Di-2,2,2-trifluoro-1-(9-anthryl)ethyl fumarate,an easy starting point for the enantioselective preparation of trans-cyclohexene-4,5-dicarboxylate derivatives by Diels–Alder reaction

Di-2,2,2-trifluoro-1-(9-anthryl)ethyl fumarate has been synthesized from fumaric acid and enantiopure Pirkle alcohol. The Diels–Alder reaction with different dienes employing different reaction conditions was assayed, with high diastereomeric excesses obtained. The structure and geometry of the cycloadducts was analyzed by NMR, molecular mechanics and X-ray diffraction. Hydrolysis made it possible to obtain the enantioenriched trans-cyclohexene-4,5-dicarboxylate derivatives and allow us to recover chiral auxiliary.     

Preparation of 3‐arm star polymers (A3) via Diels–Alder click reaction

Diels–Alder click reaction was successfully applied for the preparation of 3‐arm star polymers (A₃) using furan protected maleimide end‐functionalized polymers and trianthracene functional linking agent (2) at reflux temperature of toluene for 48 h. Well‐defined furan protected maleimide end‐functionalized polymers, poly (ethylene glycol), poly(methyl methacrylate), and poly(tert‐butyl acrylate) were obtained by esterification or atom transfer radical polymerization. Obtained star polymers were characterized via NMR and GPC (refractive index and triple detector detection). Splitting of GPC traces of the resulting polymer mixture notably displayed that Diels–Alder click reaction was a versatile and a reliable route for the preparation of A₃ star polymer. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 302–313, 2008     

Radical polymerization of various alkyl methacrylates in liquid crystalline solvents

The polymerization of methacrylates of methyl, ethyl, butyl, hexyl, octyl, dodecyl, and octadecyl alcohols was studied with 2,2′-azobisisobutyronitrile in the smectic, nematic, cholesteric, and isotropic liquid phases at 50–75°C. N-(4-Methoxyphenylmethylene)phenylamine, N-(4-ethoxyphenyl-methylene)-4-butylphenylamine, cholesteryl octadecanoate, and benzene were used as the solvents. The viscosities of the polymers were enhanced in the mesomorphic solvents. The polymer was converted to the corresponding poly(methyl methacrylate) through hydrolysis and esterification. Tacticities of the resultant poly(methyl methacrylates) were determined by nuclear magnetic resonance spectroscopy. The isotacticities of the polymers obtained in the smectic and the nematic phases were basically the same and appeared to be larger than those of the polymers in the cholesteric and isotropic liquid states. The polymerization of the methacrylates of butyl and longer-chain alcohols deviated from Bernoullian statistics and gave polymers more isotactic than those of methyl and ethyl methacrylates.     

<Emphasis Type="Italic">N,N′</Emphasis>-Bis(9-anthrylmethyl)diamines as fluorescent chemosensors for transition metal cations

N,N′-Bis(9-anthryl)-substituted diamines, imidazolidines, and hexahydropyrimidines were synthesized, and their luminescence properties and complexing ability were studied. N,N′-Bis(9-anthrylmethyl)ethane-1,2-diamine and N,N′-bis(9-anthrylmethyl)butane-1,4-diamine were found to be effective and selective PET chemosensors for Zn²⁺ and H⁺, respectively. 2-[1,3-Bis(9-anthrylmethyl)hexahydropyrimidin-2-yl]-6-methoxyphenol can be used as fluorescent chemosensor for mercury(II) cations.     

Diels–Alder Reactions of 1,2‐Azaborines

Diels–Alder reactions employing 1,2‐azaborine heterocycles as 1,3‐dienes are reported. Carbocyclic compounds with high stereochemical and functional complexity are produced, as exemplified by the straightforward two‐step synthesis of an amino allyl boronic ester bearing four contiguous stereocenters as a single diastereomer. Whereas electron‐deficient dienophiles undergo irreversible Diels–Alder reactions, a reversible Diels–Alder reaction with the less electron‐deficient methyl acrylate is observed. Both the N and the B substituent of the 1,2‐azaborine exert significant influence on the [4+2] cycloaddition reactivity as well as the aromatic character of the heterocycle. The experimentally determined thermodynamic parameters of the reversible Diels–Alder reaction between 1,2‐azaborines and methyl acrylate correlate with aromaticity trends and place 1,2‐azaborines approximately between furan and thiophene on the aromaticity scale.     

Development of Carbazole and Bipyridine Copolymers as Novel Photovoltaic Materials

Summary: A novel acrylate polymer with a carbazole pendant group and bipyridine derivatives as side chains was synthesized, in which derivatives of bipyridine as electro-optic chromophores and carbazole as photoconductive moiety were covalently linked to the acrylate backbone. 2–(Carbazol-9-yl)ethyl methacrylate (CEM) and methacrylic 2-[5-(2-{5,5′-dimethyl-6′-[2-(5-pentylthiophen-2-yl)vinyl]-3,3′-bipyridin-6-yl}vinyl)thiophen-2-yl]ethyl methacrylate (BiPy) were synthesized and then copolymerized to give 99:1, 98:2, 92:8 (mol/mol) CEM/BiPy copolymers. Films of the copolymers blended with poly(3-octylthiophene) (P3OT) or poly(3-decylthiophene) (PDT) and sandwiched between the transparent ITO and Al electrode were examined for photovoltaic properties.     

Thermally amendable tailor‐made functional polymer by RAFT polymerization and “click reaction”

This investigation reports the preparation and characterization of thermally amendable functional polymer bearing furfuryl functionality via reversible‐addition fragmentation and chain transfer (RAFT) polymerization and Diels‐Alder (DA) reaction. In this case, furfuryl methacrylate (FMA) was polymerized using 4‐cyano‐4‐[(dodecylsulfanylthiocarbonyl)sulfanyl] pentanoic acid as RAFT reagent and 4,4′‐azobis(4‐cyanovaleric acid) as thermal initiator. ¹H NMR, ¹³C NMR, and matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry analysis showed that furfuryl group in poly(furfuryl methacrylate) (PFMA) was not affected during RAFT polymerization and the tailor‐made polymer had RAFT end group. The DA reaction was successfully carried out between the reactive furfuryl functionality of PFMA and different bismaleimides. The thermoreversible property of these DA polymers was characterized by FT‐IR and DSC analysis. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 3365–3374     

New initiator system for the anionic polymerization of (meth)acrylates in toluene. IV. Random copolymerization of (meth)acrylates in toluene initiated by s-BuLi ligated by lithium silanolates

Copolymerization of binary mixtures of alkyl (meth)acrylates has been initiated in toluene by a mixed complex of lithium silanolate  (s-BuMe₂SiOLi) and s-BuLi (molar ratio > 21) formed in situ by reaction of s-BuLi with hexamethylcyclotrisiloxane (D₃). Fully acrylate and methacrylate copolymers, i.e., poly(methyl acrylate-co-n-butyl acrylate), poly(methyl methacrylate-co-ethyl methacrylate), poly(methyl methacrylate-co-n-butyl methacrylate), poly(methyl methacrylate-co-n-butyl methacrylate), poly(isobornyl methacrylate-co-n-butyl methacrylate), poly(isobornyl methacrylate-co-n-butyl methacrylate) of a rather narrow molecular weight distribution have been synthesized. However, copolymerization of alkyl acrylate and methyl methacrylate pairs has completely failed, leading to the selective formation of homopoly(acrylate). As result of the isotactic stereoregulation of the alkyl methacrylate polymerization by the s-BuLi/s-BuMe₂SiOLi initiator, highly isotactic random and block copolymers of (alkyl) methacrylates have been prepared and their thermal behavior analyzed. The structure of isotactic poly(ethyl methacrylate-co-methyl methacrylate) copolymers has been analyzed in more detail by Nuclear Magnetic Resonance (NMR). © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2525–2535, 1999     

Synthesis and polymerization of phosphorus‐containing acrylates

Novel phosphorus‐containing acrylate monomers were synthesized by two different routes. The first involved the reaction of ethyl α‐chloromethyl acrylate and t‐butyl α‐bromomethyl acrylate with diethylphosphonoacetic acid. The monomers were bulk‐ and solution‐polymerized at 56–64 °C with 2,2′‐azobisisobutyronitrile. The ethyl ester monomer showed a high crosslinking tendency under these conditions. The selective hydrolysis of the ethyl ester phosphonic ester compound was carried out with trimethylsilyl bromide, producing a phosphonic acid monomer. In the second route, ethyl α‐hydroxymethyl acrylate and t‐butyl α‐hydroxymethyl acrylate were reacted with diethylchlorophosphate. The bulk homopolymerization and copolymerization of these monomers with methyl methacrylate and 2,2′‐azobisisobutyronitrile gave soluble polymers. The attempted hydrolysis of the monomers was unsuccessful because of the loss of the diethylphosphate group. The relative reactivities of the monomers in the photopolymerizations were also compared. The ethyl α‐hydroxymethyl acrylate/diethylphosphonic acid monomer showed higher reactivity than the other monomers, which may explain the crosslinking during the polymerization of this monomer. The reactivities of other derivatives were similar, but the rates of polymerization were slow in comparison with those of methyl methacrylate. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3221–3231, 2002     

A Diels-Alder Approach to 4,4′-Ihiobis-(Phihalic Acid) Derivatives

Reactions of 3,3′-thiobis(2,5-dihydrothiophene 1,1 dioxide) (2) with several dienophiles afforded Diels Alder adducts 4–7. Compound 7 was aromatized to give 4,4′-thio-bis(dimethyl phthalate) (9), a potential intermediate to sulfur- bridged polyimides.     

Preparation of a Porous polymer by a catalyst‐free diels‐alder reaction and its structural modification by post‐reaction

A microporous polymer is prepared by a catalyst‐free Diels–Alder reaction. A cyclopentadiene with both a diene and a dienophile functionality and a dienophilic maleimide are used for the Diels–Alder reaction. 1,3,5‐Tris(bromomethyl)‐2,4,6‐trimethylbenzene is reacted with sodium cyclopentadienide to produce the multicyclopentadiene‐functionalized monomer. A crosslinked polymer ( CDAP ) is obtained by the reaction of the cyclopentadiene monomer with N,N′‐1,4‐phenylenedimaleimide. The thermal dissociation of the cyclopentadiene dimeric unit and the subsequent Diels–Alder reaction with the maleimide group are investigated by the model reaction. We are able to restructure the crosslinked polymer network by taking advantage of the thermal reversibility of the Diels–Alder linkage. After the post thermal treatment, the BET surface area of the polymer ( CDAP‐T ) is greatly increased from 317 to 1038 m² g^?1. CDAP‐T is functionalized with pyrene by bromination with N‐bromosuccinimide and the subsequent substitution reaction with aminopyrene. The adsorption property of the pyrene‐functionalized polymer for an aromatic dye is investigated using malachite green. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3646–3653     

Heteroarm H‐shaped terpolymers through the combination of the Diels–Alder reaction and controlled/living radical polymerization techniques

Heteroarm H‐shaped terpolymers (PS)(PtBA)–PEO–(PtBA)(PS) and (PS)(PtBA)–PPO–(PtBA)(PS) [where PS is polystyrene, PtBA is poly(tert‐butyl acrylate), PEO is poly(ethylene oxide), and PPO is poly(propylene oxide)], containing PEO or PPO as a backbone and PS and PtBA as side arms, were prepared via the combination of the Diels–Alder reaction and atom transfer radical and nitroxide‐mediated radical polymerization routes. Commercially available PEO or PPO containing bismaleimide end groups was reacted with a compound having an anthracene functionality, succinic acid anthracen‐9‐yl methyl ester 3‐(2‐bromo‐2‐methylpropionyloxy)‐2‐methyl‐2‐[2‐phenyl‐2‐(2,2,6,6‐tetramethylpiperidin‐1‐yloxy)ethoxycarbonyl]propyl ester, with a Diels–Alder reaction strategy. The obtained macroinitiator with tertiary bromide and 2,2,6,6‐tetramethylpiperidin‐1‐oxy functional end groups was used subsequently in the atom transfer radical polymerization of tert‐butyl acrylate and in the nitroxide‐mediated free‐radical polymerization of styrene to produce heteroarm H‐shaped terpolymers with moderately low molecular weight distributions (<1.31). The polymers were characterized with ¹H NMR, ultraviolet, gel permeation chromatography, and differential scanning calorimetry. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3947–3957, 2006     

Synthesis of traditional and ionic polymethacrylates by anion catalyzed group transfer polymerization

The hydrophobic ionic liquid 1‐butyl‐1‐methylpyrrolidinium bis(trifluoromethylsulfonyl)imide was successfully used as solvent in group transfer polymerization of traditional methacrylates (methyl methacrylate, n‐butyl methacrylate, and benzyl methacrylate) and of ionic liquid methacrylates (ILMAs). This demonstrates that this ionic liquid makes reaction conditions, which do not require the use of ultra‐dried solvents. The ILMAs were N‐[2‐(methacryloyloxy)ethyl]‐N,N‐dimethyl‐N‐alkylammonium bis(trifluoromethylsulfonyl)imides bearing methyl, ethyl, propyl, butyl, or hexyl substituents. Increasing size of the alkyl substituent at the cation results in decreasing glass transition temperature in case of both ionic liquid methacrylates and polymers derived of them. Furthermore, the glass transition temperature is significantly higher for these polymers compared with the ionic liquid methacrylates, and the effect of glass transition temperature reduction with increasing size of the alkyl substituent is stronger for the polymers. A mechanism was proposed explaining the catalytic function of the ionic liquid used as solvent for polymerization. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2849–2859     

A Diels‐Alder/retro Diels‐Alder strategy to synthesize polymers bearing maleimide side chains

Polymers containing thiol‐reactive maleimide groups on their side chains have been synthesized by utilization of a novel methacrylate monomer containing a masked maleimide. Diels‐Alder reaction between furan and maleimide was adapted for the protection of the reactive maleimide double bond prior to polymerization. AIBN initiated free radical polymerization was utilized for synthesis of copolymers containing masked maleimide groups. No unmasking of the maleimide group was evident under the polymerization conditions. The maleimide groups in the side chain of the polymers were unmasked into their reactive form by utilization of retro Diels‐Alder reaction. This cycloreversion was monitored by thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), and ¹H and ¹³C NMR spectroscopy. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4545–4551, 2007     

Preparation of block copolymers via Diels Alder reaction of maleimide‐ and anthracene‐end functionalized polymers

A number of diblock copolymers were successfully prepared by Diels–Alder reaction, between maleimide‐ and anthracene‐end functionalized poly (methyl methacrylate) (PMMA), polystyrene (PS), poly(tert‐butyl acrylate) (PtBA), and poly(ethylene glycol) (PEG) in toluene, at 110 °C. For this purpose, 2‐bromo‐2‐methyl‐propionic acid 2‐(3,5‐dioxo‐10‐oxa‐4‐azatricyclo[5.2.1.02,6]dec‐8‐en‐4‐yl)‐ethyl ester, 2 , 9‐anthyrylmethyl 2‐bromo‐2‐methyl propanoate, 3 , and 2‐bromo‐propionic acid 2‐(3,5‐dioxo‐10‐oxa‐4‐azatricyclo[5.2.1.02,6]dec‐8‐en‐4‐yl)‐ethyl ester, 4 , were used as initiators in atom transfer radical polymerization, in the presence of Cu(I) salt and pentamethyldiethylenetriamine (PMDETA), at various temperatures. On the other hand, PEG with maleimide‐ or anthracene‐end functionality was achieved by esterification between monohydroxy PEG and succinic acid monoathracen‐9‐ylmethyl ester, 1 , or 4‐maleimido‐benzoyl chloride. Thus‐obtained PMMA‐b‐PS, PEG‐b‐PS, PtBA‐b‐PS, and PMMA‐b‐PEG block copolymers were characterized by ¹H NMR, UV, and GPC. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1667–1675, 2006     

Comparison of surface confined ATRP and SET‐LRP syntheses for a series of amino (meth)acrylate polymer brushes on silicon substrates

A series of poly(amino (meth)acrylate) brushes, poly(2‐(dimethylamino)ethyl methacrylate) (PDMAEMA), poly(2‐(diethylamino)ethyl methacrylate) (PDEAEMA), poly(2‐(dimethylamino)ethyl acrylate) (PDMAEA), poly(2‐(tert‐butylamino)ethyl methacrylate) (PTBAEMA), has been synthesized via surface‐confined controlled/living radical polymerizations using surface‐confined initiator from silane self‐assembled monolayers (SAMs) on silicon (Si) wafer substrates. Chemical methods and efficacies for two types of living radical polymerization, atom transfer radical (ATRP) and single electron transfer (SET‐LRP), are described and contrasted for the surface confined polymerization of poly(amino (meth)acrylate)s. Effects of solvent, catalyst/ligand system, and temperature on polymerization success were examined. Chemical compositions after each reaction step were characterized with FTIR spectroscopy, contact angle goniometry, and X‐ray photoelectron spectroscopy while the SAM and polymer brush thicknesses were measured with spectroscopic ellipsometry. For the first time, this study demonstrates successful surface‐confined polymerization of a series of poly(amine (meth)acrylate) brushes from Si‐SAM substrates using a copper metal electron donor catalyst. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6552–6560, 2009     

Simple and Efficient Purification Protocol of 9-(Trifluoroacetyl)anthracene from Anthracene

A protocol has been developed to purify 9-(trifluoroacetyl)anthracene from anthracene, the major impurity associated in its synthesis. The protocol utilizes a chemoselective thermal Diels–Alder reaction, employing maleic anhydride as the dienophile. The resulting Diels–Alder adduct can then be removed by extractive workup followed by recrystallization to give 9-(trifluoroacetyl)anthracene with ≥99% chemical purity.     

Controlled radical polymerization of anthracene‐containing methacrylate copolymers for stimuli‐responsive materials

Novel reversible networks utilizing photodimerization of crosslinkable anthracene groups and thermal dissociation were investigated. Reversible addition‐fragmentation chain transfer polymerization yielded well‐defined copolymers with 9‐anthrylmethyl methacrylate (AMMA) and other alkyl methacrylates such as methyl methacrylate (MMA) and 2‐ethylhexyl methacrylate (EHMA) having different AMMA compositions. Well‐controlled block copolymerization of AMMA and alkyl methacrylates was also successfully accomplished using a trithiocarbonate‐terminated poly(alkyl methacrylate) macro‐chain transfer agent. The anthracene‐containing copolymers showed reversibility via crosslinking based on photodimerization with ultraviolet irradiation and subsequent thermal dissociation. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2302–2311     

Vinyl polymerization initiated by reducing compounds of transition metals—5. Graft copolymerization of chlorine containing polymers by vanadium(III) chloride

Graft copolymerization of methyl methacrylate (MMA) on chlorine containing polymers [e.g. trichloroacetates of poly(vinyl alcohol), microcrystalline cellulose or starch and chlorinated atactic polypropylene] in the presence of vanadium(III) chloride (VCl₃) was carried out in dimethylformamide at 70°. The grafting n-butyl methacrylate or ethyl acrylate on poly(vinyl trichloroacetate) displayed high efficiency; in the first system, however, crosslinked polymer fractions were formed. The number-average molecular weight of grafted branches was determined. Chromium(II) acetate and titanium(III) chloride are less efficient initiators for polymerization of methacrylates in the presence of trichloroacetates.     

Preparation and characterization of a novel fluorinated acrylate resin

The novel fluorinated acrylate resin was successfully prepared by solution polymerization of 2-(perfluoro-(1,1-bis-isopropyl)-2-propenyl)oxyethyl methacrylate (POMA) with butyl acrylate (BA), methyl methacrylate (MMA) and methacrylic acid (MAA) initiated by AIBN in the co-solvents of ethyl acetate, butyl alcohol and toluene. POMA was synthesized from the intermediate perfluoro nonene and 2-hydroxyethyl methacrylate as the staring reactants. Films of the novel fluorinated acrylate resin were prepared by coating the resin directly on the clean glass sheet and allowed to dry at room temperature. The characteristics of the film such as hydrophobicity, glass transition temperature and thermal stability were characterized with the contact angle, differential scanning calorimetry and thermo-gravimetric analysis respectively. The structure of the novel fluorinated acrylate resin was investigated by Fourier transform infrared (FTIR) spectrometry. The influences of the fluorine content on the performance of the acrylate resin were studied. Results show that the hydrophobicity, chemical resistance, glass transition temperature and thermal stability of the acrylate resin are improved when the fluorinated monomer is introduced to copolymerize with other monomers. However, the hydrophobicity of the fluorinated acrylate resin is improved slightly via annealing.