2-Vinylpyridine-l-oxide

Since the applied poly(vinylpyridine)s are only soluble in form of their salts in acidic solution and, therefore, precipitate in the organism of the animal after injection, the application of the corresponding N-oxides, like poly(2-vinylpyridine-l-oxide) PVNO [2] constitutes a decisive improvement (19). 

The uptake of poly-2-vinylpyridine-l-oxide into ly-sosomes of alveolar macrophages of rats (Grund-MANN 1967) mi guinea pigs (Beck and Boje 1967) and hepatic Kupffer cells of mice (Bairati and Castano 1968) has been documented. 

Nash et al. (1966) synthesised another compound, polyvinylpyridinioacetic acid, which has even greater hydrogen bonding capacity than poly-2-vinylpyridine-l-oxide and very efficiently protects macrophages from silica toxicity. This protection was confirmed by Sakabe and Koshi (1967), who also showed that it prevents the increase in acid phosphatase in macrophages following exposure to quartz particles < 2 pm in diameter. However, polybetaine was slightly more active than poly-2-vinylpyridine-1 - oxide. 

The protective effects of syndiotactic and isotactic poly-2-vinylpyridine-l-oxide remarkably differ in the spatial arrangement of the structural units (Holt et al. 1970). The isotactic polymer has probably a helical conformation. When the cultures... 

Fig. 123. Alveolar macrophage from a female rat (breeder Winkelmann, Borchen-Kirchborchen) which inhaled micronized poly-2-vinylpyridine-l-oxide for 15 min per day, 5 times per week from July 25, 1967 to January 15, 1968. Fixed on January 15,1968 under methitural anaesthesia by intratracheal instillation of 2.5 % glutaraldehyde in phosphate buffer (pH 7.4) before opening the thorax. Postfixation with 1 % osmium tetrox-ide in phosphate buffer (pH 7.4). Contrasted en bloc for 12 h with 0.5 % uranyl acetate in 70 % ethanol. Embedded in a 2 8 mixture of methyl and butyl methacrylate. Sectioned at 50 nm. Lead ettrate after Reynolds (1963). Plate 47/07...

Second virial coefficient of poly(2-vinylpyridine-l-oxide)... 

PHMPA = poly(N,N-dimethyl-N N N"N"-tetramethylenephosphoric triamide), PM A A = poly-(methacrylic acid), PVPo = poly(N-vinyl-2-pyrrolidone), P2VP = poly(2-vinylpyridine), PEO = polyethylene oxide), PEI = poly(ethylenimine), PA Am = poly (acrylamide), PVA = poly (vinyl alcohol), PAA = poly(acrylic acid), PGA = poly(L-glutamic acid), P4VP = poly(4-vinylpyridine)... 

In Chapter 3, Lyudmila M. Bronstein, Valentina G. Matveeva and Esther M. Sulman review metal NP catalysis usingpdymers, in particular, work in Bronstein s group concerning the hydrogenation of drain acetylene alcohols and direct oxidation of L-sorbose. These authors stress the importance of and interest in block copolymers such as pdystyrene-hlock-poly-4-vinylpyridine, PS-b-4VP, and even better poly (ethylene oxide)-block-poly-2-vinylpyridine, PEO-h-P4VP (the latter being used in water). The catalytic efficiency is optimal for the smallest NPs and decrease as the NP size decreases. 

Li, J., Pratt, L. M., and Khan, I. M., Poly(ethylene oxide)/poly(2-vinylpyridine)/lith-ium perchlorate blends as solid polymer electrolytes. Composition/property/structure interrelationship, J. Polym. Sci. Chem. Ed., 33, 1657-1663 (1995). 

Stepanek M, Matejicek P, Humpolickova J, Prochazka K (2005) Reversible aggregation of polystyrene-block-poly(2-vinylpyridine)-block-poly(ethylene oxide) block copolymer micelles in acidic aqueous solutions. Langmuir 21 (23) 10783-10790. doi 10.102 l/la0516680... 

Bronstein, L. H., S. N. Sidorov, P. M. Valetsky, J. Hartmann, H. Colfen, andM. Antonietti. 1999. Induced micellization by interaction of poly(2-vinylpyridine)-block-poly(ethylene oxide) with metal compounds. Micelle characteristics and metal nanoparticle formation. Langmuir 15 (19) 6256-6262. 

Incomplete oxidation can be a problem. Higher recoveries of cysteine and cystine have been achieved by reduction of those amino acids with 2-mercaptoethanol followed by incubation with 4-vinylpyridine. This converts cysteine and cystine to S-(4-pyridylethyl)-L-cysteine, a derivative that can be separated by ion-exchange chromatography. Performic acid oxidation of methionine in the presence of phenol is a suitable method for analysis of cysteine. 

In heme (7a) with poly(4-vinylpyridine) or poly(l-vinyl-2-methylimidazole) in DMF-CH3OH-H2O (9 1 traces) Fe(II) is partly oxidized after one cycle >. 

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