Synthesis and spectroscopic characterisation of N-alkyl quaternary ammonium salts typical precursors of cyanines

Abstract

The synthesis and spectroscopic characterisation of some representative N-alkyl-substituted quaternary ammonium salts derived from benzothiazole, benzoxazole, benzo-selenazole, indole and quinoline are described. These heterocyclic salts, bearing an activated methyl group in the 2-position in relation to the nitrogen atom and N-methyl, -pentyl, -hexyl and -decyl chains, are typical precursors of cyanine dyes.