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Heterocyclic chemistry

Chunfang Gan, Liang Liu, Jianguo Cui, Zhiping Liu, Haixin Shi, Qifu Lin, Haibing Sheng, Chunhui Yang, Yanmin Huang
BACKGROUND: The modification of steroidal structure is commonly used to change the biological activity of steroids in medicinal chemistry. Some steroids containing heterocycles exhibit distinct cytotoxicity against various cancer cell lines and have been gotten wide attention over the years by medicinal chemists for drug discovery. METHODS: Using pregnenolone and stigmasterol as starting materials, via different chemical reaction, two series of heterosteroids with side chain of 20- and 22-hydrazone aromatic cycles or heterocycles in their structures were synthesized and characterized by IR, NMR and HRMS...
December 5, 2016: Medicinal Chemistry
Moustafa Sherief Moustafa, Saleh Mohammed Al-Mousawi, Hesham R El-Seedi, Mohamed Hilmy Elnagdi
Progress in chemistry synthetic methodologies of cyclic enaminonitriles is reported. Due to this progress, it becomes possible to reactivate these molecules toward electrophiles, nucleophiles and as electron rich dienes in 2+3 dipolar additions and in 4+2 cycloadditions reactions. Synthetizing the polyfunctionalized 4H-pyrans and their fused derivatives is a fascinating field with a multitude of biological implications such as antitumor, cardiotonic, hepatoprotective, antihypertensive, antibronchitis, as well antifungal activity...
November 29, 2016: Mini Reviews in Medicinal Chemistry
Sara Guariento, Anna Karawajczyk, James A Bull, Gessica Marchini, Martyna Bielska, Xenia Iwanowa, Olga Bruno, Paola Fossa, Fabrizio Giordanetto
Phosphodiesterase 4 (PDE4) inhibitors have attractive therapeutic potential in respiratory, inflammatory, metabolic and CNS disorders. The present work details the design, chemical exploration and biological profile of a novel PDE4 inhibitor chemotype. A diazepinone ring was identified as an under-represented heterocyclic system fulfilling a set of PDE4 structure-based design hypotheses. Rapid exploration of the structure activity relationships for the series was enabled by robust and scalable two/three-steps parallel chemistry protocols...
November 16, 2016: Bioorganic & Medicinal Chemistry Letters
Hanumappa Ananda, Kothanahally S Sharath Kumar, Mayilaadumveettil Nishana, Mahesh Hegde, Mrinal Srivastava, Raghava Byregowda, Bibha Choudhary, Sathees C Raghavan, Kanchugarakoppal S Rangappa
Pyrazole moiety represents an important category of heterocyclic compound in pharmaceutical and medicinal chemistry. The novel 1-aryl-3, 5-bis (het) aryl pyrazole derivatives were synthesized with complementary regioselectivity. The chemical structures were confirmed by IR, (1)H NMR, (13)C NMR, and mass spectral analysis. The chemical entities were screened in various cancer cell lines to assess their cell viability activity. Results showed that the compound 3-(1-(4-bromophenyl)-5-phenyl-1H-pyrazol-3-yl) pyridine (5d) possessed maximum cytotoxic effect against breast cancer and leukemic cells...
November 24, 2016: Molecular and Cellular Biochemistry
Wen Yang, Weimin Hu, Xiuqin Dong, Xin Li, Jianwei Sun
An N-heterocyclic carbene (NHC) catalyzed dihalomethylenation of enals is described. It is a rare example of merging NHC catalysis with single-electron chemistry, a challenging topic with limited previous success. The versatile carbon-centered trihalomethyl radicals have been demonstrated, for the first time, to be compatible with an NHC-bound intermediate, thus leading to efficient and regioselective intermolecular C-C bond formation. The mild process provides straightforward access to unsaturated δ,δ-dihalo esters...
November 22, 2016: Angewandte Chemie
Caixia Yuan, Xue-Feng Zhao, Yan-Bo Wu, Xiaotai Wang
Chemical bonding is at the heart of chemistry. Recent work on high bond orders between homonuclear transition metal atoms has led to ultrashort metal-metal (TM-TM) distances defined as dM-M <1.900 Å. The present work is a computational design and characterization of novel main group species containing ultrashort metal-metal distances (1.728-1.866 Å) between two beryllium atoms in different molecular environments, including a rhombic Be2 X2 (X=C, N) core, a vertical Be-Be axis in a 3D molecular star, and a horizontal Be-Be axis supported by N-heterocyclic carbene (NHC) ligands...
November 16, 2016: Angewandte Chemie
Zhi-Bin Zhang, Cai-Xia Xu, Xin Yin, Jian-Guo Zhang
The development of new environmentally friendly energetic compounds with reasonable detonation performance and safety is a long-term target in energetic materials research. A new energetic eco-friendly salt of hydrazine 5,5'-bitetrazole-1,1'-diolate (HA·BTO) is developed based on the reaction of 1H,1'H-5,5'-bitetrazole-1,1'-diolate (BTO) with hydrazine hydrochloride (HA·HCl), and fully characterized. The monocrystal of the title salt is obtained and the structure is determined by powder X-ray diffraction and single crystal X-ray diffraction...
November 18, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Kishor S Jain
No abstract text is available yet for this article.
2016: Current Topics in Medicinal Chemistry
Daniele Antermite, Leonardo Degennaro, Renzo Luisi
The almost unexplored four-membered heterocycles azetidines, represent a particularly interesting class of molecules, among the family of saturated nitrogen heterocycles. Although often challenging to synthesize, substituted azetidines strongly attract chemists because of their importance in catalysis, stereoselective synthesis and medicinal chemistry. This review aims to give a brief summary of modern developments in direct metal-based functionalization of the azetidine ring, focusing on the regio- and stereoselectivity of these reactions, as well as on some useful synthetic applications...
November 9, 2016: Organic & Biomolecular Chemistry
Rachel C Furnival, Rungroj Saruengkhanphasit, Heather E Holberry, Jonathan R Shewring, Hélène D S Guerrand, Harry Adams, Iain Coldham
Simple haloaldehydes, including enolisable aldehydes, were found to be suitable for the formation of cyclic products by cascade (domino) condensation, cyclisation, dipolar cycloaddition chemistry. This multi-component reaction approach to heterocyclic compounds was explored by using hydroxylamine, a selection of aldehydes, and a selection of activated dipolarophiles. Initial condensation gives intermediate oximes that undergo cyclisation with displacement of halide to give intermediate nitrones; these nitrones undergo in situ intermolecular dipolar cycloaddition reactions to give isoxazolidines...
November 7, 2016: Organic & Biomolecular Chemistry
Tamal Chatterjee, Vijayendra S Shetti, Ritambhara Sharma, Mangalampalli Ravikanth
The heteroatom-containing porphyrin analogues or core-modified porphyrins that resulted from the replacement of one or two pyrrole rings with other five-membered heterocycles such as furan, thiophene, selenophene, tellurophene, indene, phosphole, and silole are highly promising macrocycles and exhibit quite different physicochemical properties compared to regular azaporphyrins. The properties of heteroporphyrins depend on the nature and number of different heterocycle(s) present in place of pyrrole ring(s)...
November 4, 2016: Chemical Reviews
Haipeng Lu, Zhaohui Zhou, Oleg V Prezhdo, Richard L Brutchey
N-heterocyclic carbenes (NHCs) are becoming increasingly popular ligand frameworks for nanocrystal surfaces; however, as of yet, the nature of the NHC-nanocrystal interface remains unexplored across different material types. Here, we report a facile synthetic route to NHC-stabilized metal and metal chalcogenide nanocrystals. It was observed that NHC-Ag nanocrystals are colloidally stable, but much less so than the corresponding NHC-Ag2E analogs. Comprehensive NMR studies suggest a dynamic NHC-nanocrystal interface for both NHC-Ag and Ag2S; however, DFT calculations reveal a much stronger binding affinity of the NHC ligands to Ag2S compared to Ag nanocrystals, which explains the superior colloidal stability of the metal chalcogenides...
October 28, 2016: Journal of the American Chemical Society
Kapileswar Seth, Priyank Purohit, Asit K Chakraborti
The benzazole scaffolds are present in various therapeutic agents and have been recognized as the essential pharmacophore for diverse biological activities. These have generated interest and necessity to develop efficient synthetic methods of these privileged classes of compounds to generate new therapeutic leads for various diseases. The biological activities of the benzazoles and efforts towards their synthesis have been summarized in a few review articles. In view of these, the aim of this review is to provide an account of the developments that have taken place in the synthesis of biorelevant benzazoles under microwave irradiation as the application of microwave heating has long been recognized as a green chemistry tool for speedy generation of synthetic targets...
October 25, 2016: Current Medicinal Chemistry
Paul Mehlmann, Christian Mück-Lichtenfeld, Tristan T Y Tan, Fabian Dielmann
We report the synthesis and remarkable properties of the phosphine P(NIiPr)3 (NIiPr=1,3-diisopropyl-4,5-dimethylimidazolin-2-ylidenamino), a crystalline solid accessible through a short and scalable route. Evaluation of the electron-donor properties reveals a Tolman electronic parameter (TEP) value of 2029.7 cm(-1) for the new phosphine that is significantly lower than those of all known phosphines or even N-heterocyclic carbenes. Moreover, P(NIiPr)3 is more basic [pKBH(+) (MeCN)=38.8] than Verkade's proazaphosphatranes, thus being the strongest reported nonionic phosphorus(III) superbase...
October 25, 2016: Chemistry: a European Journal
Abdul Hameed, Mariya Al-Rashida, Maliha Uroos, Syed Ali, Khalid M Khan
Schiff bases are synthetically accessible and structurally diverse compounds, typically obtained by facile condensation between an aldehyde, or a ketone with primary amines. Schiff bases contain an azomethine (-C=N-) linkage that stitches together two or more biologically active aromatic/heterocyclic scaffolds to form various molecular hybrids with interesting biological properties. Schiff bases are versatile metal complexing agents and have been known to coordinate all metals to form stable metal complexes with vast therapeutic applications...
October 24, 2016: Expert Opinion on Therapeutic Patents
Bubun Banerjee
Heterocycles are the backbone of organic compounds. Specially, N- &O-containing heterocycles represent privileged structural subunits well distributed in naturally occurring compounds with immense biological activities. Multicomponent reactions (MCRs) are becoming valuable tool for synthesizing structurally diverse molecular entities. On the other hand, the last decade has seen a tremendous outburst in modifying chemical processes to make them sustainable for the betterment of our environment. The application of ultrasound in organic synthesis is fulfilling some of the goals of 'green and sustainable chemistry' as it has some advantages over the traditional thermal methods in terms of reaction rates, yields, purity of the products, product selectivity, etc...
March 2017: Ultrasonics Sonochemistry
Song-Lin Zhang, Ze-Long Yu
Divergent synthesis of indoles, oxindoles, isocoumarins and isoquinolinones is described in this report by using a general Pd-catalyzed tandem reaction of β-hydroxy carbonyl compounds with aryl halides bearing an ortho-nitro, -ester or -cyano substituent. A key retro-aldol/α-arylation reaction is involved that merges classic Pd cross-coupling chemistry with novel Pd-promoted retro-aldol C-C activation to produce α-arylated ketones or esters. Subsequent intramolecular condensation of the carbonyl with the ortho-synthon gives target heterocycles...
October 21, 2016: Organic & Biomolecular Chemistry
Sudipta Saha, Vinit Raj, Amit Rai
The chemistry of heterocyclic containing, 1,3,4-thiadiazole has been an interesting field of study from ancient years. Subsequently, 1,3,4-thiadiazole nucleus constitutes a significant class of compounds for new drug development. Recently, various 1,3,4-thiadiazole derivatives have been synthesized and evaluated their biological activities including antimicrobial, antituberculosis, antioxidant, anti-inflammatory, anticonvulsants, antidepressant and anxiolytic, antihypertensive, anticancer and antifungal activity...
October 13, 2016: Anti-cancer Agents in Medicinal Chemistry
Pierre Regenass, Stéphanie Riché, Florent Péron, Didier Rognan, Marcel Hibert, Nicolas Girard, Dominique Bonnet
A rapid and atom economical multicomponent synthesis of complex aza-diketopiperazines (aza-DKPs) driven by Rh(i)-catalyzed hydroformylation of alkenylsemicarbazides is described. Combined with catalytic amounts of acid and the presence of nucleophilic species, this unprecedented multicomponent reaction (MCR) enabled the formation of six bonds and a controlled stereocenter from simple substrates. The efficacy of the strategy was demonstrated with a series of various allyl-substituted semicarbazides and nucleophiles leading to the preparation of 3D-shaped bicyclic aza-DKPs...
September 21, 2016: Organic & Biomolecular Chemistry
Sonu Kumar, Rakesh K Saunthwal, Trapti Aggarwal, Siva K Reddy Kotla, Akhilesh K Verma
An efficient step-economical tandem approach for the direct synthesis of pyrido fused indole, quinoline, benzofuran and benzothiophene derivatives using a bimetallic Pd/Cu catalytic system has been described. The three component reaction of o-halo aldehydes, alkynes and tert-butylamine leads to the synthesis of biologically active polyheterocycles. The present strategy involves the dual role of tert-butylamine and copper(i) in Sonogashira coupling followed by electrophilic cyclization through imine formation...
September 26, 2016: Organic & Biomolecular Chemistry
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