PDF superior Pyridinium N 2´ pyridylaminide: radical cyclization for the synthesis of benzonaphthyridine derivatives

Pyridinium N 2´ pyridylaminide: radical cyclization for the synthesis of benzonaphthyridine derivatives

Pyridinium N 2´ pyridylaminide: radical cyclization for the synthesis of benzonaphthyridine derivatives

Platinum on charcoal (5%) (75 mg) was suspended in a stirred solution of the corresponding pyridinium salt 13 (0.31 mmol) in MeCN (3 mL) and cooled in an ice bath. Formic acid (96%, 1.5 mL) in MeCN (1.5 mL) and then tri- ethylamine (4.5 mL) in the same solvent (3 mL) were added dropwise. The resulting suspension was stirred at room tem- perature and filtered through Celite. The filtrate was evapo- rated and the residue dissolved in water, made basic with solid potassium carbonate, and extracted with EtOAc. The combined organic phases were dried over Na 2 SO 4 , filtered,
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Pyridinium N 2´ pyridylaminide: synthesis of 3 aryl 2 aminopyridines through an intramolecular radical process

Pyridinium N 2´ pyridylaminide: synthesis of 3 aryl 2 aminopyridines through an intramolecular radical process

interested in the chemistry of pyridinium N-2 0 -pyridylami- nide, 1a (Scheme 1), a stable heterocyclic betaine, that has a p-deficient pyridinium fragment attached to a p-excessive 2-iminopyridine moiety. This compound has proven to be a versatile scaffold in a wide range of transformations. Thus, for example, the preparation of 3-or 3,5-halogenated 2-alkyl aminopyridines from 1a can be carried out by an easy and selective halogenation at the iminopyridine moiety (for supply, for example 1b, Scheme 1), followed by regio- selective N-alkylation at the aminide nitrogen and final reduction of NN bond. 3
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Complementary regioselectivity in the synthesis of iminohydantoins: remarkable effect of amide substitution on the cyclization

Complementary regioselectivity in the synthesis of iminohydantoins: remarkable effect of amide substitution on the cyclization

We have studied the three centers-two component reaction (3C-2CR) of chloramines with isocyanoacetamides, where the amide moiety was expected to be chlorinated and then interact as an electrophile with the isocyanide divalent carbon, leading directly to interesting heterocyclic structures. In this way, we attempted the reaction between N-alkyl- and N-aryl isocyano- acetamides 15 (1) and chloramines (2) to synthesize aminoimid- azolidinones from a simple reaction under phase transfer conditions. Therefore, a small amount of TEBA (benzyltriethyl- ammonium chloride) was added to a stirred suspension of iso- cyanoacetamide 1a–i (1 equiv.) and dry chloramine (B, 2a, or T, 2b) (1 equiv.) in dry chloroform at room temperature for 4 days. Aqueous work-up, extraction with chloroform and recrys- tallization gave iminohydantoin derivatives 3–4 in fair yields (Table 1).
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Suzuki reaction on pyridinium N haloheteroarylaminides: regioselective synthesis of 3,5 disubstituted 2 aminopyrazines

Suzuki reaction on pyridinium N haloheteroarylaminides: regioselective synthesis of 3,5 disubstituted 2 aminopyrazines

Polysubstituted heterocycles belong to the most important class of organic compounds, they are widespread in nature and many of them show interesting biological activities. 1 Functionalization of halo- or metallated heteroaromatic com- pounds through metal-mediated cross-coupling reactions has become an important method for the preparation of different multiple carbon-substituted heterocycles 2 and, in recent years, selective Pd-mediated reactions have been developed to prepare highly functionalized heterocycles. 3 The Suzukie Miyaura cross-coupling reaction has proved to be a powerful and versatile method for the formation of Csp 2 eCsp 2 bonds. 4 The process has important advantages over the other palla- dium-catalyzed cross-coupling processes and these include functional group compatibility, low toxicity of reagents and intermediates, ready availability of boron derivatives, high thermal stability and good tolerance against oxygen and aque- ous solvents. Recently, efforts have been focused on the devel- opment of efficient and selective catalytic systems that either
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An easy preparation of pyridinium N heteroarylaminides

An easy preparation of pyridinium N heteroarylaminides

General method. Potassium carbonate (1.86 g, 13.5 mmol) was added to a solution of the N-aminopyridinium iodide 6 (1 g, 4.5 mmol) in acetonitrile (20 mL) and the reaction mixture was vigorously stirred for 45 min at room temperature to give a purple solution of compound 7. Over this solution, the corresponding a-chloroheterocycle 8 (4.7 mmol) in acetonitrile (5 mL) was added. The mixture was either stirred at room temperature or refluxed (see Table 1) until no starting material was detected by TLC. The inorganic salts were filtered through zelite, the filtrate was evaporated in vacuo and the product was purified by chromatography on silica gel using ethanol as eluent, crystallized from the suitable solvent and identified. The following compounds were prepared according the general method.
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SYNTHESIS OF GERANYLHYDROQUINONE DERIVATIVES WITH POTENCIAL CYTOTOXIC ACTIVITY

SYNTHESIS OF GERANYLHYDROQUINONE DERIVATIVES WITH POTENCIAL CYTOTOXIC ACTIVITY

Furthermore, natural geranylquinone 3 and geranylhydroquinone derivatives (4-5) were obtained by chemical transformations of the coupling compounds 1 and 2. Compounds 1 and 3 showed cytotoxic activity against prostate cancer cell line PC-3, as well as breast cancer cell lines MCF-7 and MDA-MB231. However the citotoxicity was lower than the positive control (dunnione). Moreover, these compoun- ds showed some selectivity for the cancer cells versus fibroblast cells. The increased citotoxicity induced in the cell lines by compounds 1 and 3 due to the presence of hydroquinone or quinone moiety in the structure of these compounds versus compounds 2, 4 and 5. SUPPLEMENTARY MATERIAL
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Optimization of the pharmacophore model for 5 HT7R antagonism, design and synthesis of new naphtholactam and naphthosultam derivatives

Optimization of the pharmacophore model for 5 HT7R antagonism, design and synthesis of new naphtholactam and naphthosultam derivatives

ascorbic acid, 0.01 mM pargyline, and 3 µM pindolol buffer (pH 7.4 at 25 °C)). Nonspecific binding was determined with 10 µM 5-HT. Competing drug, nonspecific, total, and radio- ligand bindings were defined in triplicate. Incubation was terminated by rapid vacuum filtration through Whatman GF/C filters, presoaked in 0.01% poly(ethylenimine), using a Brandel cell harvester. The filters were then washed with the assay buffer and were placed in vials to which were added 4 mL of a scintillation cocktail (Ecolite), and the radioactivity bound to the filters was measured by liquid scintillation spectrometry. The data were analyzed by an iterative curve-fitting procedure (program Prism Graph Pad), which provided IC 50 , K i , and r 2
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Estudio electroqumico de derivados de cis diferrocenileteno

Estudio electroqumico de derivados de cis diferrocenileteno

potentiostat/galvanostat EG&G PAR model 263 controlled by a PC software was used. A typical three-electrode array was employed for all electrochemical measurements: platinum disk as working electrode, platinum wire as counter-electrode, and a pseudo reference electrode of silver wire immersed in an butironitrile solution with 0.1 M tetra-N-butylammonium chloride (TBACl). All solutions were bubbled with nitrogen prior each measurement. All voltammograms were initiated from open circuit potential (E ocp ) and the scan potential was obtained in both positive and negative directions. All potentials were reported
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Design and synthesis of simplified sordaricin derivatives as inhibitors of fungal protein synthesis

Design and synthesis of simplified sordaricin derivatives as inhibitors of fungal protein synthesis

Keywords: antibiotics; enzyme inhibitors; fungi; molecular modeling~mechanics Sordadn la is an antifungal mould metabollte isolated from Sordaria araneosa, t Derivatives of sordarin la a[r]

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Synthesis and evaluation of the antifungal activity of 2-(substituted-amino)-4,5-dialkyl-thiophene-3- carbonitrile derivatives

Synthesis and evaluation of the antifungal activity of 2-(substituted-amino)-4,5-dialkyl-thiophene-3- carbonitrile derivatives

All compounds presented fungicidal activity at different doses, but a few compounds showed moderate or poor antifungal activity when compared with the standard drugs. The Cryp- tococcus[r]

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Synthesis and cytotoxic activity of geranylmethoxyhydroquinone derivatives

Synthesis and cytotoxic activity of geranylmethoxyhydroquinone derivatives

In summary, we have prepared the new synthetic geranyl-2,4- methoxyhydroquinone 1 and known geranyl-4,5-methoxyhydroquinone 2. These compounds were obtained unexpectedly by Electrophilic Aromatic Substitution (EAS) coupling reactions between geraniol with 2,4,5-trimethoxyphenol. Furthermore, the geranylmethoxyhydroquinone derivatives (3-6) were obtained of the chemical transformations of the compounds coupling 1 and 2. The compound 5 showed cytotoxic activity against cell line MCF-7 and MDA-MB-231 with IC 50 values of 84.2 and 86.2
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Chemical bath deposition route for the synthesis of ultra thin CuIn(S,Se)2 based solar cells

Chemical bath deposition route for the synthesis of ultra thin CuIn(S,Se)2 based solar cells

The research leading to these results has received funding from the People Program (Marie Curie Actions) of the European Union's Seventh Framework Program FP7/2007 – 2013/ under REA grant agreement No. 316488 (KESTCELLS) and No. 285897 (INDUCIS), by European Regional Development Funds (ERDF, FEDER Programa Competitivitat de Catalu- nya 2007 – 2013), and CONACyT project No. 178228 and Laboratory Re- search and Technological Development 2009 No. 124177. Authors from IREC and IN2UB belong to the M-2E (Electronic Materials for Energy) Consolidated Research Group and the XaRMAE Network of Excellence on Materials for Energy of the “ Generalitat de Catalunya ” . Y.S. thanks the PTA fellowship (PTA2012-7852-A), H.X. the “ China Scholarship Council ” fellowship (CSC No. 201206340113), V.I. the “ Juan de la Cierva ” fellowship (JCI-2011-10782) and E.S. the “ Ramon y Cajal ” fellowship (RYC-2011-09212).
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KNbO3 as Photocatalyst for Hydrogen Production

KNbO3 as Photocatalyst for Hydrogen Production

Various compounds photocatalytic such as niobates, tantalates and titanates, have been reported towards the production of hydrogen by the dissociation of the water molecule with reasonable activity [14, 15]. The main objective of this study is to evaluate the photocatalytic activity of commercial and synthesized potassium niobate (KN) samples from three different synthesis methods. The study took place through: (1) the synthesis of KN nanoparticles using three synthesis methodologies; (2) the characterization of the commercial and KN synthesized powders and the; (3) the evaluation of photocatalytic activities of all KN samples.
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Analytic and numerical tools for the study of quasi-periodic motions in hamiltonian systems.

Analytic and numerical tools for the study of quasi-periodic motions in hamiltonian systems.

Let us remark that due to the importance, both theoretical and applied, of invariant curves of maps or 2-dimensional tori of flows (for example, they play a fundamental role in the design of space missions [GJSM01a, GJSM01b] and also in the study of models in Celestial Mechan- ics [SM71], Molecular Dynamics [PCU08, TLBB01] or Plasma-Beam Physics [Mic95], just to mention a few), several approaches to deal with these objects have been developed in the liter- ature. For example, the methods in [CJ00, dlLHS, JO] have been applied efficiently in a wide set of contexts. However, they require to compute a representation —by means of a trigono- metric polynomial— of the curve which solves the invariance equation of the problem, so it is required to solve large systems of equations —as large as the used number of Fourier modes, say M . One possibility to face this difficulty is to solve these full linear systems, with a cost O (M 3 ) in time and O (M 2 ) in memory, by means of efficient parallel algorithms as is proposed
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Enantioselective Synthesis of Cyclopentadienes by Gold(I)  Catalyzed Cyclization of 1,3 Dien 5 ynes

Enantioselective Synthesis of Cyclopentadienes by Gold(I) Catalyzed Cyclization of 1,3 Dien 5 ynes

was oven-dried (120 °C), evacuated and purged with nitrogen. All common reagents and solvents were obtained from commercial suppliers (VWR, Alfa and Aldrich) and used without any further purification. Solvents were dried by standard methods. Hexane and ethyl acetate were purchased as extra pure grade reagents and used as received. Gold and silver catalysts were purchased from Aldrich or Strem. Chiral gold (I) complexes were prepared according to the methods described in the literature. [25a] For the preparation of starting dienynes see the Supporting Information. TLC was performed on aluminum-backed plates coated with silica gel 60 with F254 indicator; the chromatograms were visualized under ultraviolet light and/or by staining with a Ce/Mo reagent and subsequent heating. R f values are reported on silica gel. Flash column
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Synthesis and Anti-HIV Activity Evaluation of 2-(5-(Naphthalen-1-yl)-1,2,3-thiadiazol-4-ylthio)-N-acetamides Derivatives

Synthesis and Anti-HIV Activity Evaluation of 2-(5-(Naphthalen-1-yl)-1,2,3-thiadiazol-4-ylthio)-N-acetamides Derivatives

SUMMARY. The development of novel HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) offers the possibility of generating novel structures of increased potency. Based on the bioisosterism principle, two novel 2-(5-(naphthalen-1-yl)-1,2,3-thiadiazol-4-ylthio)-N-acetamides derivatives have been designed, synthe- sized and evaluated for their anti-HIV activities in MT-4 cells. The results indicate that these compounds show good activities against HIV-1. Especially, compound 9B (EC

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Synthesis and reactivity of N alkyl 2 oxoalkanesulfonamides

Synthesis and reactivity of N alkyl 2 oxoalkanesulfonamides

The solvent was removed under reduced pressure and the residue chromatographed on silica gel using hexanes/ethyl acetate.. Aeylation of lq..[r]

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Synthesis, characterization, determination of luminescent properties of tetracoordinate organoboron compounds derivatives from organic tridentate ligands, and their potential application in OLEDs

Synthesis, characterization, determination of luminescent properties of tetracoordinate organoboron compounds derivatives from organic tridentate ligands, and their potential application in OLEDs

On the other hand, considerable effort has been invested in the design and synthesis of new boron compounds, which has improved the chemical and optical properties in comparison to aluminum derivatives such as good solubility in organic solvents, high fluorescent quantum yields (Φ), air-stable, low cost, and easy deposition on substrate surfaces by means of direct thermal evaporation. 5 In this regard, much attention has been paid to transition metal complexes due to their interesting electroluminescent properties such as highly emission and good thermal stability. 6 However, heavy metals such as Ir, 7 Pt, 8 and Cu 9 are extremely moisture- and/or oxygen- sensitive.
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Pyridinium N (2´ azinyl)aminides: Regioselective synthesis of N (2 pyridyl) substituted polyamines

Pyridinium N (2´ azinyl)aminides: Regioselective synthesis of N (2 pyridyl) substituted polyamines

increases, longer time was necessary to obtain a similar conversion, and in compounds 9a– f about a 15% of starting aminide 2a was always detected. On the contrary, with short dialkylating agents, like in the synthesis of 12 (Scheme 3) from 1,2-diiodoethane or 1,3-diiodopropane, no bis-alkyl- ation was observed on 2a, probably due to electronic repulsion in the intermediate salt. With diiodoethane, 2a was recovered as hydroiodide, indicating a predominance of the elimination process, while compound 13 was obtained from 1,3-diiodopropane.
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Synthesis and cytotoxic activity of per acetylated and halogenated derivatives of nucleosides in breast cancer cells

Synthesis and cytotoxic activity of per acetylated and halogenated derivatives of nucleosides in breast cancer cells

The halogenation reaction with NCS and NBS allowed the selective substitution on the 5-position of uracil and cyto- sine ring of each nucleoside with quantitative conversions. As the esterification performed with acetic anhydride as reagent and solvent does not require heating or aggressive mediums (acidic or basic), it is an ideal reaction for high- ly acid labile substrates or thermo-labile, like nucleosides. This reaction is assisted with a nucleophilic catalyst, allow- ing the per-acylation of nucleosides, achieving the esters formation of all hydroxyl groups of ribose and arabino- furanosyl rings of uridine and cytarabine, respectively, and the amide formation on amine group of cytosine ring in the second nucleoside 4,21 .
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