SYNTHESIS AND PROPERTIES OF OLIGOAMINOPYR IDINES

The conditions, regularities, and products of oxidative polymerization of 2- and 4-aminopyridines with NaOCl in alkaline and acidic media we re studied. As the molar ratio NaOCl : aminopyridines reaches 1 : 2 - 1 : 3, the one-hour yield of oligomeric products at 298 K increases to 77 and 90% in alkaline and acidic media, respectively. In optimum con ditions, 2-aminopyridine produces more oligomeric products than 4-amin opyridine does. In the initial stage of the oxidative polymerization, only the formation of dimers and trimers occurs. After one hour, molec ular mass distribution curves show the peak characteristic of high-mol ecular-mass fractions with molecular masses varying from 7200 to 10 05 0. The portion and molecular masses of this fraction are markedly high er in oligomers obtained in acidic conditions. The observed bimodality of molecular mass distribution curves of oligoaminopyridines may be a ttributed to the polymer coupling occurring at active centers of vario us (radical or cation-radical) natures.