Polymerizability and Chiroptical Properties of the N-Substituted Maleimide Bearing L-Phenylalanine Alkyl Ester

Kagawa, Kensoh; Oishi, Tsutomu

doi:10.1295/polymj.28.1

Cited by 22 publications

(9 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…43,44 Similarly the methine carbons, C ␣ , may appear as a complex multiplet due to stereoregularity effects. 45 As expected for substituted polymaleimides prepared by free radical polymerization, polymers PM n do not show any stereoregularity. The methine protons, H ␣ , give rise to a broad peak from 3 to 4 ppm, which overlaps with the signals assigned to the OCH 2 OO and OCH 2 N͗ protons (Fig.…”

supporting

confidence: 56%

Synthesis and characterization of polymaleimides containing 4-cyanobiphenyl-based side groups for nonlinear optical applications

Gaṅgādhara

Noël

Thomas

et al. 1998

J. Polym. Sci. A Polym. Chem.

View full text Add to dashboard Cite

A new homologous series of SCLCPs containing the 4‐cyanobiphenyl mesogenic group attached to the polymaleimide backbone through paraffinic spacers of two to eight methylene units have been prepared. All the polymers exhibit liquid crystalline behavior; specifically SAd‐ (or SC‐) like and nematic phases are observed. The glass transition temperature decreases from 150 to 43°C on increasing spacer length. The isotropization temperatures exhibit an odd–even effect on varying the length and parity of the spacer, in which the odd members exhibit the higher values. This is attributed to the change in the average shape of the side chain as the parity of spacer is varied. The isotropization temperatures (>300–120°C) and the mesophase thermal stabilities (190–60°C) are high. Comparison is made with polymers containing the same mesogenic group attached to backbones of decreasing rigidity. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2531–2546, 1998

show abstract

supporting

confidence: 56%

Synthesis and characterization of polymaleimides containing 4-cyanobiphenyl-based side groups for nonlinear optical applications

Gaṅgādhara

Noël

Thomas

et al. 1998

J. Polym. Sci. A Polym. Chem.

View full text Add to dashboard Cite

show abstract

“…[20][21][22] In this work the main chain signals of poly((S)-(À)-MVMI)s with higher specific rotations ((A) and (B) in Figure 3) within 40-46 ppm ((A) and (B) in Figure 4, the expanded 13 C NMR spectra) were sharper than that of the polymer obtained from radical polymerization ((D) in Figure 4) and the polymer of lower specific rotation ((C) in Figure 4). This indicates the polymers obtained by asymmetric anionic polymerization with organometal/ligand complex have more stereoregular structures than that obtained by radical polymerization or anionic polymerization with only organometal n-BuLi as initiator.…”

Section: Chiroptical Properties and Structures Of Poly((s)-(à)-mvmi)smentioning

confidence: 99%

“…20 Further from the results, the radical polymerizations of N-maleoyl-L-phenylalanine cyclohexyl ester (CHPAM) and other four types of Nmaleoyl-L-phenylalanine alkyl ester (RPAM) (alkyl: ethyl (EPAM), butyl (BPAM), dodecyl (DPAM), and benzyl (BZPA)) were performed. [21][22][23] It was known from these researches that the bulkiness of ester group decreased polymerizability but was favorable to asymmetric induction in the main chain of the homopolymer. From the above results, the asymmetric anionic polymerizations of chiral RMIs bearing an amino acid residue with interesting initiators like organometal/(S,S)-Bnbox complexes may give polymers of high specific rotation and stereoregular structure, thus the research is in a strong desire.…”

mentioning

confidence: 99%

Asymmetric Anionic Polymerization of (S)-(−)-N-Maleoyl-L-Valine Methyl Ester

Zhang

Onimura

Tsutsumi

et al. 2004

Polym J

Self Cite

View full text Add to dashboard Cite

ABSTRACT:A kind of N-substituted maleimide (RMI), chiral (S)-(À)-N-maleoyl-L-valine methyl ester ((S)-(À)-MVMI) was synthesized successfully from L-valine and maleic anhydride with a specific rotation of ½ 435 ¼ À102:2 . Intensive interest is focused on syntheses of optically active polymers in recent years because of their expected applications to chiral stationary phase of high performance liquid chromatography (HPLC), chiral catalysts and adsorbents.1-11 Asymmetric synthesis polymerization is one of the ways available for synthesizing optically active polymers. In this way, Nsubstituted maleimides were paid great attention because their polymers can be threo-diisotactic structure by trans-opening reaction of a carbon-carbon double bond. As early as in 1982, Okamoto and co-workers reported asymmetric polymerizations of PhMI at the 28th Meeting of Polymer Science (Kobe, Japan). In 1991, they systematically reported asymmetric polymerizations of PhMI with various chiral anionic initiators, the highest specific rotation of ½ 25 D ¼ À23:7 was obtained using a n-BuLi-Sp-CuI complex.2 The research on asymmetric anionic polymerizations of eleven types of achiral RMIs [N-substituent: R = npropyl (PMI), isopropyl (IPMI), n-butyl (nBMI), isobutyl (IBMI), s-butyl (SBMI), t-butyl (TBMI), cyclohexyl (CHMI), benzyl (BZMI), phenyl (PhMI), 1-naphthyl (1-NMI), and 2-fluorenyl (FMI)] with a nBuLi/Sp complex as initiator was also reported by Oishi et al.12 Recently, a new attempt for the anionic polymerizations of achiral RMIs by using chiral bisoxazoline derivatives as chiral ligands were carried out by Oishi et al. Methylene bridged chiral bisoxazoline derivatives were found effective chiral ligands in anionic polymerizations of achiral RMIs. [13][14][15][16][17] Although the polymers of high specific rotations were obtained by asymmetric anionic polymerizations of chiral RMI with organometal and chiral ligand such as Sp or Bnbox,18,19 the reported most chiral RMIs were carried out mainly by radical polymerizations, i.e., N-maleoyl-L-alanine (AMI) and N-maleoyl-Lphenylalanine (PAMI) were radically polymerized in several solvents to obtain optically active polymers, their specific rotations were ½ D ¼ À32to À42 and ½ 25D ¼ À144 to À164 for AMIs and PAMIs, respectively. 20 Further from the results, the radical polymerizations of N-maleoyl-L-phenylalanine cyclohexyl ester (CHPAM) and other four types of Nmaleoyl-L-phenylalanine alkyl ester (RPAM) (alkyl: ethyl (EPAM), butyl (BPAM), dodecyl (DPAM), and benzyl (BZPA)) were performed. [21][22][23] It was known from these researches that the bulkiness of ester group decreased polymerizability but was favorable to asymmetric induction in the main chain of the homopolymer. From the above results, the asymmetric anionic polymerizations of chiral RMIs bearing an amino acid residue with interesting initiators like organometal/(S,S)-Bnbox complexes may give polymers of high specific rotation and stereoregular structure, thus the research is in a strong desire.In this work (S)-(À)-N-maleoyl...

show abstract

“…[1][2][3][4][5][6][7][8] In the past decades, Oishi et al have systematically researched syntheses and asymmetric polymerizations of achiral or chiral N-substituted maleimides (RMIs) and optical resolution ability of poly-(RMI)s. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] Since RMI consists of an 1,2-disubstituted ethylene structure owning characteristic polymerization reactivity, polymerizations of RMI proceed only through trans-addition to form threo-disyndiotactic and threo-diisotactic main chains. 27,28 From the previous view, only threo-diisotactic structure can exhibit optical activity due to the excess of (S,S)-or (R,R)-chiral stereogenic centers in the main chain, and threo-disyndiotactic one shows no optical activity because of the equal amount of (S,S)-and (R,R)-configurations. 14,29 Amino acids are important and useful substances for chiral auxiliaries and building blocks in organic syntheses.…”

mentioning

confidence: 98%

Asymmetric Polymerization of (S)-N-Maleoyl-L-Leucine Allyl Ester and Chiral Recognition Ability of Its Polymer as Chiral Stationary Phase for HPLC

Gao

Isobe

Onimura

et al. 2007

Polym J

Self Cite

View full text Add to dashboard Cite

ABSTRACT:(S)-N-Maleoyl-L-leucine allyl ester ((S)-ALMI), a kind of N-substituted maleimide having two double bonds with different reactivities, was newly synthesized from maleic anhydride, L-leucine, and allyl alcohol. Asymmetric polymerizations were carried out to obtain optically active polymers. Poly((S)-ALMI) obtained by anionic polymerization with n-butyllithium/(S,S)-(1-ethylpropylidene)-bis(4-benzyl-2-oxazoline) (n-BuLi/Bnbox) complex in THF showed the highest negative specific rotation of À429:1. Chemoselective polymerization behaviors of (S)-ALMI on the two reactive groups were elucidated. In anionic polymerizations, only the double bond in the maleimide moiety exclusively took part in the polymerization, affording the corresponding poly((S)-ALMI) with the allyl pendant group. In radical polymerizations, the solvents strongly affect the radical polymerization behaviors of (S)-ALMI. Chiroptical properties and structures of the poly((S)-ALMI)s obtained were investigated by GPC, CD, XRD, and NMR measurements. The methods of preparing chiral stationary phases (CSPs) for high performance liquid chromatography (HPLC) and the chiral recognition ability of the optically active poly((S)-ALMI) were also discussed.

show abstract

Polymerizability and Chiroptical Properties of the N-Substituted Maleimide Bearing L-Phenylalanine Alkyl Ester

Cited by 22 publications

References 19 publications

Synthesis and characterization of polymaleimides containing 4-cyanobiphenyl-based side groups for nonlinear optical applications

Synthesis and characterization of polymaleimides containing 4-cyanobiphenyl-based side groups for nonlinear optical applications

Asymmetric Anionic Polymerization of (S)-(−)-N-Maleoyl-L-Valine Methyl Ester

Asymmetric Polymerization of (S)-N-Maleoyl-L-Leucine Allyl Ester and Chiral Recognition Ability of Its Polymer as Chiral Stationary Phase for HPLC

Contact Info

Product

Resources

About