Patent ID: 6087504
Filing Date: 2000-07-11
Classification: C07D

Abstract:
An improved process for the preparation of 1,1'-dialkyl-4,4'-bipyridinium salt of the formula II: ##STR4## wherein R is an alkyl group having 1 to 10 carbon atoms; X is a chlorine atom, bromine atom, or a sulfate group, comprising the steps:(1) by the coupling of 1-alkylpyridinium salt with a base in the presence of an alkaline metal cyanide in an organic solvent;(2) filtering off the cyanide as divalent transitional metal cyanide by quenching the reaction mixture in step (1) with an aqueous solution of divalent transitional metal salt; and(3) oxidation of the filtrate in step (2) with suitable oxidation reagent to afford the 1,1'-dialkyl-4,4'-bipyridinium salt.