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Heterocyclic chemistry

Lisa Suntrup, Sinja Klenk, Johannes Klein, Sebastian Sobottka, Biprajit Sarkar
Bidentate ligands containing at least one triazole or triazolylidene (mesoionic carbene, MIC) unit are extremely popular in contemporary chemistry. One reason for their popularity is the similarities as well as differences in the donor/acceptor properties that these ligands display in comparison to their pyridine or other N-heterocyclic carbene counterparts. We present here seven rhenium(I) carbonyl complexes where the bidentate ligands contain combinations of pyridine/triazole/triazolylidene. These are the first examples of rhenium(I) complexes with bidentate 1,2,3-triazol-5-ylidene-containing ligands...
April 21, 2017: Inorganic Chemistry
Melanie W Lui, Olena Shynkaruk, Meagan S Oakley, Regina Sinelnikov, Robert McDonald, Michael J Ferguson, Al Meldrum, Mariusz Klobukowski, Eric Rivard
By investigating the coordination chemistry of a neutral N-heterocyclic olefin phosphine ligand, a new digold(i) chloride complex was discovered, demonstrating that mixed element (P/C) donor sites can be accessed at the same time. However attempts to extend this strategy for the preparation of heterobimetallic complexes featuring copper(i) and gold(i) centers with this mixed donor ligand were unsuccessful. The related monometallic copper(i) and gold(i) iodide complexes were discovered to be emissive in the solid state...
April 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Navriti Chadha, Om Silakari
Indoles constitute extensively explored heterocyclic ring systems with wide range of applications in pathophysiological conditions that is, cancer, microbial and viral infections, inflammation, depression, migraine, emesis, hypertension, etc. Presence of indole nucleus in amino acid tryptophan makes it prominent in phytoconstituents such as perfumes, neurotransmitters, auxins (plant hormones), indole alkaloids etc. The interesting molecular architecture of indole makes them suitable candidates for the drug development...
April 5, 2017: European Journal of Medicinal Chemistry
Lukas Omann, C David F Königs, Hendrik F T Klare, Martin Oestreich
Cooperative catalysis has attracted tremendous attention in recent years, emerging as a key strategy for the development of novel atom-economic and environmentally more benign catalytic processes. In particular, Noyori-type complexes with metal-nitrogen bonds have been extensively studied and evolved as privileged catalysts in hydrogenation chemistry. In contrast, catalysts containing metal-sulfur bonds as the reactive site are out of the ordinary, despite their abundance in living systems, where they are assumed to play a key role in biologically relevant processes...
April 13, 2017: Accounts of Chemical Research
Xi Mao, Tao Tong, Senbao Fan, Liting Fang, Jingyi Wu, Xiaoxia Wang, Honglan Kang, Xin Lv
A novel and expedient one-pot synthesis of thiazino[2,3,4-hi]indole derivatives from o-haloaryl enamines and o-bromothiophenols has been developed. The tandem oxidative coupling/heteroannulation reactions exhibit high selectivity and good efficiency. The polycyclic heterocyclic products obtained might be useful in medicinal chemistry and materials science.
April 12, 2017: Chemical Communications: Chem Comm
Wan Jung Kim, Keith Korthals, Suhua Li, Christine Le, Jaroslaw Kalisiak, K Barry Sharpless, Valery V Fokin, Yukiko Miyamoto, Lars Eckmann
Giardia lamblia is an important and ubiquitous cause of diarrheal disease. The primary agents in the treatment of giardiasis are nitroheterocyclic drugs, particularly the imidazoles metronidazole and tinidazole, and the thiazole, nitazoxanide. Although these drugs are generally effective, treatment failures occur in up to 20% of cases and resistance has been demonstrated in vivo and in vitro. Prior work had suggested that side chain modifications of the imidazole core can lead to effective new 5-nitroimidazole drugs that can combat nitro drug resistance, but the full potential of nitroheterocycles other than imidazole to yield effective new antigiardial agents has not been explored...
April 10, 2017: Antimicrobial Agents and Chemotherapy
Jitendra K Bera, Kuldeep Singh, Abir Sarbajna, Indranil Dutta, Pragati Pandey
A Ni(II) complex 1 containing pyridyl- and hydroxy-functionalized N-heterocyclic carbenes (NHC) is synthesized and its catalytic utility for selective nitrile hydration to amide under base-free condition is evaluated. The title compound exploits hemilabile pyridyl unit to interact with a catalytically relevant water molecule via hydrogen-bonding and promote nucleophilic water attack to the nitrile. A wide variety of nitriles are hydrated to the corresponding amides including pharmaceutical drugs Rufinamide, Rifater and Piracetam...
April 7, 2017: Chemistry: a European Journal
Sambasivarao Kotha, Chandravathi Chakkapalli
Indole and its derivatives captured the attention of organic chemists due to their applications in medicinal chemistry. The examples covered here are intricate polycyclic indole derivatives and these include: azapolyquinanes, cyclophanes, spirocycles and other heterocycles. We found that deep eutectic mixture such as L-(+)-tartaric acid (TA) and dimethyl urea (DMU) is useful to prepare complex unnatural indole derivatives. These conditions from time to time produced indole derivatives which are not possible by conventional methods...
April 5, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
Emanuel Hernández-Núñez, Hugo Tlahuext, Rosa Moo-Puc, Diego Moreno, María Ortencia González-Díaz, Gabriel Navarrete Vázquez
Parasitic diseases are a public health problem affecting millions of people worldwide. One of the scaffolds used in several drugs for the treatment of parasitic diseases is the benzimidazole moiety, a heterocyclic aromatic compound. This compound is a crucial pharmacophore group and is considered a privileged structure in medicinal chemistry. In this study, the benzimidazole core served as a model for the synthesis of a series of 2-(2-amino-5(6)-nitro-1H-benzimidazol-1-yl)-N-arylacetamides 1-8 as benznidazole analogues...
April 4, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Siddappa A Patil, Shivaputra A Patil, Renukadevi Patil
Macrocyclic chemistry is one of the emerging research areas in the chemical science. Macrocyclic compounds continue to attract significant attention due to their numerous possible applications particularly in the areas like biology, catalysis and industry. This review article summarizes the developments and advances in synthesis and medicinal applications of macrocyclic compounds derived from (benz)imidazole- and indole-based heterocycles. Important medicinal applications of (benz)imidazole- and indole-based macrocycles include antimicrobial and anticancer activities...
April 2017: Chemical Biology & Drug Design
Oleg I Artyushin, Elena V Sharova, Natalya M Vinogradova, Galina K Genkina, Aleksandra A Moiseeva, Zinaida S Klemenkova, Iana R Orshanskaya, Anna A Shtro, Renata A Kadyrova, Vladimir V Zarubaev, Olga I Yarovaya, Nariman F Salakhutdinov, Valery K Brel
A series of seventeen tetrazole derivatives of 1,7,7-trimethyl-[2.2.1]bicycloheptane were synthesized using click chemistry methodology and characterized by spectral data. Studies of cytotoxicity and in vitro antiviral activity against influenza virus A/Puerto Rico/8/34 (H1N1) in MDCK cells of the compounds obtained were performed. The structure-activity relationship analysis suggests that to possess virus-inhibiting activity, the compounds of this group should bear oxygen atom with a short linker (C2-C4), either as a hydroxyl group (18, 19, 29), keto-group (21) or as a part of a heterocycle (24)...
March 22, 2017: Bioorganic & Medicinal Chemistry Letters
Katarzyna N Lee, Zhen Lei, Ming-Yu Ngai
Umpolung (polarity reversal) strategies of aldehydes and imines have dramatically expanded the scope of carbonyl and iminyl chemistry by facilitating reactions with non-nucleophilic reagents. Herein, we report the first visible light photoredox-catalyzed β-selective reductive coupling of alkenylpyridines with carbonyl or iminyl derivatives with the aid of a Lewis acid co-catalyst. Our process tolerates complex molecular scaffolds (e.g., sugar, natural product, and peptide derivatives) and is applicable to the preparation of compounds containing a broad range of heterocyclic moieties...
March 30, 2017: Journal of the American Chemical Society
Saurabh S Chitnis, Rebecca A Musgrave, Hazel A Sparkes, Natalie E Pridmore, Vincent T Annibale, Ian Manners
Heterolytic cleavage of homoatomic bonds is a challenge, as it requires separation of opposite charges. Even highly strained homoatomic rings (e.g., cyclopropane and cyclobutane) are kinetically stable and do not react with nucleophiles or electrophiles. In contrast, cycloalkanes bearing electron-donating/withdrawing substituents on adjacent carbons have polarized C-C bonds and undergo numerous heterolytic ring-opening and expansion reactions. Here we show that upon electrophile activation phosphorus homocycles exhibit analogous reactivity, which is modulated by the amount of ring strain and extent of bond polarization...
March 27, 2017: Inorganic Chemistry
Kirsty Adams, Anthony K Ball, James Birkett, Lee Brown, Ben Chappell, Duncan M Gill, P K Tony Lo, Nathan J Patmore, Craig R Rice, James Ryan, Piotr Raubo, Joseph B Sweeney
Heterocyclic architectures offer powerful creative possibilities to a range of chemistry end-users. This is particularly true of heterocycles containing a high proportion of sp(3)-carbon atoms, which confer precise spatial definition upon chemical probes, drug substances, chiral monomers and the like. Nonetheless, simple catalytic routes to new heterocyclic cores are infrequently reported, and methods making use of biomass-accessible starting materials are also rare. Here, we demonstrate a new method allowing rapid entry to spirocyclic bis-heterocycles, in which inexpensive iron(III) catalysts mediate a highly stereoselective C-C bond-forming cyclization cascade reaction using (2-halo)aryl ethers and amines constructed using feedstock chemicals readily available from plant sources...
April 2017: Nature Chemistry
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
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
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
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...
April 18, 2017: Chemical Society Reviews
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
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
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