SYTHESIS AND ANIONIC POLYMERIZATION OF 2-METHYL-2-METHOXYCARBONYL-5-METHYLENE-1, 3-DIOXOLAN-4-ONE

A new cyclic monomer, 2-methyl-2-methoxycarbonyl-5-methylene-1,3-dioxolan-4-one,was synthesized successfully. The monomer and intermediate were characterized by ~1H NMR, ~(13)CNMR, INEPT(Intensive Nuclei Enhanced by Polarization Transfer) technique, IR and elementalanalysis. Anionic polymerization of the monomer was carried out in anhydrous THF at -70℃,and 9-fluorenyllithium was used as initiator. The polymer structure was determined by IR, NMRand elemental analysis. Molecular weight of the polymer was estimated by viscosity measurementin DMSO at 30℃.     

SYNTHESIS AND POLYMERIZATION OF 2-OXO-3-METHYLENE-5, 6-DIPHENYL-1,4-DIOXAN

A new cyclic monomer, 2-oxo-3-methylene-5, 6-diphenyl-1, 4-dioxan, was synthesized. Thestructure of the intermediates and the monomer were determined by IR,~1H NMR,~(13)C NMR andelemental analysis. This new monomer is different from other cyclic monomers in this series,it isa solid (mp 108--109℃)and not very reactive, but still can undergo free radical ring-openingpolymerization. The free radical polymerization was carried out at 130℃. The structure of theresulting polymer was discussed and charaterized by IR, ~1H NMR, ~(13)C NMR and elementalanalysis. The molecular weight of the polymer was estimated by viscosity determination.     

Synthesis and characterization of mono‐ and di‐methoxy substituted acrylate polymers containing photocrosslinkable pendant chalcone moiety

Two acrylate monomers – 4‐(2′‐methoxycinnamoyl)phenyl acrylate, and 4‐(2′,5′‐dimethoxycinnamoyl)phenyl acrylate – comprising photocrosslinkable pendant chalcone moiety and a free radical polymerizable group were synthesized. The monomers were polymerized in the presence of ethyl methyl ketone at 70°C using benzoyl peroxide as the initiator. The polymers were characterized by UV, FT‐IR, ¹H‐NMR, and ¹³C‐NMR spectra. The weight and number average molecular weights of the polymers were determined by gel permeation chromatography. The thermal stability of the polymers was studied by TGA under a nitrogen atmosphere. Glass transition temperatures of the polymers were studied by differential scanning calorimetry. The photoreactivity of the polymers was investigated for potential applications as photoresists in solution using various solvents. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis of degradable and chemically recyclable polymers using 4,4-disubstituted five-membered cyclic ketene hemiacetal ester (CKHE) monomers

Novel degradable and chemically recyclable polymers were synthesized using five-membered cyclic ketene hemiacetal ester (CKHE) monomers. The studied monomers were 4,4-dimethyl-2-methylene-1,3-dioxolan-5-one (DMDL) and 5-methyl-2-methylene-5-phenyl-1,3-dioxolan-4-one (PhDL). The two monomers were synthesized in high yields (80–90%), which is an attractive feature. DMDL afforded its homopolymer with a relatively high molecular weight (M_n >100 000, where M_n is the number-average molecular weight). DMDL and PhDL were copolymerized with various families of vinyl monomers, i.e., methacrylates, acrylates, styrene, acrylonitrile, vinyl pyrrolidinone, and acrylamide, and various functional methacrylates and acrylate. Such a wide scope of the accessible polymers is highly useful for material design. The obtained homopolymers and random copolymers of DMDL degraded in basic conditions (in the presence of a hydroxide or an amine) at relatively mild temperatures (room temperature to 65 °C). The degradation of the DMDL homopolymer generated 2-hydroxyisobutyric acid (HIBA). The generated HIBA was recovered and used as an ingredient to re-synthesize DMDL monomer, and this monomer was further used to re-synthesize the DMDL polymer, demonstrating the chemical recycling of the DMDL polymer. Such degradability and chemical recyclability of the DMDL polymer may contribute to the circular materials economy.

Novel degradable and chemically recyclable polymers were synthesized using five-membered cyclic ketene hemiacetal ester (CKHE) monomers.     

Synthesis of 1,3-Dioxolane Derivatives from β-Chlorolactic Acid and Ketones

2-Ethyl-2-methyl-5-methylene-1,3-dioxolan-4-one and 5-methylene-2,2-pentamethylene-1,3-dioxolan-4-one were synthesized by reaction of -chlorolactic acid with methyl ethyl ketone and cyclohexanone, respectively, followed by dehydrochlorination of intermediate 5-chloromethyl derivatives.     

Investigation of homopolymerization rate of perfluoro-4,5-substituted-2-methylene-1,3-dioxolane derivatives and properties of the polymers

Five perfluoro-4,5-substituted-2-methylene-1,3-dioxolane monomers were synthesized. These monomers were found to readily polymerized by a free radical initiator in bulk and/or in solutions. Homopolymerization rates were determined using in situ ¹⁹F NMR measurements and found to be 0.25 to 1.66 × 10⁻⁴ mol L⁻¹ s⁻¹ in 1,1,2-trichlorotrifluoroethane at 41 °C using the perfluorodibenzoyl peroxide as an initiator. The rates depend on the substituents on the 4 and 5 positions of the dioxolane. The purified polymers were thermally stable (up to 350 °C). They show low refractive indexes (1.33-1.36 at 532 nm). They are transparent from UV to near IR region and have high glass transition temperatures (100-170 °C).     

A novel route to poly(α-hydroxyacrylic acid) derivatives by the hydrolysis of polymers containing 1,3-dioxolan-4-one moiety

The alkali hydrolysis of poly(2,2-dimethyl-5-methylene-1,3-dioxolan-4-one) and poly(2,2-dimethyl-5-methylene-1,3-dioxolan-4-one-co-styrene) was carried out with a sodium hydroxide solution (40%) in tetrahydrofuran at room temperature to obtain poly(α-hydroxyacrylic acid) or poly(α-hydroxyacrylic acid-co-styrene) with number-average molecular weights of 39,000–73,000 in 41–86% yields. The styrene unit in the hydrolyzed copolymer hindered the formation of a lactone ring. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1629–1633, 2001     

SYNTHESIS AND POLYMERIZATION OF 2-OXO-3-METHYLENE-1,4-DIOXANES

A new kind of monomers was successfully synthesized by the reaction between 2-chloro methyl cycloketal and trimethylsilyl cyanide, followed by ring closure and dehaiogenation. Polymerizations of the monomers were carried out in benzene solution at 80℃with benzoyl peroxide as initiator. Both the structures of monomers and polymers were characterized by IR, ~1H NMR, ~(13)C NMR and elemental analysis.     

Synthesis and characterization of phosphonate‐containing polysiloxanes

Phosphonate‐functionalized polysiloxanes have been prepared with a new siloxane/phosphonate monomer. The reaction of 3‐chloropropylmethyldimethoxysilane with trimethylphosphite or triethylphosphite produces several new monomers containing pendant phosphonate groups. Copolymerization with dimethyldimethoxysilane has produced polymers soluble in most organic solvents. The acid hydrolysis of the phosphoryl esters has produced hydrophilic siloxane polymers containing phosphonic acid groups. The thermal properties of the polymers and several related small molecules have been compared with thermogravimetric analysis. Both the monomers and the resulting polymers have been characterized with ¹H, ¹³C, ³¹P, and ²⁹Si NMR. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 48–59, 2003     

Polyimides with main-chain photosensitive groups: Synthesis, characterization and their properties as liquid crystal alignment layers

In this work, a series of polyimides containing main-chain chalcone groups and side-chain cinnamate or acetate groups were synthesized. In the synthetic route, three dianhydride monomers were prepared by the reactions of 1,3-dihydro-1,3-dioxoisobenzofuran-5-carbonyl chloride with 1,3-bis(4-hydroxylphenyl)prop-2-en-1-one, 1,3-bis(4-(2-hydroxyethyl)phenyl)prop-2-en-1-one, and 1,3-bis(4-hydroxyphenyl)-pent-1-en-3-one-4-en, respectively. The precursor polyimides were obtained by the polycondensation of the dianhydride monomers with 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and the in situ imidization. After the polymerization, the final products were obtained by introducing the side groups through the reactions of the polyimide precursors with cinnamoyl chloride or acetic anhydride. The chemical structures and properties of the polyimides were characterized by elemental analysis, ¹H NMR, ¹³C NMR, FTIR, GPC, and thermal analysis. The polyimides show high thermal stability and good solubility in aprotic polar organic solvents. The polyimides can undergo sensitive [2+2] photocycloaddition reaction upon the UV light irradiation. After irradiation with linearly polarized UV light, the polyimide thin films can induce 5CB liquid crystal molecules to homogeneously align in the liquid crystal cells. Both the alignment ability and pretilt angles of the molecular orientation depend on the chemical structures of the polyimides.     

Photo and electrically switchable behavior of azobenzene containing pendant bent‐core liquid crystalline polymers

New class of photo and electrically switchable azobenzene containing pendant bent‐core liquid crystalline monomers ( AZBM 1, 2 , and 3 ) and their polymers ( AZBP 1, 2 , and 3 ) are reported. The synthesized precursors, monomers, and polymers were characterized by FT‐IR, ¹H, and ¹³C NMR spectroscopy. Thermal stability of polymers was examined by thermogravimetric analysis and revealed stable up to 260 °C. The mesophase transition of monomers and polymers are observed through polarized optical microscopy (POM) and further confirmed by differential scanning calorimetry (DSC). The electrically switching property of monomers and their polymers were studied by electro‐optical method. Among the three monomers AZBM 1, 2 , and 3 , AZBM 1 and 2 exhibit antiferroelectric (AF) switching and AZBM 3 exhibits ferroelectric (F) switching behavior. On the other hand, low molecular weight polymers ( AZMP 1, 2 , and 3 ) show weak AF and F switching behavior. The photo‐switching properties of bent‐core azo polymers are investigated using UV‐vis spectroscopy, trans to cis isomerization occurs around 25 s for AZBP‐1 and 30 s for AZBP‐2 and 3 in chloroform, whereas reverse processes take place around 80 and 90 s. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Microwave-Assisted Synthesis,and Stereochemical and Biological Aspects of Some Antimony(III) and Bismuth(III) Complexes with Biologically Potent Bidentate Schiff Bases

Tetra- and pentacoordinated antimony and bismuth derivatives have been prepared by the interactions of monophenylantimonydichloride(III), trichlorostibane, and trichlorobismuthane with the sodium salts of 3-(indolin-2-one)hydrazinecarbothioamide (L¹H) and 3-(indolin-2-one)hydrazinecarboxamide (L²H), under microwave irradiation as well as by conventional heating. These compounds were further characterized by analytical and spectroscopic techniques including UV, IR, ¹H NMR, and ¹³C NMR spectra. Newly synthesized complexes with their corresponding ligands were also tested for their antifungal and antibacterial activities.     

Synthesis and Characterization of Photosensitive Phosphorus Based Polymers Containing α,β‐Unsaturated Ketones in the Main Chain

1,3‐Bis(4‐hydroxyphenyl)propenone (BHPP) and 3‐(4‐hydroxy‐3‐methoxy phenyl)‐1‐(4‐hydroxyphenyl)propenone (HMPHPP) were used as monomers for preparing photosensitive phosphorus containing polyesters. The photosensitive monomers BHPP and HMPHPP were prepared respectively by refluxing 4‐hydroxybenzaldehyde and 3‐methoxy‐4‐hydroxybenzaldehyde with 4‐hydroxy acetophenone. The polyesters were synthesized by interfacial polycondensation of photosensitive diols with N‐phenylphosphoramidic dichloride using hexadecyltrimethyl ammonium bromide (HDTMAB) as phase‐transfer catalyst. Copolymers were also prepared by incorporating terephthaloyl chloride in the polymer backbone. The synthesized monomers and polymers were characterized by UV, FT‐IR and ¹H, ¹³C and ³¹P‐NMR spectroscopic techniques. The resulting polymers had inherent viscosities in the range of 0.15–0.51 dL/g and showed good solubility in polar organic solvents. The thermal properties of the polymers were studied by thermogravimetric analysis and differential scanning calorimetry under nitrogen atmosphere. The TGA data revealed that the 10% weight loss occurs at 275–320°C and all the synthesized polymers showed high char residues. DSC studies indicate that these polymers possess T_g in the range of 48 to 64°C. The photosensitive property of the polymers in film and solution state was investigated by ultraviolet spectroscopy. The effect of incorporation of terephthaloyl unit on photocrosslinking and thermal properties of the polymers was also studied.     

Polymerisation of cyclic monomers, 8. Synthesis and radical polymerisation of hybrid 2‐vinylcyclopropanes

Hybrid 2‐vinylcyclopropanes were synthesised by the esterification of 1‐methoxycarbonyl‐2‐vinylcyclopropane‐1‐carboxylic acid with hydroxy group containing (meth)acrylates in the presence of 1,3‐dicyclohexylcarbodiimide (DCC). The structure of the new hybrid monomers was confirmed by elemental analysis, IR, ¹H NMR and ¹³C NMR spectroscopy. The radical polymerisation of the hybrid monomers in bulk with 2,2'‐azoisobutyronitrile (AIBN) results in transparent cross‐linked polymers, whereas solution polymerisation partially results in soluble polymers with pendant 2‐vinylcyclopropyl groups.     

2-Phenyl-4-quinolinone Alkaloids from Casimiroa edulis Llave et Lex (Rutaceae)

 Three new 4-quinolinone alkaloids (5,6-dimethoxy-2-(3-methoxyphenyl)-1H-quinolin-4-one, 5,6-dimethoxy-2-(3,4-dimethoxyphenyl)-1H-quinolin-4-one, 5,6-dimethoxy-2-(2,5,6-trimethoxyphenyl)-1H-quinolin-4-one) were isolated from the leaves of Casimiroa edulis Llave et Lex (Rutaceae) cultivated in Egypt. Their structures were determined by UV/Vis, IR, ¹H and ¹³C NMR, and EI mass spectroscopy. The alkaloids were also detected in the kernels of the seeds.     

Analysis of the structure of 2,5-dimethyl-4-methylene-1, 3-oxathiolane by NMR spectroscopic methods

The ¹H and ¹³C NMR spectra of 2,5-dimethyl-4-methylene-1,3-oxathiolane were analyzed by comparison of the calculated and experimental parameters with the aid of a paramagnetic shift reagent. The data obtained from the NMR spectra were used for the establishment of the structures of the products of isomerization and alcoholysis of 2,5-dimethyl-4-methylene-1,3-oxathiolane.     

Application of cationic polymerization to grafting and coating of silica particles

The cationic polymerization of electron rich monomers such as vinyl ethers, vinyl furane, and cyclopentadiene on silica surfaces can be initiated by aryl methyl halides. The reactions yield always soluble polymers (by heterogeneous catalysis) and novel polymer/silica hybrid materials. The link between polymer and solid is caused by covalent Si-O-C bonds, by network formation of the polymers during the chain growth, or by a combination of both of them. The analysis of the polymer structures on the surface by ¹H MAS NMR spectroscopy in suspension and by solid state ¹³C CP MAS NMR spectroscopy is described. Proof of Si-O-C bonds via DRIFT spectroscopy and ¹³C CP MAS NMR spectroscopy is given. The most effective method of irreversibly linking the polymer to the silica surface is the network formation. Polyvinyl ethers are bound strongly to the surface, as can be shown by FTIR measurements, but the linkage is not stable due to the Si-O-C bonds' susceptibility to hydrolysis. Poly-cyclopentadienes (PCPD) are linked to the surface by Si-O-C bonds, which show an extraordinary high resistance to acids and bases. Si-O-C bond formation of poly-2-vinyl furane could not yet be detected by ¹³C CP MAS NMR spectroscopy and DRIFT spectroscopy. In this case the high degree of coating derives from the bifunctionality of 2-vinyl furane: it may undergo Friedel-Crafts-alkylation at the 5-position of the furane ring as well as chain polymerization via the vinyl group at the 2-position.     

2-Phenyl-4-quinolinone Alkaloids from Casimiroa edulis Llave et Lex (Rutaceae)

Summary.  Three new 4-quinolinone alkaloids (5,6-dimethoxy-2-(3-methoxyphenyl)-1H-quinolin-4-one, 5,6-dimethoxy-2-(3,4-dimethoxyphenyl)-1H-quinolin-4-one, 5,6-dimethoxy-2-(2,5,6-trimethoxyphenyl)-1H-quinolin-4-one) were isolated from the leaves of Casimiroa edulis Llave et Lex (Rutaceae) cultivated in Egypt. Their structures were determined by UV/Vis, IR, ¹H and ¹³C NMR, and EI mass spectroscopy. The alkaloids were also detected in the kernels of the seeds. Received May 28, 2001. Accepted (revised) July 24, 2001     

Extraction of Iridium(IV) by 1-(2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl-methyl)-1H-1,2,4-triazole from Hydrochloric Solutions

Extraction of iridium(IV) by 1-(2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl-methyl)-¹H-1,2,4-triazole from hydrochloric solutions was studied. Optimal extraction parameters were determined. The mechanism of iridium(IV) extraction in this system is ion exchange (3.0 mol/L HCl and τ_cont = 5 min). Electronic, ¹H NMR, ¹³C NMR, and IR spectroscopy and elemental analysis were used to determine the composition of the extracted compound.     

Syntheses,characterizations and properties of boronoalkylalkoxycalix[4]arenes

Some new calixarenes bearing boronic acid moieties, boronoalkylalkoxycalix[4]arenes, were synthesized by allylation, Claisen's rearrangement, alkylation, hydroboration and hydrolysis from 25,26,27,28-tetrahydroxycalix[4]arene and their structures were identified by elemental analysis, IR, ¹H NMR, ¹³C NMR, ¹¹B NMR, MS and UV spectra. The UV data showed that tetraalkoxycalix[4]arene tetraalkyltriboronic acid could coordinate significantly with carbohydrates.