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1.
Recently, acid–base bifunctional catalysts have been considered due to their abilities, such as the simultaneous activation of electrophilic and nucleophilic species and their high importance in organic syntheses. However, the synthesis of acid–base catalysts is problematic due to the neutralization of acidic and basic groups. This work reports a facial approach to solve this problem via the synthesis of a novel bifunctional polymer using inexpensive materials and easy methods. In this way, at the first step, heterogeneous poly (styrene sulfonic acid‐n‐vinylimidazole) containing pentaerythritol tetra‐(3‐mercaptopropionate) (PETMP) and trimethylolpropane trimethacrylate (TMPTMA) cross‐linkers were synthesized in the pores of a mesoporous silica structure using click reaction as a novel bifunctional acid–base catalyst. After that, Ni‐Pd nanoparticles supported on poly (styrenesulfonic acid‐n‐vinylimidazole)/KIT‐6 as a novel trifunctional heterogeneous acid–base‐metal catalyst was prepared. The prepared catalysts were characterized by various techniques like FT‐IR, TGA, ICP‐AES, DRS‐UV, TEM, FE‐SEM, EDS‐Mapping, and XRD. The synthesized catalysts were efficiently used as bifunctional/trifunctional catalysts for one‐pot, deacetalization‐Knoevenagel condensation and one‐pot, three‐step and a sequential reaction containing deacetalization‐Knoevenagel condensation‐reduction reaction. It is important to note that the synthesized catalyst showing high chemo‐selectivity for the reduction of nitro group, alkenyl double bond and ester group in the presence of nitrile. Moreover, it was found that the different nanoparticles including Ni, Pd, and alloyed Ni‐Pd showing different chemo‐selectivity and catalytic activity in the reaction.  相似文献   

2.
A high‐performance liquid chromatographic (HPLC) method for enantioseparation of bupropion was developed using two isothiocyanate‐based chiral derivatizing reagents, (S)‐1‐(1‐naphthyl) ethyl isothiocyanate, (S)‐NEIT, and (R)‐α‐methyl benzyl isothiocyanate, (R)‐MBIT. The diastereomers synthesized with (S)‐NEIT were enantioseparated by reversed‐phase HPLC using gradient elution with mobile phase containing water and acetonitrile, whereas diastereomers synthesized with (R)‐MBIT were enantioseparated using triethyl amine phosphate buffer and methanol. Derivatization conditions were optimized and the method was validated for accuracy, precision and limit of detection. The limit of detection was found to be 0.040–0.043 µg/mL for each of the diastereomers prepared with (S)‐NEIT. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

3.
The new thermal radical initiators (TRIs) with linear and cyclic type groups based on derivatives of O‐imino‐isourea have been designed and synthesized. The radical polymerization property of the synthesized TRI derivatives as a radical initiator in n‐butyl acrylate was monitored by differential scanning calorimetry analysis. TRI derivatives with linear type groups, such as 3‐PenDCC, 3‐HexDCC, and 4‐HepDCC, showed peak temperatures (Tpeak) of 80–84 °C, whereas those with cyclic type groups, such as C‐PenDCC, C‐HexDCC, and C‐HepDCC, exhibited a wide Tpeak distribution in the 74–87 °C range. The polymerization efficiency using new TRIs in n‐butyl acrylate was elaborately identified from the molecular weights and conversion obtained using gel permeation chromatography analysis and NMR spectroscopy. To consider their possible application to automotive clearcoats, the real‐time evolution of the rheological properties of clearcoat resins during the crosslinking process with newly synthesized TRI derivatives was measured, confirming the different crosslinking kinetics of TRI derivatives in real thermal curing process. The results were found to be well correlated with data from the radical polymerization experiments of TRIs. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3593–3600.  相似文献   

4.
Ferrocene‐based polymers are characterized by their electrochemical activity, good redox properties, thermal, photochemical stability, and liquid crystallinity, and thus they have various applications in different fields. A comprehensive investigation on the synthesis and properties of three novel main‐chain ferrocene‐based polyesters with azobenzene in the side chain (MFPAS) was carried out. The main‐chain ferrocene‐based polyester, poly(N‐phenyldiethanolamine 1,1′‐ferrocene dicarboxylate (PPFD), was synthesized via the solution polycondensation reaction of 1,1′‐ferrocenedicarbonyl chloride with phenyldiethanolamine (PDE). The novel MFPAS were synthesized via the post‐polymerization azo‐coupling reaction of PPFD with three different 4‐substituted anilines including 4‐nitroaniline, 4‐aminobenzoic acid, and 4‐aminobenzonitrile to produce 4‐nitrophenylazo‐functionalized‐PPFD (PPFD‐NT), 4‐carboxyphenylazo‐functionalized‐PPFD (PPFD‐CA), and 4‐cyanophenylazo‐functionalized‐PPFD (PPFD‐CN), respectively. All the synthesized polymers were characterized by 1H NMR spectroscopy, Fourier transform infrared spectroscopy, and UV–visible spectroscopy. In addition, powder X‐ray diffraction patterns were measured for the synthesized polymers. The photoisomerization of the MFPAS was studied. The thermal properties of the MFPAS were studied using thermogravimetric analysis and differential scanning calorimetry. PPFD‐CA and PPFD‐CN were found to be more thermally stable than PPFD‐NT. Finally, the liquid‐crystalline properties of PPFD and the MFPAS were examined using polarized optical microscope. It was found that all the polymers possessed nematic phases and exhibited textures with schlieren disclinations. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

5.
A highly efficient and reusable molybdenum‐based catalyst has been synthesized by covalent grafting of a bis(phenol) diamine ligand, namely 2‐(((2‐bromoethyl)(2‐((3,5‐di‐tert‐butyl‐2‐hydroxybenzyl)amino)ethyl)amino)methyl)‐4,6‐di‐tert‐butylphenol, onto functionalized ordered mesoporous silica (SBA‐15) followed by complexation with MoO2(acac)2. The resulting organic–inorganic hybrid material was found to be a highly effective catalyst for oxygenation of various sulfides to their corresponding sulfoxides or sulfones. The catalyst was characterized using transmission and scanning electron microscopies, X‐ray photoelectron, Fourier transform infrared and atomic absorption spectroscopies, Brunauer–Emmett–Teller surface area analysis and thermogravimetric analysis. Mild reaction conditions, high selectivity and easy recovery and reusability of the catalyst render the presented protocol very useful for addressing industrial needs and environmental concerns.  相似文献   

6.
Poly(2‐vinylpyridine) (P2VP) containing functionalized end groups was synthesized using nitroxyl‐mediated radical polymerization with a hydroxy‐functionalized stable free radical. It was shown that P2VP could be synthesized with variable molar masses and low polydispersities. The transformation of the hydroxy groups to an acrylic ester led to the formation of macromonomers. A free‐radical copolymerization of these macromonomers with N‐isopropylacrylamide gave a graft copolymer with a poly(N‐ispopropylacrylamide) backbone and P2VP side chains. Polymers containing different amounts of the monomers were synthesized. It was possible to vary both the amount of P2VP side chains at a constant chain length of the macromonomer and the chain length at a nearly constant chain number. The behavior of the multifunctional macromolecules at different temperatures and pH values was investigated using dynamic light scattering and DSC. The macromolecules were found to retain the specific properties of the homopolymers. The hydrodynamic radii of the synthesized graft copolymers were both dependent on the temperature and pH value. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3797–3804, 2001  相似文献   

7.
A series of novel pyrrolo‐allocolchicine derivatives (containing a 1‐methyl‐1H‐indol‐5‐yl moiety replacing ring C) was synthesized. The tetracyclic ring system was constructed by Suzuki–Miyaura cross‐coupling of a 1‐methylindole‐5‐boronate with an ortho‐iodo‐dihydrocinnamic acid derivative and subsequent intramolecular Friedel–Crafts acylation. After reduction of the resulting ketone, the nitrogen functionality was introduced in a Mitsunobu‐type reaction by using zinc azide followed by LiAlH4 reduction. Structural assignments were supported by X‐ray crystallography. The compounds synthesized were then tested against BJAB tumor cells and found to exhibit pronounced cytotoxic activity (proliferation inhibition and apoptosis induction). The ketone 24 b was even active at sub‐nanomolar concentration. In addition, the antitumor potential of the compounds was confirmed by using B lymphoid cell lines.  相似文献   

8.
Cyclic alkenylsiloxanes were synthesized by semihydrogenation of alkynylsilanes—a reaction previously plagued by poor stereoselectivity. The silanes, which can be synthesized on multigram scale, undergo Hiyama–Denmark coupling to give (Z)‐alkenyl polyene motifs found in bioactive natural products. The ring size of the silane is crucial: five‐membered cyclic siloxanes also couple under fluoride‐free conditions, whilst their six‐membered homologues do not, enabling orthogonality within this structural motif.  相似文献   

9.
A new donor–acceptor (D–A) conjugated copolymer based on benzo[1,2‐b:4,5‐b′]dithiophene (BDT) and thieno[3,4‐c]pyrrole‐4,6‐dione (TPD) was synthesized via a Stille cross‐coupling reaction. A highly conjugated thiophene‐based side group, tris(thienylenevinylene) (TTV), was incorporated into each BDT unit to generate the two‐dimensional D–A copolymer (PBDT‐TTV). An alkoxy‐substituted BDT‐based TPD copolymer (PBDT‐OR) was synthesized using the same polymerization method for comparison. PBDT‐TTV thin films produced two distinct absorption peaks. The shorter wavelength absorption (458 nm) was attributed to the BDT units containing the TTV group, and the longer wavelength band (567–616 nm) was attributed to intramolecular charge transfer between the BDT donor and the TPD acceptor. The highest occupied molecular orbital energy levels of PBDT‐OR and PBDT‐TTV were calculated to be −5.53 and −5.61 eV, respectively. PBDT‐TTV thin films harvested a broad solar spectrum covering the range 300–700 nm. A comparison with the PBDT‐OR films revealed stronger interchain π–π interactions in the PBDT‐TTV films and, thus, a higher hole mobility. A polymer solar cell device prepared using PBDT‐TTV as the active layer was found to exhibit a higher power conversion efficiency than a device prepared using PBDT‐OR under AM 1.5 G (100 mW/cm2) conditions. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 653–660  相似文献   

10.
In an attempt to synthesize antibacterial agents effective against gram‐positive and gram‐negative bacteria, the efficient synthesis of novel bis‐azetidinones ( 3a–j ) has been established. Thus, cycloaddition reaction of substituted bis‐imines with chloroacetylchloride under microwave irradiation in the presence of zeolite yielded bis‐azetidinones ( 3a–j ). Structures of the synthesized compounds have been elucidated on the basis of their elemental analysis and spectral data (IR, 1H‐NMR, 13C‐NMR, and mass spectra). The synthesized bis‐azetidinones were screened for their antibacterial activity against five microorganisms: Bacillus subtilis, Proteus vulgaris, Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli. They were found to exhibit good to moderate antibacterial activity.  相似文献   

11.
Amphiphilic, biocompatible poly(N‐vinylpyrrolidone)‐b‐poly(l ‐lactide) (PVP‐b‐PLLA) block polymers were synthesized at 60 °C using a hydroxyl‐functionalized N,N‐diphenyldithiocarbamate reversible addition–fragmentation chain transfer (RAFT) agent, 2‐hydroxyethyl 2‐(N,N‐diphenylcarbamothioylthio)propanoate (HDPCP), as a dual initiator for RAFT polymerization and ring‐opening polymerization (ROP) in a one‐step procedure. 4‐Dimethylamino pyridine was used as the ROP catalyst for l ‐lactide. The two polymerization reactions proceeded in a controlled manner, but their polymerization rates were affected by the other polymerization process. This one‐step procedure is believed to be the most convenient method for synthesizing PVP‐b‐PLLA block copolymers. HDPCP can also be used for the one‐step synthesis of poly(N‐vinylcarbazole)‐b‐PLLA block copolymers. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1607–1613  相似文献   

12.
Poly(o‐methoxyaniline) (POMA) and poly(o‐toluidine) (POT) salts doped with different acids (methanesulphonic acid (MeSA), trifluoroacetic acid (TFA), and hydrochloric acid (HCl)) were synthesized by using solid‐state polymerization method. The polymers were characterized by Fourier transform infrared (FTIR) spectra, ultraviolet–visible (UV–Vis) spectrometry, X‐ray diffraction (XRD), cyclic voltammetry (CV), and conductivity measurements. Transmission electron microscopy (TEM) was done to study the morphologies of POMA and POT salts. The FTIR and UV‐Vis absorption spectra revealed that the reduced phase was predominant in POMA salts, and the pernigraniline phase was predominant in POT salts. It was found that POMA salts displayed higher doping level and conductivity. In contrast, POT salts were lower at doping levels and conductivity. In accordance with these results, the electrochemical activity was also found to be lower in POT salts. The XRD patterns showed that the POMA salts displayed higher crystallinity than POT salts. The results from TEM revealed that the morphologies of POMA salts were different from those of POT salts. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

13.
A bisphenol bearing pendant maleimide group, namely, N‐maleimidoethyl‐3, 3‐bis(4‐hydroxyphenyl)‐1‐isobenzopyrrolidone (PPH‐MA) was synthesized starting from phenolphthalein. Aromatic (co)polyesters bearing pendant maleimide groups were synthesized from PPH‐MA and aromatic diacid chlorides, namely, isophthaloyl chloride (IPC), terephthaloyl chloride (TPC), and 50:50 mol % mixture of IPC and TPC by low temperature solution polycondensation technique. Copolyesters were also synthesized by polycondensation of different molar proportions of PPH‐MA and bisphenol A with IPC. Inherent viscosities and number‐average molecular weights of aromatic (co)polyesters were in the range of 0.52–0.97 dL/g and 20,200–32,800 g/mol, respectively indicating formation of medium to reasonably high‐molecular‐weight polymers. 13C NMR spectral analysis of copolyesters revealed the formation of random copolymers. The 10% weight loss temperature of (co)polyesters was found in the range 470–484 °C, indicating their good thermal stability. A selected aromatic polyester bearing pendant maleimide groups was chemically modified via thiol‐maleimide Michael addition reaction with two representative thiol compounds, namely, 4‐chlorothiophenol and 1‐adamantanethiol to yield post‐modified polymers in a quantitative manner. Additionally, it was demonstrated that polyester containing pendant maleimide groups could be used to form insoluble crosslinked gel in the presence of a multifunctional thiol crosslinker. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 630–640  相似文献   

14.
4‐Triphenylmethyl‐1,2‐benzoquinone (TPMBQ) reacted with some metal ions and the structure of the new compounds had been identified. The metal to ligand ratio was 1:2 which was revealed by elemental analysis. The complexes were found to have octahedral geometry and their thermal stability was studied using thermogravimetric analysis technique. The molar conductance measurements revealed the electrolytic nature of the synthesized chelates. The IR spectra concluded the bidentate nature of the TPMBQ ligand while the 1H NMR revealed the presence of water molecules. The XRD spectra of Mn (II) and Fe (III) complexes concluded their crystalline structure while Co (II) and Cu (II) chelates refer to amorphous structures. The geometries of the TPMBQ ligand were optimized using Gaussian 09 W; density functional theory B3LYP method. (DFT)/basis set 6–311++G (d, p). HOMO and LUMO energy values for chelates, chemical hardness and electro‐negativity had been calculated. The ligand and its metal complexes had been examined against different kinds of bacteria such as Proteus vulgaris, Escherichia coli, Staphylococcus aurous and Bacillus subtitles to examine their antimicrobial activity. Molecular docking using Auto Dock tools were utilized.  相似文献   

15.
In this study, donor‐acceptor type thiophene‐perylene‐thiophene monomers were synthesized and polymerized by both oxidative polymerization using FeCl3 as catalyst and the electrochemical process. UV–vis, FTIR, 1H NMR, and elemental analysis techniques were used for structural characterization. Thermal behaviors of these compounds were determined by using TGA system. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels and electrochemical and optical band gap values were calculated by using the results of cyclic voltammetry and UV–vis measurements, respectively. The number–average molecular weight (Mn), weight–average molecular weight (Mw), and polydispersity index (PDI) values of synthesized polymers were determined by size exclusion chromatography. Conductivity measurements of these polymers were carried out by electrometer by using a four‐point probe technique. The conductivity was observed to be increased by iodine doping. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1974–1989, 2008  相似文献   

16.
《中国化学会会志》2003,50(2):273-278
Spiro[indole‐pyranoimidazoles] ( 5 ) and spiro[indole‐pyranobenzopyrans] ( 6 ) are readily synthesized in one step in 86–92 and 91–97% yields by the Michael condensation of 3‐dicyanomethylene‐2H‐indol‐2‐ones ( 2 ) with 1‐phenyl‐2‐thiohydantoin ( 3 ) and 4‐hydroxy‐2H‐1‐benzopyran‐2‐one ( 4 ), respectively, without using any catalyst under different reaction conditions (conventional heating and microwave irradiation using (a) polar solvents (b) neutral alumina/silica gel as inorganic solid support in solvent free conditions). 2 was synthesized in situ by the Knoevenagel condensation of indole‐2,3‐dione ( 1 ) and malononitrile in the absence of any catalyst. 100% conversion was observed in most cases on TLC which also showed the formation of a single product. The comparison between the various methods is established.  相似文献   

17.
A new series of pyrazolone based azo acid dyes (3a–g) has been synthesized starting from 1‐(p‐sul‐phophenyl)‐3‐methyl‐5‐pyrazolone (1). The synthetic methodology included the nitrosation of p‐sulphophenyl methyl pyrazolone followed by reduction, diazotization and coupling with Naphthol AS derivatives (2a–f), in alkaline medium to yield different acid dyes. Multichromic metal complexes of these dyes (5a–f, 6a–f and 7a–f) with 3d transition metals Chromium, Iron and Copper were also synthesized. The structures of all of newly synthesized compounds were confirmed by analytical data and spectroscopic techniques. The synthesized dyes were applied on leather to assess their light fastness, wash fastness and rubbing fastness and were shown to exhibit high values of 4–5 for majority of dyes.  相似文献   

18.
A series of an ionic hydrogels composed of N,N‐diethylaminoethyl methacrylamide (DEAEMA), N‐vinyl‐2‐pyrrolidone (VP), and itaconic acid were synthesized by free‐radical cross‐linking copolymerization in water–ethanol mixture by using N,N‐methylenebis(acrylamide) as the cross‐linker, ammonium persulfate as the initiator, and N,N,N′,N′‐tetramethylenediamine as the activator. The swelling behaviors of these hydrogels were analyzed in buffer solutions at various pH. It was observed that the swelling behavior of cross‐linked ionic poly(N,N‐diethylaminoethyl methacrylamide‐coN‐vinyl‐2‐pyrrolidone) [P(DEAEMA/VP)] hydrogels at different pH agreed with the modified Flory–Rehner equation based on the affine network model and the ideal Donnan theory. The swelling process in buffer solutions at various pH was found to be Fickian‐type diffusion. The pH‐reversibility and on–off switching properties of the P(DEAEMA/VP) hydrogels may be considered as good candidate to design novel drug‐delivery system. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2819–2828, 2005  相似文献   

19.
9,9‐Bis(3‐methyl‐4‐hydroxyphenyl)xanthene (BMHPX) was synthesized in 72% yield by a HCl/ZnCl2‐catalyzed condensation reaction of xanthenone with excess o‐cresol. Based on this new bisphenol monomer, a series of poly(arylene ether nitrile) (PAEN) and PAEN copolymers containing methyl substituent and cardo xanthene moiety were prepared by the nucleophilic substitution reaction of 2,6‐difluorobenzonitrile (DFBN) with BMHPX and with varying mole proportions of BMHPX to hydroquinone (HQ) (100/0–40/60) using N‐methyl‐2‐pyrrolidone (NMP) as solvent in the presence of anhydrous potassium carbonate. These polymers had inherent viscosities between 0.54 and 0.72 dl/g, and their weight‐average molecular weights and number‐average molecular weights were in the range of 32,600–36,400 and 17,300–18,300, respectively. All PAENs were amorphous and were soluble in dipolar aprotic solvents such as NMP and N,N‐dimethylacetamide (DMAc), and even in THF and chloroform at room temperature. The resulting polymers showed glass transition temperatures (Tg's) between 213–226°C, and the Tg values of the copolymers were found to increase with increase of the BMHPX units content in the polymer. Thermogravimetric studies showed that all the polymers were stable up to 404°C, with 10% weight loss temperatures ranging from 444 to 455°C, and char yields of 52–58% at 700°C in nitrogen. All new PAENs could be cast into transparent, strong, and flexible films with tensile strengths of 102–120 MPa, elongations at break of 14–18%, and tensile moduli of 3.3–3.7 GPa. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

20.
Ethylene polymerizations were performed using catalyst based on titanium tetrachloride (TiCl4) supported on synthesized poly(methyl acrylate‐co‐1‐octene) (PMO). Three catalysts were synthesized by varying TiCl4/PMO weight ratio in chlorobenzene resulting in incorporation of titanium in different percentage as determined by UV‐vis spectroscopy. The coordination of titanium with the copolymer matrix was confirmed by FTIR studies. The catalysts morphology as observed by SEM was found to be round shaped with even distributions of titanium and chlorine on the surface of catalyst. Their performance was evaluated for atmospheric polymerization of ethylene in n‐hexane using triethylaluminum as cocatalyst. Catalyst with titanium incorporation corresponding to 2.8 wt % showed maximum activity. Polyethylenes obtained were characterized for melting temperature, molecular weight, morphology and microstructure. The polymeric support utilized for TiCl4 was synthesized using activators regenerated by electron transfer (ARGET) Atom Transfer Radical Polymerization (ATRP) of methyl acrylate (MA) and 1‐octene (Oct) with Cu(0)/CuBr2/tris(2‐(dimethylamino)ethyl)amine (Me6TREN) as catalyst and ethyl 2‐bromoisobutyrate (EBriB) as initiator at 80 °C. The copolymer poly(methyl acrylate‐1‐octene; PMO) obtained showed monomodal curve in Gel Permeation Chromatography (GPC) with polydispersity of 1.37 and copolymer composition (1H NMR; FMA) of 0.75. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7299–7309, 2008  相似文献   

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