Mild Synthesis of Amino‐Poly(ethylene glycol)s. Application to Steric Stabilization of Clays

Mongondry, Philippe; Bonnans-Plaisance, C.; Jean, Martine; Tassin, Jean-François

doi:10.1002/marc.200350012

Cited by 41 publications

(46 citation statements)

References 23 publications

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“…As already mentioned, BE-CNC and CNC were TEMPO-oxidised before the grafting. PEG-NH 2 was here synthesized according to a previously reported method (Mongondry et al 2003). The target for the amount of grafted PEG on the cellulosic elements was around 35 wt% (relative to the mass of cellulose), see also later in the text.…”

Section: Be-cncmentioning

confidence: 99%

Rheological properties of nanocellulose suspensions: effects of fibril/particle dimensions and surface characteristics

et al. 2017

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The rheological properties of aqueous suspensions based on three different nanocelluloses were compared. One system was obtained via acid hydrolysis (thus yielding crystalline nanocellulose, CNC) and the other two from mechanical shearing, but from different origins and subjected to different pretreatments. Of the latter two, one was considered to be a rather typical cellulose nanofibril (CNF) suspension whereas the other was a kind of intermediate between CNF and CNC. All three nanocellulose elements differed in dimensions as evident from transmission electron microscopy and atomic force microscopy. With regard to the length of the fibrils/particles, the three nanocelluloses formed three distinct groups with lengths between 200 and slightly more than 800 nm. The three cellulosic elements were also subjected to a TEMPO-mediated oxidation yielding a similar carboxylate content in the three systems. Furthermore, the TEMPO-oxidized elements were grafted with poly(ethylene glycol) (PEG). The amount of grafted PEG was about 35 wt%. The shear viscosity, the storage modulus and the loss modulus of suspensions of the unmodified, the TEMPO-oxidized and the grafted nanocelluloses were determined at room temperature and the solids content of the suspensions was varied between 0.7 and 2.0 wt%. It was concluded that the rheological properties varied significantly between the suspensions depending on the dimensions of the cellulosic elements and their surface characteristics. In this context, the length (or the aspect ratio) of the particles played a very important role.

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Section: Be-cncmentioning

confidence: 99%

Rheological properties of nanocellulose suspensions: effects of fibril/particle dimensions and surface characteristics

et al. 2017

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“…2 was prepared [12] by the deglycosylation of 1, and 3 was prepared from the appropriate monomethoxy-amino-PEG by the reaction with thiophosgene [16]. Specific optical rotations were measured with a Perkin-Elmer 341 automatic polarimeter.…”

Section: Methodsmentioning

confidence: 99%

“…To a solution of 2 (0.085 mmol) in DMSO (2.0 ml) 3 (0.085 mmol) [16] was added and the homogeneous reaction mixture was kept at room temperature for 48 hours. The product 4 was precipitated with dry ether, filtered off, washed with a small volume of ether and the crude product (170 mg) was purified by column chromatography (A) to obtain 30.6% of pure 4.…”

Section: N-methoxy-peg-yl-thioureido Aglyco-ristocetin (4)mentioning

confidence: 99%

N-Glycosylthioureido Aglyco-ristocetins without Platelet Aggregation Activity

et al. 2007

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The water-soluble N-methoxy-PEG-yl-, N-b-Dglucopyranosyl-and N-b -D-maltosylthioureido aglycoristocetin were prepared which, in contrast to ristocetin A, did not induce thrombocyte aggregation. The antibacterial activity of N-b -D-maltosylthioureido aglyco-ristocetin A against MRSA was comparable to that of ristocetin A, while its activity against Enterococcus faecalis (VRE, TSE) is somewhat stronger when compared to those of vancomycin and ristocetin A.

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“…The product was purified by column chromatography on silica gel using an 85: 15 Compound 10 6 (0.196 g, 0.13 mmol) was dissolved in dry CH 2 Cl 2 (50 ml) and 2 (0.118 g, 0.37 mmol) was added, and the reaction mixture was stirred for 3 days at room temperature. The product was purified by column chromatography on silica gel using a 85:15 CH 2 Cl 2 -MeOH solvent system as eluent.…”

Section: Ms (Maldi-tofmentioning

confidence: 99%

“…Monomethoxy-PEG (MW average ¼1132 Da) and PEG (MW average ¼ 1382 Da) were converted 15 into the monoamino (3) and diamino (4) derivatives, whose treatment with thiophosgene gave the corresponding mono-and diisothiocyanates 5 and 6, respectively (Scheme 1).The reaction of 4 and 6 with ciprofloxacin and norfloxacin under mild conditions (Scheme 1) led to the PEG-conjugates (7,8,9,10), whose structures were proved by matrix-assisted laser desorption/ ionization (MALDI) mass spectrometry and NMR spectroscopy. (Figure 1 represents the MALDI-time of flight (TOF) mass spectrum of 6 and 9).…”

mentioning

confidence: 99%

Synthesis and antimicrobial activity of ciprofloxacin and norfloxacin permanently bonded to polyethylene glycol by a thiourea linker

et al. 2009

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C 2 -symmetric (divalent) biologically active molecules are an extensively studied field, as certain substances possessing a B-linker-B type structure (where B represents a bioactive molecule) have promising biological properties. 1 The synthesis and investigation of the dimers of the highly antibacterial quinolonecarboxylic acids were also carried out. However, the norfloxacin dimers linked with an alkyl chain, described by Coppel et al., 2 were very slightly active. Later Kerns et al. 3-5 synthesized the C 2 -symmetric and mixed dimers of ciprofloxacin and norfloxacin using 1,4-phenylenebis-methylene and 2-butene-1,4-diyl linkers. These derivatives possessed comparable activity with that of the monomers and, in a few cases, higher MIC values were found against certain drug-resistant strains.Polyethylene glycol (PEG), a cheap and nontoxic telechelic polymer diol of amphiphilic character is soluble both in water and organic solvents; therefore, it is often used as a carrier for drug molecules.Bioactive molecules linked covalently to PEG possess favorable pharmacodynamic properties due to high water solubility and lipophilicity of the polymer, and PEGylation usually results in an enhanced biological stability and the products are less immunogenic. The PEGylated drug conjugates are primarily used in a 'releasable' form (that is, in a form linked by means of bondings unstable in a biological milieu).In contrast, in the permanently bonded form, the drug molecule is attached to the polymer with covalent bondings stable in a biological milieu. The permanently bonded form is also advantageous, as numerous drug molecules introduced to therapy contains PEG in such a linkage. Related compounds are the PEGylated derivative of the bovine adenosyl deaminase enzyme ADAGEN, 6 the PEGylated L-asparagine-containing ONCASPAR, 7 PEG-INTRON, 8 which contains PEGylated interferon, and NEULASTA 9 carrying a PEGylated granulocyte-colony stimulating factor. Incorporation of the monofunctional PEG chain(s) to these protein-type bioactive molecules resulted in decreasing immunogenity of the parent compound, as well as in the increase of the circulation half-life time and the stability. There are few reports on permanently bonded drugs, but those compounds exhibit low biological activity. 10 Ciprofloxacin was encapsulated in PEG-coated, long-circulating sustained-release liposomes. 11,12 It is to be noted that Carraher et al. 13 reported the synthesis and biological activity of ciprofloxacin covalently bonded to organotin polymers of 1 and 2. Norfloxacin was also attached to methacrylate polymers. 14 The goal of this work was to investigate the antimicrobial effect of the quinolonecarboxylic acid dimers prepared with a PEG linker, and to study the effect of PEGylation on the antibacterial activity.To investigate the separate effect of the PEGylation and dimerization of 1 and 2 on the antimicrobial effect, both the mono-and bifunctional PEG derivatives of the antimicrobial agents were prepared.Monomethoxy-PEG (MW average ¼1132 Da) and PEG ...

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Mild Synthesis of Amino‐Poly(ethylene glycol)s. Application to Steric Stabilization of Clays

Cited by 41 publications

References 23 publications

Rheological properties of nanocellulose suspensions: effects of fibril/particle dimensions and surface characteristics

Rheological properties of nanocellulose suspensions: effects of fibril/particle dimensions and surface characteristics

N-Glycosylthioureido Aglyco-ristocetins without Platelet Aggregation Activity

Synthesis and antimicrobial activity of ciprofloxacin and norfloxacin permanently bonded to polyethylene glycol by a thiourea linker

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