3-Alkylpyridinium polymer

Kaiser et al. have reported a general entry for the selective synthesis of dimeric macrocycles like cyclostellettamines and for polymeric natural products [41]. It uses the Zincke reaction by which it is possible to control the number of units in a 3-alkylpyridinium polymer. As summarized in Fig. (33), the reaction of the free amine 89 with the Zincke salt 88 gives the dimer 90 (route b) which, after terminal amine deprotection and DNB functionalization at the A-pyridine centre, gives the cyclic dimer, as in the synthesis of cyclostellettamine B. Otherwise, compound 90 furnishes both the protected dimer 91 and the free linear dimer, which, refluxed together in butanol, give the linear tetramer (route c). By the same iterative sequence, the linear octamer was obtained from the tetramer, and from the latter the hexadecamer. 

Bunc, M., Sepdc, K., Turk, T, and Suput, D. (2000) In vivo effects of head-to-tad 3-alkylpyridinium polymers isolated from the marine sponge Reniera sarai. Pjlugers Arch. Eur. J. Physiol, 440 (Suppk), R173-R174... 

Malovrh, P., Sepcic, K., Turk, T., and Macek, P. (1999) Characterization of hemolytic activity of 3-alkylpyridinium polymers from the marine sponge Reniera sarai. Comp. Biochem. Physiol, 124C, 221-226. 

Sepcic, K., Marcel, V., Klaebe, A., Turk, T, Suput, D., and Fournier, D. (1998) Inhibition of acetylcholinesterase by an alkylpyridinium polymer from the marine sponge, Reniera sarai. Biochim. Biophys. Acta, 1387, 217-225,... 

These polymers are essentially less toxic (factor of 2-10 at LDs0) and partially very much longer active than free sarkolysin. An increase in activity, however, is not attained. Here, the mode of action is, however, not clear because bifunctional chloro-alkylamine derivatives ( N-Lost derivatives) seem to be necessary to show some activity. Possibly in this case the alkylpyridinium compound decomposes into a derivative of ethylene or the chloroethyl group is formed again so that a second reactive group is formed besides the chloroethyl residue which is still present. 

There are few reports of antimicrobial activity for alkylpyridinium compounds. However, the numbers are difficult to compare since authors have been using different bacterial strains or fungi in their assays. Overall, it appears that monomers are superior in antimicrobial activity over to oligomers and polymers, but again, this is not a general rule. 

Figure 6.39 Separation factors as a function of the number of methylene units between ionic sites of cationic polymers used in the formation of polyion complex membranes (pervaporation of 90% aqueous ethanol solution at 30 °C). Polyion complex membranes prepared by ion complex formation between k-carrageenan (anionic polymer) and poly[l,3-bis(4-alkylpyridinium)propane bromidejs (cationic polymer) with different numbers of methylene units between ionic sites.

Biodegradable polymers can be obtained by introducing pyridinium groups such as N-alkylpyridinium groups or N-arylpyridin-ium groups into the backbone of a synthetic vinyl polymer and subsequently quatemizing the pyridinium groups with chlorine or... 

The properties of the microenvironment of soluble synthetic polymers such as polymethacrylamide (PMA), poly(2-hydroxyethyl methacrylate) (PHEMA), poly(2-vinylpyridine) (P-2VP), poly(4-vinylpyridine) (P-4VP), poly(methyl methacrylate) (PMMA), poly(butyl methacrylate) (PBMA), polystyrene (PS), poly(4[5]-vinylimidazole) (PVIm), and poly(N-2-hydroxypropyl methacrylamide) (PHPMA) and cross-lined polymers were studied by the shift and shape of the band in electronic spectra of a solvatochromic "reporter" molecule embedded in polymer chains. Preferential interaction of parts of the polymer molecule with a reporter and the shielding of interactions between solvent molecules and a reporter molecule of a polymer causes a shift and broadening of its solvatochromic band. This shift is mechanistically interpreted as a change in the polarity of the microenvironment of a polymer in solution in comparison with polarity of the solvent used. 4-(4-Hydroxystyryl)-N-alkylpyridinium-betaine, spiropyran-merocyanine, and l-dimethylamino-5-sulfonamidonaphthalene (Dansyl) reporters were used. In almost all cases the polarity of the polymer microenvironment was lower than that of the solvent. At the same time, the dependence of the nature of the environment on the distance of the reporters from the polymer chain was studied. 

Structures equivalent to those described above, and generally called polymeric alkylpyridinium salts (PAPS), have been isolated from Reniera sarai harvested in the Adriatic Sea at depths of 15—40 m. These polymers have anticholinesterase, cytotoxic and hemolytic activities, but the oligomers of molar mass less than 3000 Da show no activity (Sepcic et al., 1997,1998 Malovrh et al., 1999 Brmc et al., 2000, 2002). 

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