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  • Physics  (13)
  • anionic polymerization  (3)
  • chiral stationary phases  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Stereospecific polymerization of benzyl α-(alkoxymethyl) acrylates (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 721-726 
    Details
    ISSN: 0887-624X
    Keywords: benzyl α-(alkoxymethyl)acrylate ; stereospecific polymerization ; anionic polymerization ; isotactic polymer ; tacticity ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α-(Alkoxymethyl) acrylates, such as methyl α-(phenoxymethyl) acrylate, benzyl α-(methoxymethyl)acrylate (BMMA), benzyl α-(benzyloxymethyl)acrylate, and benzyl α-(tert-butoxymethyl)acrylate, were synthesized, and their polymerizability and the stereoregularity of the polymers obtained by radical and anionic methods were investigated. The radically obtained polymers were found to be atactic by 13C- and 1H-NMR analyses, but the polymers obtained with lithium reagents in toluene at -78°C were highly isotactic. Further, it is noteworthy that isotactic polymers were also produced with lithium reagents even in tetrahydrofuran. Effects of polymerization temperature and counter cation on stereoregularity were clearly observed in the polymerization of BMMA, and a potassium reagent afforded an almost atactic polymer. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35:721-726, 1997
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Asymmetric anionic polymerization of (2-fluorophenyl)(4-fluorophenyl)(2-pyridyl)methyl methacrylate leading to a helical polymer (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2013-2019 
    Details
    ISSN: 0887-624X
    Keywords: asymmetric polymerization ; anionic polymerization ; (2-fluorophenyl)(4-fluorophenyl)(2-pyridyl) methyl methacrylate ; optically active polymer ; helix ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel racemic methacrylate, (2-fluorophenyl)(4-fluorophenyl)(2-pyridyl)-methyl methacrylate1 (2F4F2PyMA), was synthesized and polymerized with chiral complexes of N,N′-diphenylethylenediamine monolithium amide (DPEDA-Li) with (-)-sparteine (Sp), (2S, 3S)-(+)-2,3-dimethoxy-1,4-bis(dimethylamino)butane (DDB), and (S)-(+)-1-(2-pyrrolidinylmethyl)pyrrolidine (PMP) in toluene at -78°C. The monomer showed higher resistance against methanolysis compared with triphenylmethyl methacrylate (TrMA) and several other analogues. In the asymmetric anionic polymerization of 2F4F2PyMA, PMP was found to be a more effective chiral ligand than DDB and Sp and gave quantitatively an optically active polymer with nearly perfect isotacticity. Enantiomer selection was observed in the polymerization of racemic 2F4F2PyMA with the chiral lithium complexes. Chiral recognition ability of the optically active poly(2F4F2PyMA) was examined by an enantioselective adsorption experiment. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2013-2019, 1998
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Helix-sense-selective polymerization of phenyl[bis(2-pyridyl)]methyl methacrylate and chiral recognition ability of the polymer (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 2721-2728 
    Details
    ISSN: 0887-624X
    Keywords: phenyl[bis(2-pyridyl)]methyl methacrylate ; optically active polymer ; solvolysis ; chiral stationary phase ; anionic polymerization ; (S)-(+)-1-(2-pyrrolidinylmethyl)pyrrolidine ; optical resolution ; high performance liquid chromatography ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel monomer, phenyl[bis(2-pyridyl)]methyl methacrylate (PB2PyMA), was synthesized. The solvolysis rate of PB2PyMA measured in CDCl3-CD3 OD [1/1 (v/v)] by 1H-NMR spectroscopy at 35°C was much smaller than those of triphenylmethyl methacrylate (TrMA) and diphenyl-2-pyridylmethyl methacrylate (D2PyMA). PB2PyMA was anionically polymerized with the complexes of organolithiums with (-)-sparteine (Sp), (S,S)-(+)-and (R,R)-(-)-2,3-dimethoxy-1,4-bis(dimethylamino)butanes[(+)-and (-) -DDB], and (S)-(+)-1-(2-pyrrolidinylmethyl) pyrrolidine (PMP) in toluene at low temperature. The polymers obtained with Sp and DDB complexes showed low optical activity. PMP complexes, particularly that with N,N′-diphenylethylenediamine monolithium amide, were effective in synthesizing a polymer of high optical rotation ([α]25365 ∼ +1350°) which was comparable to those of poly(TrMA) and poly(D2PyMA) with one-handed helical structure. The optical rotation of poly(PB2PyMA) in a mixture of CHCl3 and 2,2,2-trifluoroethanol (9/1, v/v) slowly decreased with time. Optically active poly(PB2PyMA) coated on macroporous silica gel was able to resolve racemic compounds as a chiral stationary phase for high-performance liquid chromatography. © 1993 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080311107
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  • 4
    Electronic Resource
    Electronic Resource
    Optical resolution of β-lactams on 1-phenylethylcarbamates of cellulose and amylose (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 122-124 
    Details
    ISSN: 0899-0042
    Keywords: 4-acetoxy-2-azetidinone ; antibiotics ; carbapenem ; HPLC ; chiral stationary phases ; cellulose tris(1-phenylethylcarbamate) ; amylose tris(1-phenylethylcarbamate) ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optical resolution of six β-lactams was examined by HPLC using chiral stationary phases consisting of tris((R)-, (RS)-, and (S)-1-phenylethylcarbamate)s of cellulose and amylose. All β-lactams were optically resolved at least by one of the carbamates. Amylose tris((S)-1-phenylethylcarbamate) showed high optical resolving abilities for some β-lactams.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530040210
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  • 5
    Electronic Resource
    Electronic Resource
    Optical resolution of β-lactams by chiral HPLC on tris(phenylcarbamate)s of cellulose and amylose (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 1 (1989), S. 216-222 
    Details
    ISSN: 0899-0042
    Keywords: 4-acetoxy-2-azetidinone ; antibiotics ; carbapenem ; chiral stationary phases ; cellulose tris(phenylcarbamate) ; amylose tris(3,5-dimethylphenylcarbamate) ; CD spectra ; absolute configuration ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Separation and optical resolution of 6 diastereomers and 25 racemates of β-lactams were examined by HPLC on chiral stationary phases composed of six cellulose and one amylose tris(phenylcarbamate) derivatives. Most β-lactams were optically resolved at least by one of the derivatives. The absolute configuration of β-lactams was estimated by CD spectroscopy.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530010307
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  • 6
    Electronic Resource
    Electronic Resource
    Poly(β-Amino acids). V. Synthesis and conformation of oligomeric α-isobutyl-L-aspartate (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 17 (1979), S. 1911-1921 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: α-Isobutyl-L-aspartate oligomers, Z-(α-i-Bu-Asp)2n-OEt (n = 1-5), where Z = benzyloxycarbonyl and OEt = ethyl ester, were prepared stepwise, and their conformation in solution was investigated by optical rotation, circular dichroism (CD), and NMR spectroscopy. The oligomers up to hexamer existed only in a disordered form. An ordered structure began to appear at octamer and decamer in chloroform and 2,2,2-trifluoroethanol. The ordered structure was more favorable for N-unprotected oligomers, H-(α-i-Bu-Asp)2n-OEt, in comparison with the corresponding Z-(α-i-Bu-Asp)2n-OEt. The effects of oligomer concentration and temperature on the structure were slightly observed. The most likely ordered structure was a β form caused by intramolecular association.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1979.170170703
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  • 7
    Electronic Resource
    Electronic Resource
    Anionic copolymerization of optically active α-methylbenzyl methacrylate and trityl methacrylate. I. Reactivity of monomers (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 17 (1979), S. 2917-2928 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The monomer reactivity ratios were determined in the anionic copolymerization of (S)- or (RS)-α-methylbenzyl methacrylate (MBMA) and trityl methacrylate (TrMA) with butyllithium at -78°C, and the stereoregularity of the yielded copolymer was investigated. In the copolymerization of (S)-MBMA (M1) and TrMA (M2) in toluene the monomer reactivity ratios were r1 = 8.55 and r2 = 0.005. On the other hand, those in the copolymerization of (RS)-MBMA with TrMA were r1 = 4.30 and r2 = 0.03. The copolymer of (S)-MBMA and TrMA prepared in toluene was a mixture of two types of copolymer: one consisted mainly of the (S)-MBMA unit and was highly isotactic and the other contained both monomers copiously. The same monomer reactivity ratios, r1 = 0.39 and r2 = 0.33, were obtained in the copolymerizations of the (S)-MBMA-TrMA and (RS)-MBMA-TrMA systems in tetrahydrofuran (THF). The microstructures of poly[(S)-MBMA-co-TrMA] and poly-[(RS)-MBMA-co-TrMA] produced in THF were similar where the isotacticity increased with an increase in the content of the TrMA unit.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1979.170170927
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  • 8
    Electronic Resource
    Electronic Resource
    Anionic polymerization and copolymerization of S-methyl thiomethacrylate (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 17 (1979), S. 3705-3712 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: S-Methyl thiomethacrylate (methyl thiolmethacrylate, MTMA) was polymerized with a variety of anionic initiators such as n-BuLi, octylpotassium, PhMgBr, and Et2AlNPh2 in toluene and THF. Stereoregularity of the polymer (PMTMA) was determined from the 1H-NMR spectrum of poly(methyl methacrylate), which had been derived from PMTMA, because the α-methyl resonance in the 1H-NMR spectrum of PMTMA was not satisfactorily solved owing to the overlap of pentad signals. The 13C-NMR spectrum of PMTMA also showed the splitting due to pentad sequences. Stereoregularity of PMTMA was always low compared with that of poly(methyl methacrylate), which was prepared under the same reaction conditions. MTMA was much more reactive than methyl methacrylate and methacrylonitrile in the copolymerization with n-BuLi in toluene and in THF at -78°C. The lower stereoregulation of the polymerization of MTMA and the higher reactivity of MTMA were mainly ascribed to the higher resonance effect of MTMA.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1979.170171126
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  • 9
    Electronic Resource
    Electronic Resource
    Asymmetric selective polymerization of racemic 1,2-diphenylethyl methacrylate with the ethylmagnesium bromide-(-)-sparteine complex (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1831-1837 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Asymmetric selective (or stereoelective) polymerization of racemic 1,2-diphenylethyl methacrylate (DPEMA) with ethylmagnesium bromide (EtMgBr)-(-)-sparteine catalyst was studied in toluene at -78°C. In the polymerization (S) enantiomer was consumed preferentially and the enantiomeric excess of initially polymerized (S) enantiomer was consumed preferentially and the enantiomeric excess of initially polymerized DPEMA was greater than 90%. Optically pure (R) monomer was recovered at about 70% polymer yield. Poly(DPEMA) obtained with EtMgBr-(-)-sparteine complex was highly isotactic. It was found in the polymerization of optically active DPEMA that optical rotation of poly(DPEMA) was dependent on the tacticity and that isotactic and syndiotactic poly(DPEMA)s showed opposite optical rotations. Circular dichroism spectra of the optically active polymers were measured.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.170220805
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  • 10
    Electronic Resource
    Electronic Resource
    Asymmetric polymerization of triphenylmethyl methacrylate by optically active anionic catalysts (1980)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 3043-3051 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Triphenylmethyl methacrylate (TrMA) was polymerized with two types of asymmetric anionic catalyst, lithium (R)-N-(1-phenylethyl)anilide (LiAn) and (-)-sparteine-butyllithium complex (Sp-BuLi), at -78°C. Both catalysts yielded optically active polymers. The polymers obtained with LiAn in toluene and tetrahydrofuran (THF) showed specific rotations [α]20D of from -50° to -90° (in THF). The [α]20D of the polymer obtained with Sp-BuLi in toluene was positive and increased with polymer yield reaching above +300°s, whereas the polymer obtained in THF showed a low [α]20D (ca. +7°). Gel permeation chromatograms of both polymers obtained with LiAn and Sp-BuLi in THF exhibited rather narrow molecular weight distributions, whereas those obtained in toluene showed at least two or three components with markedly different molecular weights. The circular dichroism (CD) spectrum of the polymer obtained with Sp-BuLi showed strong positive peaks at 208 and 232 nm and a weak band at 250-280 nm; the polymer produced with LiAn showed a similar spectrum with opposite sign. The poly(methyl methacrylate)s derived from these poly(TrMA)s were highly isotactic but showed negligible rotations ([α]20D ± 2° in toluene). The polymer of high molecular weight showed clear polarization under a polarizing microscope and the low polymer obtained with LiAn appeared to show flow birefringence in chloroform at room temperature.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1980.170181013
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