nNHC-to-aNHC isomerization in the presence of THF or IDipp to afford the more thermodynamically stable (aDipp)(nIDipp)Zn-Me+ (aIDipp = C5-bonded IDipp, 5+), reflecting the adaptable-to-sterics coordination chemistry of these cations for improved stability...
February 21, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28218492/nhc-catalyzed-metathesis-and-phosphorylation-reactions-of-disulfides-development-and-mechanistic-insights
#16
Reece Douglas Crocker, Mohanad A Hussein, Junming Ho, Thanh Vinh Nguyen
The development of efficient methods for the metathesis and phosphorylation reactions of disulfide compounds is of widespread interests due to their important synthetic utility in polymer, biological, medicinal and agricultural chemistry. Herein, we demonstrate the use of N-heterocyclic carbenes (NHCs) as versatile organocatalysts to promote these challenging reactions under mild conditions. This metal-free oxidant-free protocol is operationally simple with very short reaction times. The interplay between the nucleophilicity and basicity of NHCs in these reactions were also elucidated by NMR studies and high-level ab initio calculations...
February 20, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28215139/bridgehead-nitrogen-thiazolo-3-2-a-pyrimidine-a-privileged-structural-framework-in-drug-discovery
#17
Amit K Keshari, Ashok K Singh, Sudipta Saha
Thiazolopyrimidine derivatives containing bridgehead nitrogen atom are now-a-days attracting the attention of many medicinal chemists throughout the world to explore this framework for its potential. This biologically important scaffold is formed by the fusion of two aromatic rings, thiazole and pyrimidine, in such a way that one carbon atom at the ring junction is replaced by a nitrogen atom and is, therefore, being common for both the heterocyclic rings. One of the most common example of this type of fusion is thiazolo[3,2-a]pyrimidine which is being used perpetually with tremendous success in various field of therapeutic applications...
February 16, 2017: Mini Reviews in Medicinal Chemistry
https://www.readbyqxmd.com/read/28203667/quantifying-and-understanding-the-steric-properties-of-n-heterocyclic-carbenes
#18
Adrián Gómez-Suárez, David J Nelson, Steven P Nolan
This Feature Article presents and discusses the use of different methods to quantify and explore the steric impact of N-heterocyclic carbene (NHC) ligands. These include (a) the percent buried volume (%Vbur), which provides a convenient single number to measure steric impact and (b) steric maps, which provide a graphical representation of the steric profile of a ligand using colour-coded contour maps. A critical discussion of the scope and limitations of these tools is presented, along with some examples of their use in organometallic chemistry and catalysis...
February 16, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28198438/heterogeneous-nucleation-of-trichloroethylene-ozonation-products-in-the-formation-of-new-fine-particles
#19
Ning Wang, Xiaomin Sun, Jianmin Chen, Xiang Li
Free radicals in atmosphere have played an important role in the atmospheric chemistry. The chloro-Criegee free radicals are produced easily in the decomposition of primary ozonide (POZ) of the trichloroethylene, and can react with O2, NO, NO2, SO2 and H2O subsequently. Then the inorganic salts, polar organic nitrogen and organic sulfur compounds, oxygen-containing heterocyclic intermediates and polyhydroxy compounds can be obtained. The heterogeneous nucleation of oxidation intermediates in the formation of fine particles is investigated using molecular dynamics simulation...
February 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28176260/green-synthesis-spectrofluorometric-characterization-and-antibacterial-activity-of-heterocyclic-compound-from-chalcone-on-the-basis-of-in-vitro-and-quantum-chemistry-calculation
#20
Salman A Khan
2-amino-4-(4-bromophenyl)-8-methoxy-5,6-dihydrobenzo[h]quinoline-3-carbonitrile (ABDC) was synthesized by the reaction of (2E)-2-(4 bromobenzylidene) - 6 -methoxy-3,4-dihydronaphthalen-1(2H)-one (Chalcone) with malononitrile and ammonium acetate under microwave irradiation. Chalcone was synthesised by the reaction 4-bromobenzaldehyd, 6-methoxy-1,2,3,4-tetrahydro-naphthalin-1-one under the same condition. Structure of ABDC was conformed by (1)H and (13)C NMR, FT-IR, EI-MS spectral studies and elemental analysis...
February 8, 2017: Journal of Fluorescence
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