Synthesis and characterization of new π‐conjugated polymers containing 1,8‐naphthyridine in the main chain: Role of the 1,8‐naphthyridine unit in π‐conjugated polymers

Alternating π‐conjugated copolymers of 1,8‐naphthyridine‐2,6‐diyl ( 1,8‐Nap ) with 9,9‐dioctylfluorene‐2,7‐diyl ( P(Flu‐Ph‐1,8‐Nap) ) and 2,5‐didodecyloxy‐1,4‐phenylene ( P(ROPh‐Ph‐1,8‐Nap) ) have been synthesized by Pd‐catalyzed organometallic polycondensation. The copolymers showed UV‐vis absorption peaks at around 390 nm in o‐dichlorobenzene. The polymers were photoluminescent both in o‐dichlorobenzene and in the solid state. In o‐dichlorobenzene, the emission peaks of P(Flu‐Ph‐1,8‐Nap) and P(ROPh‐Ph‐1.,8‐Nap) appeared at λ_EM = 440 and 471 nm, with quantum yields of 87% and 66%, respectively. Electrochemical data revealed that 1,8‐Nap behaved as a typical electron‐accepting unit. When P(Flu‐Ph‐1,8‐Nap) was treated with 10‐camphorsulfonic acid, the emission peak shifted to λ_EM = 598 nm. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Improved Synthesis of 2,2‐Arylmethylene Bis(3‐hydroxy‐5,5‐dimethyl‐2‐cyclohexene‐1‐one) and 1,8‐Dioxo‐octahydroxanthene Derivatives Catalyzed by Electrogenerated Base and Sulfuric Acid

An efficient method has been developed for the synthesis of 1,8‐dioxo‐octahydroxanthene derivatives in two‐step. In the first step, the electrogenerated base (EGB) catalyzed multicomponent transformation of dimedone and aromatic aldehydes in an undivided cell in the presence of sodium bromide as an electrolyte into 2,2′‐arylmethylene bis(3‐hydroxy‐5,5‐dimethyl‐2‐cyclohexene‐1‐one) at room temperature. In the second step, H₂SO₄ was employed as a dehydrating reagent for the cyclization process to give symmetrical heterocycles 1,8‐dioxo‐octahydroxanthene derivatives. Short reaction time, convenient work up, and using of inexpensive reagents, simple equipment, novel and eco‐friendly procedure make this strategy more useful for the preparation of xanthene derivatives.     

Synthesis and Characterization of Novel Monoazo N‐Ester‐1,8‐Naphthalimide Disperse Dyestuffs

Five novel monoazo disperse dyestuffs based on N‐ester‐1,8‐naphthalimide were synthesized. Acenaphthene was nitrated, then oxidized to 4‐nitro‐1,8‐naphthalic anhydride. 4‐Nitro‐1,8‐naphthalic anhydride was reacted with methyl and ethyl glycinate in alcoholic media, followed with reduction. 4‐Amino‐N‐methyl and ethyl glycinate‐1,8‐naphthalimide were obtained. These products were diazotized and coupled with appropriate aromatic amines to give bluish‐red or violet dyestuffs. All intermediates and dyestuffs were purified and characterized by ¹H‐NMR, FTIR, DSC, UV‐VIS and Elemental Analysis. Dispersion of dyestuffs was prepared in water and applied to polyester fabrics. The dyed fabrics showed that four of the synthesized dyestuffs were suitable for coloring polyester fibers, producing deep bluish red with very good build up properties.     

CuO‐CeO2 Nanocomposite: A Highly Efficient Recyclable Catalyst for the Green Synthesis of 1,8‐Dioxooctahydroxanthenes in Water

CuO‐CeO₂ nanocomposite is reported as a highly efficient and recyclable catalyst for the green synthesis of 1,8‐dioxooctahydroxanthenes in water. This catalyst can be recovered by simple filtration and recycled up to 8 consecutive runs without any losing of its efficiency.     

Catalytic application of sulfonic acid‐functionalized titana‐coated magnetic nanoparticles for the preparation of 1,8‐dioxodecahydroacridines and 2,4,6‐triarylpyridines via anomeric‐based oxidation

We have developed green, efficient and powerful protocols for the preparation of 2,4,6‐triarylpyridines and 1,8‐dioxodecahydroacridines in the presence of Fe₃O₄@TiO₂@O₂PO₂(CH₂)₂NHSO₃H as a sulfonic acid‐functionalized titana‐coated magnetic nanoparticle catalyst under mild and solvent‐free reaction conditions. These protocols furnished the desired products in short reaction times with good to high yields (20–40 min and 80–86% in the case of 2,4,6‐triarylpyridines; 15–90 min and 80–93% in the case of 1,8‐dioxodecahydroacridines). The final step of the mechanistic route in the synthesis of 2,4,6‐triarylpyridines proceeds via an anomeric‐based oxidation. Also, the nanomagnetic core–shell catalyst can be recycled and reused in both cases of the scrutinized one‐pot multicomponent reactions with high turnover number and turnover frequency.     

New polynuclear carbonyl ruthenium (II) complexes derived from 1,8‐naphthyridine

This work shows the synthesis and characterization of new carbonyl complexes derived of 1,8‐naphthyridine. Covalently bonded complex can be successfully employed in building of supramolecular structures. Copyright © 2005 John Wiley & Sons, Ltd.     

1,8‐Diazabicyclo[5.4.0]undec‐7‐ene: A Remarkable Base in the Debromination of 4‐ or 5‐Substituted N‐Benzyl α‐Bromo‐α‐p‐Toluenesulfonylglutarimide

Debromination of N‐benzyl 4‐ or 5‐substituted α‐bromo‐α‐p‐toluenesulfonylglutarimides is achieved with 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) to give the N‐benzyl 4‐ or 5‐substituted α‐p‐toluenesulfonylglutarimides. The DBU/THF system is applied to a new methodology for the synthesis of bicyclic glutarimide skeleton in moderate yields.     

Synthesis of 2‐Aryl‐2,3‐dihydro‐1,8‐naphthyridin‐4(1H)‐ones by Deprotective Cyclization of N‐{3‐[(2E)‐3‐Arylprop‐2‐enoyl]pyridin‐2‐yl}‐2,2‐dimethylpropanamides in Water

A new and convenient method for the preparation of 2‐aryl‐2,3‐dihydro‐1,8‐naphthyridin‐4(1H)‐ones 4 has been developed. Thus, N‐{3‐[(2E)‐3‐arylprop‐2‐enoyl]pyridin‐2‐yl}‐2,2‐dimethylpropanamides 3 are synthesized from commercially available pyridin‐2‐amine using an easily performed three‐step sequence and are subjected to cyclization with deprotection under acidic conditions in H₂O to give the desired products. Similarly, 2‐aryl‐2,3‐dihydro‐1,7‐naphthyridin‐4(1H)‐ones 8 and 2‐aryl‐2,3‐dihydro‐1,6‐naphthyridin‐4(1H)‐ones 12 can be prepared from pyridin‐3‐amine and pyridin‐4‐amine, respectively.     

N‐(2‐Bromoethyl)‐4‐piperidino‐1,8‐naphthalimide and N‐(3‐bromopropyl)‐4‐piperidino‐1,8‐naphthalimide

N‐(2‐Bromoethyl)‐4‐piperidino‐1,8‐naphthalimide, C₁₉H₁₉BrN₂O₂, (I), and N‐(3‐bromopropyl)‐4‐piperidino‐1,8‐naphthalimide, C₂₀H₂₁BrN₂O₂, (II), are an homologous pair of 1,8‐naphthalimide derivatives. The naphthalimide units are planar and each piperidine substituent adopts a chair conformation. This study emphasizes the importance of π‐stacking interactions, often augmented by other contacts, in determining the crystal structures of 1,8‐naphthalimide derivatives.     

Concise Synthesis and Two‐Photon‐Excited Deep‐Blue Emission of 1,8‐Diazapyrenes

Efficient violet–blue‐emitting molecules are especially useful for applications in full‐color displays, solid‐state lighting, as well as in two‐photon absorption (TPA) excited frequency‐upconverted violet–blue lasing. However, the reported violet–blue‐emitting molecules generally possess small TPA cross sections. In this work, new 1,8‐diazapyrenes derivatives 3 with blue two‐photon‐excited fluorescence emission were concisely synthesized by the coupling reaction of readily available 1,4‐naphthoquinone O,O‐diacetyl dioxime ( 1 ) with internal alkynes 2 under the [{RhCl₂Cp*}₂]–Cu(OAc)₂ (Cp*=pentamethylcyclopentadienyl ligand) bimetallic catalytic system. Elongation of the π‐conjugated length of 1,8‐diazapyrenes 3 led to the increase of TPA cross sections without the expense of a redshift of the emission wavelength, probably due to the rigid planar structure of chromophores. It is especially noteworthy that 2,3,6,7‐tetra(4‐bromophenyl)‐1,8‐diazapyrene ( 3c ) has a larger TPA cross section than those of other molecules reported so far. These experimental results are explained in terms of the effects of extension of the π‐conjugated system, intramolecular charge transfer, and reduced detuning energy.     

从Baylis-Hillman加成物合成1，2，3，4-四氢苯并萘啶-2-酮衍生物

本文介绍了（2）通过还原、两次环化的一锅串联反应制备了一系列1,2,3,4-四氢苯并萘啶-2-酮衍生物,反应条件温和,环境友好,产品易于分离,反应收率中等。起始原料可由Baylis－Hillman加成物通过Johnson-Claisen重排制备。     

A New Fluorescent Chemosensor for Cu2+ Based on 1,2,3,4,5,6,7,8,9,10‐Decahydroacridine‐1,8‐dione Fluorophore

A new chemosensor for Cu²⁺ was synthesized based on 1,2,3,4,5,6,7,8,9,10‐decahydroacridine‐1,8‐dione dyes, which exhibited an obvious fluorescent selectivity to the sensing of Cu²⁺ ions over other cations, such as Na⁺, K⁺, Ca²⁺, Cd²⁺, Co²⁺, Hg²⁺, Mg²⁺, Mn²⁺, Ni²⁺, Zn²⁺, Ag⁺ and Pb²⁺. Moreover, it presented a fluorescent switch function when EDTA was added to the compound‐Cu²⁺ complex in examined systems.     

Hydrogen‐Transfer‐Mediated α‐Functionalization of 1,8‐Naphthyridines by a Strategy Overcoming the Over‐Hydrogenation Barrier

A general catalytic hydrogen transfer‐mediated α‐functionalization of 1,8‐naphthyridines is reported for the first time that benefits from a hydrogen transfer‐mediated activation mode for non‐activated pyridyl cores. The pyridyl α‐site selectively couples with the C8‐site of various tetrahydroquinolines (THQs) to afford novel α‐functionalized tetrahydro 1,8‐naphthyridines, a class of synthetically useful building blocks and potential candidates for the discovery of therapeutic and bio‐active products. The utilization of THQs as inactive hydrogen donors (HDs) appears to be a key strategy to overcome the over‐hydrogenation barrier and address the chemoselectivity issue. The developed chemistry features operational simplicity, readily available catalyst and good functional group tolerance, and offers a significant basis for further development of new protocols to directly transform or functionalize inert N‐heterocycles.     

Determination of Selenium with a Poly(1,8‐diamino‐naphthalene)‐Modified Electrode

The performance of a poly(1,8‐diaminonaphthalene)‐modified electrode for the determination of the Se(IV) ion in an aqueous medium was investigated with anodic stripping voltammetry without the pretreating of the sample. The experimental parameters for the analysis of Se(IV) were optimized and the characteristics of this polymer‐modified electrode were investigated by using cyclic voltammetry. The Se(IV) ions were chemically deposited onto the surface of the pDAN‐Au electrode in an acidic medium. The detection limit employing the anodic stripping differential pulse voltammetry was 9.0×10^?9 M for Se(IV) with 4.4 % of RSD. Satisfactory result for the determination of Se(IV) was acquired employing a certified standard urine reference material, SRM's 2670 (trace element in urine) with 4.1 ppb of SD.     

A New Fluorescent Chemosensor for Metal Ions Based upon 1,8‐Naphthalimide and 8‐Hydroxyquinoline

A new fluorescent chemosensor based upon 1,8‐naphthalimide and 8‐hydroxyquinoline was synthesized, and its fluorescent properties in the presence of different metal cations (Hg²⁺, Ag⁺, Zn²⁺, Fe²⁺, Cd²⁺, Pb²⁺, Ca²⁺, Cu²⁺, Mg²⁺, and Ba²⁺) were investigated. It displayed fluorescence quenching with some heavy and transition metal (HTM) ions, and the quenching strongly depended on the nature of HTM ions.     

Poly[μ‐aqua‐μ4‐naphthalene‐1,8‐dicarboxylato‐zinc(II)]

In the title complex, [Zn(C₁₂H₆O₄)(H₂O)]_n, a Zn^II polymer based on naphthalene‐1,8‐dicarboxylate (1,8‐nap), the Zn^II atoms adopt an elongated octahedral coordination geometry. A zigzag chain is formed by μ₂‐aqua ligands and μ₂‐carboxylate groups of the 1,8‐nap ligands. Adjacent parallel chains are further linked by 1,8‐nap ligands, forming a twisted two‐dimensional layer structure along the (100) plane.     

Novel CuFe2O4@SiO2‐OP2O5H magnetic nanoparticles: Preparation,characterization and first catalytic application to the synthesis of 1,8‐dioxo‐octahydroxanthenes

New functionalized magnetic core–shell nanoparticles, CuFe₂O₄@SiO₂‐OP₂O₅H, were prepared by grafting of phosphorus pentoxide on CuFe₂O₄@SiO₂ nanoparticles and characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy‐dispersive X‐ray analysis, inductively coupled plasma optical emission spectrometry and vibrating sample magnetometry. The catalytic activity of CuFe₂O₄@SiO₂‐OP₂O₅H as a novel catalyst was evaluated in the synthesis of 1,8‐dioxo‐octahydroxanthenes under solvent‐free conditions. The results showed that the catalyst has high activity and the desired products are obtained in high yields within short reaction times. The catalyst is readily recovered using magnetic decantation and can be used at least four times without noticeable deterioration in catalytic activity.     

New green fluorescent polyvinylcarbazole copolymer with 1,8‐naphthalimide side chains as chemosensor for iron cations

The synthesis and basic photophysical characteristics of a novel green fluorescent polyvinylcarbazole polymer containing 4‐N,N‐dimethylaminoethyleneamino‐1,8‐naphthalimide side chains has been described. The ability to sense metal cations has been monitored by fluorescence emission spectroscopy. It is shown that the fluorescent intensity is very sensitive to the Fe²⁺ cations and the copolymer can be used as an homogeneous and heterogeneous fluorescent sensor for Fe²⁺ cations. Copyright © 2004 John Wiley & Sons, Ltd.     

Synthesis and characterization of new complexes of the type [Ru(CO)2Cl2 (2‐phenyl‐1,8‐naphthyridine‐kN) (2‐phenyl‐1,8‐naphthyridine‐kN′)]. Preliminary applications in homogeneous catalysis

Novel ruthenium (II) complexes were prepared containing 2‐phenyl‐1,8‐naphthyridine derivatives. The coordination modes of these ligands were modified by addition of coordinating solvents such as water into the ethanolic reaction media. Under these conditions 1,8‐naphthyridine (napy) moieties act as monodentade ligands forming unusual [Ru(CO)₂Cl₂(η¹‐2‐phenyl‐1,8‐naphthyridine‐ kN )(η¹‐2‐phenyl‐1,8‐naphthyridine‐kN′)] complexes. The reaction was reproducible when different 2‐phenyl‐1,8‐naphthyridine derivatives were used. On the other hand, when dry ethanol was used as the solvent we obtained complexes with napy moieties acting as a chelating ligand. The structures proposed for these complexes were supported by NMR spectra, and the presence of two ligands in the [Ru(CO)₂Cl₂(η¹‐2‐phenyl‐1,8‐naphthyridine‐ kN )(η¹‐2‐phenyl‐1,8‐naphthyridine‐kN′)] type complexes was confirmed using elemental analysis. All complexes were tested as catalysts in the hydroformylation of styrene showing moderate activity in N,N′‐dimethylformamide. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis of 10‐amino‐9‐aryl‐2,3,4,5,6,7,9,10‐octahydroacridine‐1,8‐dione derivatives

A series of novel 10‐amino‐9‐aryl‐2,3,4,5,6,7,9,10‐octahydroacridine‐1,8‐dione derivatives 4 were synthesized by hydrazine or phenylhydrazine and 9‐aryl‐1,8‐dioxo‐2,3,4,5,6,7,9‐heptahydroxanthene derivatives 3 , which were prepared by 5‐substituted‐1,3‐cyclohexanedione 1 and aromatic aldehydes 2 in the presence of concentrated H₂SO₄ as a catalyst in water. The structures of all compounds were characterized by IR, MS, ¹H‐NMR, and elemental analysis, and the title compounds possess good fluorescence properties. J. Heterocyclic Chem., (2012).