New monofunctional derivatives of poly(ethylene glycol)s via monotrityl intermediates

Pozzo, Alma Dal; Vigo, Angelo; Donzelli, Giovanni

doi:10.1002/macp.1989.021901012

Cited by 11 publications

(5 citation statements)

References 8 publications

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“…The complete PEO derivatization is thus difficult to obtain, whatever the new function is which reacts with the telechelic hydroxy groups of PEO. [9,10] Furthermore, as mentioned above, reactions were found to proceed quite slowly, especially in mild conditions, while giving a high modification yield. The aim of this work is to optimize a grafting reaction of large groups on PEO chain ends which could be applied to the synthesis of polyrotaxane starting from a pseudopolyrotaxane containing PEO.…”

Section: Introductionmentioning

confidence: 95%

A New Versatile Radical Addition on α, ω‐Dimethacrylate Poly(ethylene oxide)

Jarroux¹,

Guégan²,

Buchmann³

et al. 2004

Macro Chemistry & Physics

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Summary: The synthesis of α,ω‐di(2‐methyl‐6‐pyrenyl‐2‐succinimidylhexanoic ester)poly(ethylene oxide) (Py(S)‐EOn‐(S)Py) was obtained by a new radical reaction between 4‐pyrenylbutanoate N‐hydroxysuccinimidyl ester and α,ω‐dimethacrylate poly(ethylene oxide). The reason for the choice of such bulky groups is a possible application of this reaction to the synthesis of polyrotaxane from polypseudorotaxane. Two reaction media were examined, heterogeneous in water at room temperature using persulfate as initiator, or homogeneous in DMSO at 60 °C using AIBN as initiator. Structural characterization of the functionalization products was carried out by SEC, MALDI TOF, and NMR spectroscopies. It was shown that two types of α,ω‐dipyrenyl PEO could be obtained, one corresponding to the expected product (Py(S)‐EOn‐(S)Py), the other corresponding to the same structure but without the succinimidyl substituent (Py(H)‐EOn‐(H)Py). It was also shown that in the soluble system macrocycles could be formed and this last aspect has been assigned to intramolecular interactions existing between the pyrenyl groups. An interesting aspect of this synthesis is the possibility to find conditions giving high yields without crosslinking and fairly reduced amount of coupling. magnified image

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Section: Introductionmentioning

confidence: 95%

A New Versatile Radical Addition on α, ω‐Dimethacrylate Poly(ethylene oxide)

Jarroux¹,

Guégan²,

Buchmann³

et al. 2004

Macro Chemistry & Physics

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“…The synthetic strategy is based on the H 2 SO 4 -catalyzed hydrolysis of propargylated and PEGylated cyanohydrin derivatives prepared from efficient coupling of monotritylated OEGs, propargyl alcohol, and 2 . As shown in Scheme , OEGs 6b – e were desymmetrized and monoprotected with trityl chloride to afford a mixture of monotritylated OEGs 7b – e and ditritylated OEGs as white solids ( 7b and 7c ) or pale red viscous liquids ( 7d and 7e ) in high yields (>92%) without further purification. , Byproducts ditritylated OEGs in 7b – e were not removed, and they or their derivatives were carried over until final purification of 1b – e , since it was anticipated that they could be easily removed in their derivatized forms (OEG dipropargyl ethers) while purifying final α-hydroxy acids 1b – e .…”

Section: Results and Discussionmentioning

confidence: 99%

“…Synthesis of Propargyloxy Lactic Acid (1a) shown in Scheme 3, OEGs 6b−e were desymmetrized and monoprotected with trityl chloride to afford a mixture of monotritylated OEGs 7b−e and ditritylated OEGs as white solids (7b and 7c) or pale red viscous liquids (7d and 7e) in high yields (>92%) without further purification. 49,50 Byproducts ditritylated OEGs in 7b−e were not removed, and they or their derivatives were carried over until final purification of 1b−e, since it was anticipated that they could be easily removed in their derivatized forms (OEG dipropargyl ethers) while purifying final α-hydroxy acids 1b−e. Direct incorporation of a propargyl group to 7b−e is not plausible due to the fact that deprotection of the trityl group will employ a Pd-catalyzed hydrogenolysis and due to possible side reactions of terminal alkyne when excess NaH is used in subsequent steps.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Synthesis of a Library of Propargylated and PEGylated α-Hydroxy Acids Toward “Clickable” Polylactides via Hydrolysis of Cyanohydrin Derivatives

2014

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A new simple and practical protocol for scalable synthesis of a novel library of propargylated and PEGylated α-hydroxy acids toward the preparation of “clickable” polylactides was described. The overall synthesis starting from readily available propargyl alcohol, bromoacetaldehyde diethyl acetal, and OEGs or PEGs was developed as a convenient procedure with low cost and no need of column chromatographic purification. The terminal alkyne functionality survives from hydrolysis of the corresponding easily accessible cyanohydrin derivatives in methanolic sulfuric acid. Facile desymmetrization, monofunctionalization, and efficient chain-elongation coupling of OEGs further enable the incorporation of OEGs to α-hydroxy acids in a simple and efficient manner. At the end, synthesis of allyloxy lactic acid indicates that an alkene group is also compatible with the developed method.

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“…The tritylation reaction was selected for the synthesis of monofunctional derivatives of monodispersed oligo(ethyleneglycol)s with degrees of oligomerization of 3 and 4 28. Indeed, the more straightforward direct tosylation of oligo(ethyleneglycol) could give rise to a mixture of monosubstituted and disubstituted derivatives.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and polymerization of amphiphilic methacrylates containing permanent dipole azobenzene chromophores

Altomare

Ciardelli

Gallot

et al. 2001

J. Polym. Sci. A Polym. Chem.

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New amphiphilic photochromic methacrylates with the structures of 4- [methacryloyloxyoligo(ethyleneglycol)]-4Ј-cyanoazobenzene (MEn) and 4-methacryloyloxy-4Ј-{2-cyano-3-oxy-3-[-methoxyoligo(ethyleneglycol)]prop-1-en-1-yl}azobenzene (MEnMe) and oligo(oxyethylene) segments of different lengths were synthesized. These methacrylates were characterized by the presence of permanent dipole azobenzene chromophores and hydrophilic oligo (oxyethylene) segments. The methacrylates were obtained with six-step and five-step synthetic sequences, respectively, in 12-47% overall yields. The radical polymerization of the MEn monomers afforded a 50% yield of the corresponding polymers as orange solids with a number-average molecular weight of about 40 kD. No solid polymer was obtained from the radical polymerization of the MEnME compounds. Two-dimensional NMR spectra allowed the unequivocal assignment of the NMR signals and demonstrated a significant contribution of internal charge transfer to the electronic distribution of the azobenzene chromophore. Relaxation time measurements confirmed that the flexible polyether segment effectively decoupled photochromic groups from the polymer backbone. Optical microscopy, differential scanning calorimetry analysis, and X-ray diffraction data demonstrated the presence of interdigitated smectic mesophases. The stability of mesophases showed a significant dependence on the chemical structure of the analyzed compounds. The glass-transition temperatures of the polymers were rather low because of the plasticizing effect of the spacers. The monomers and polymers were used for the deposition of Langmuir films and Langmuir-Blodgett-Kuhn multilayers. A strong influence of the macromolecular structure on the film properties was observed. The photoresponsive properties of monomers and polymers were investigated with irradiation at different wavelengths. Isomerization kinetics were independent of both molecular weight and spacer length.

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New monofunctional derivatives of poly(ethylene glycol)s via monotrityl intermediates

Cited by 11 publications

References 8 publications

A New Versatile Radical Addition on α, ω‐Dimethacrylate Poly(ethylene oxide)

A New Versatile Radical Addition on α, ω‐Dimethacrylate Poly(ethylene oxide)

Synthesis of a Library of Propargylated and PEGylated α-Hydroxy Acids Toward “Clickable” Polylactides via Hydrolysis of Cyanohydrin Derivatives

Synthesis and polymerization of amphiphilic methacrylates containing permanent dipole azobenzene chromophores

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