Polyvinylpyridine N-oxide

Fig. 54. Polyvinylpyridine N-oxide, micronized. Gold coating. Cambridge Stereoscan 150 operated at 9.9 kV. APh-R. 213/80, negative 03 941...

Subcutaneous injections of polyvinylpyridine-N-oxide inhibited the development of severe silicosis after intratracheal instillation of quartz DQ 12 in rats and prolonged the life span the total tumour incidence and especially the rate of malignancies... 

Polyvinylpyridine-N-oxide retarded splenic fibrosis of mice given 3 mg quartz intravenously as judged from the hydroxyprohne content of the organ (Dolgner and Pott 1967). 

Polyvinylpyridine-N-oxide (0.5 ig/ml) inhibited the CL completely the quartz-induced CL, but had little effect on asbestos fibre-induced CL. Carbox-ymethylcellulose (1.0 ig/ml), however, reduced CL caused by chrysotile but had no effect on CL induved by the other particles. 

In the dehydration of aldehydes to form nitriles, Ley and colleagues used a polymer-supported hydrazine (Scheme 6.3). The immobilized hydrazine was reacted with aldehydes to give a hydrazone. Subsequent oxidation with mCPBA (meta-chloroperoxybenzoic acid) rendered the corresponding N-oxide, which spontaneously eliminated to form the desired nitrile [10]. Polyvinylpyridine was used as a scavenger for excess mCPBA. 

Polymers from 16C and 18C, and presumably 17C, may be hydrogenated to form the corresponding poljrvinylpiperidines (6), or oxidized to the corresponding water-soluble N-oxide. The polyvinylpyridines may also be readily derivatized via quaternization with an appropriate alkylating agent, such as methyl iodide. The monomeric quats are readily water-soluble but can be prone to spontaneous polymerization above critical concentrations (216). The nature of the counterion can also affect the propensity of the quaternized monomers to autopolymerize. 

---