Chemical modification of poly(1‐chloro‐2‐epoxypropane) using phase transfer catalysis

Nishikubo, Tadatomi; Iizawa, Takashi; Mizutani, Yasushi; Okawara, Masafumi

doi:10.1002/marc.1982.030030907

Cited by 26 publications

(8 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The M̄ w values obtained indicate that the polymeric main chain degraded quite considerably during the reaction. Several papers ,− have reported that this process is an important side reaction when PECH is chemically modified through nucleophilic substitution reactions. On the other hand, although at first sight it may seem meaningless to compare viscosity values because the hydrodynamic volumes of the polymers should be considerably different, the viscosity values of all the modified polymers were much lower than virgin PECH, which suggests that the cleavage side reaction takes place.…”

Section: Resultsmentioning

confidence: 99%

Vinyl-Terminated Side-Chain Liquid-Crystalline Poly(epichlorohydrin) Derivatives Containing Biphenyl and Naphthalene Mesogenic Moieties

Callau¹,

Reina²,

Mantecón³

et al. 1999

Macromolecules

View full text Add to dashboard Cite

Poly(epichlorohydrin) (PECH) was modified to a considerable extent with mesogenic acids, namely 4′-(ω-alkenoxy)-4-biphenylcarboxylic acids and 6-(ω-alkenoxy)-2-naphthalenecarboxylic acids, which leads to side chain liquid crystalline polymers which can be cross-linked through their terminal double bonds in a further step. Cleavage and cross-linking side reactions, which have been reported elsewhere, were observed. The polymers were characterized by NMR, IR, SEC-MALLS, viscosimetry, elemental analysis, DSC, and TGA. The thermal stability of the modified polymers was higher than that of the starting PECH. The mesophases were identified by DSC, light-polarized optical microscopy, and X-ray diffraction. The biphenyl derivatives show smectic A mesophases consisting of a bilayer or partial bilayer structure, which is modulated for the 4′-(5-hexenoxy)-4-biphenylcarboxylic acid derivatives (S A ˜). The 6-(5-hexenoxy)-2-naphthalenecarboxylic acid and the 6-(10-undecenoxy)-2-naphthalenecarboxylic acid derivatives show nematic and smectic C mesophases, respectively.

show abstract

Section: Resultsmentioning

confidence: 99%

Vinyl-Terminated Side-Chain Liquid-Crystalline Poly(epichlorohydrin) Derivatives Containing Biphenyl and Naphthalene Mesogenic Moieties

Callau¹,

Reina²,

Mantecón³

et al. 1999

Macromolecules

View full text Add to dashboard Cite

show abstract

“…This elimination process had already been observed by Nishikubo et al [10] using IR spectroscopy, but in the present work it has been quantified by 13 C NMR spectroscopy [14]. Figure 1 shows the 13 C NMR spectrum of one of these polymers.…”

Section: Resultsmentioning

confidence: 57%

“…Nishikubo et al [10] reported the chemical modification of PECH with potassium phenolate under phase-transfer conditions, leading to polymers with a low degree of modification, none of which were higher than 23%. In our research group [5,6], we have studied the modification of PECH with carboxylates as nucleophiles and achieved very high degrees of substitution, some of which were close to complete modification.…”

Section: Resultsmentioning

confidence: 98%

Chemical modification of poly(epichlorohydrin) with phenolate. Studies of the side reactions

et al. 1998

View full text Add to dashboard Cite

“…However, with high‐molecular‐weight PECH the polymeric main chain was considerably degraded. This process is reported to be an important side reaction when PECH is chemically modified through nucleophilic substitution reactions,19 but the weight‐average molecular weight ( M w ) values obtained indicate that no strong degradation takes place with low‐molecular‐weight PECH. Therefore, we synthesized low‐molecular‐weight PECH by cationic polymerization with triphenylcarbenium hexafluorophosphate as a catalyst.…”

Section: Resultsmentioning

confidence: 99%

The pH Effect on the Naphthoquinone‐Photosensitized Oxidation of 5‐Methylcytosine

Yamada¹,

Tanabe²,

Itô³

et al. 2008

Chemistry A European J

View full text Add to dashboard Cite

The pH effect on the one-electron photooxidation of 5-methyl-2'-deoxycytidine (d(m)C) by sensitization with 2-methyl-1,4-naphthoquinone (NQ) was investigated. Photoirradiation of an aqueous solution containing d(m)C and NQ under slightly acidic conditions of pH 5.0 efficiently produced 5-formyl-2'-deoxycytidine, whereas similar NQ-photosensitized oxidation of d(m)C proceeded to a lesser extent under more acidic or basic conditions. Fluorescence-quenching experiments revealed that the less-efficient photooxidation at pH values below 4.5 is attributed to the decreased rate of one-electron oxidation of d(m)C owing to protonation at the N(3)-position. The NQ-photosensitized oxidation of an N(4)-dimethyl-substituted d(m)C derivative under various pH conditions also suggests that the pH change in the range of 5.0 to 8.0 may be responsible for a reversible deprotonation-protonation equilibrium at the N(4)-exocyclic amino group of the d(m)C radical cation. In accord with the photochemical reactivity of monomeric d(m)C, the 5-methylcytosine residue in oligodeoxynucleotides was oxidized efficiently by photoexcited NQ-tethered oligodeoxynucleotides under slightly acidic conditions to form an alkali-labile 5-formylcytosine residue.

show abstract

Chemical modification of poly(1‐chloro‐2‐epoxypropane) using phase transfer catalysis

Cited by 26 publications

References 6 publications

Vinyl-Terminated Side-Chain Liquid-Crystalline Poly(epichlorohydrin) Derivatives Containing Biphenyl and Naphthalene Mesogenic Moieties

Vinyl-Terminated Side-Chain Liquid-Crystalline Poly(epichlorohydrin) Derivatives Containing Biphenyl and Naphthalene Mesogenic Moieties

Chemical modification of poly(epichlorohydrin) with phenolate. Studies of the side reactions

The pH Effect on the Naphthoquinone‐Photosensitized Oxidation of 5‐Methylcytosine

Contact Info

Product

Resources

About