Process for substituting and dequaternizing pyridylethyl quaternary salts of pyridine and bypyridine bases

摘要

{PG,1 A process for dequaternizing a 2-(2-pyridyl)ethyl or 2-(4-pyridyl)ethyl quaternary salt of a pyridine or bipyridine base comprising the step of heating or reacting the pyridylethyl quaternary salt with a caustic material such as sodium hydroxide. Also included is a process for preparing a second pyridine base (or a bipyridine base) in which a first pyridine base is initially selected and its 2-(2-pyridyl)ethyl or 2-(4-pyridyl)ethyl quaternary salt or its acid salt prepared. An electrophilic, nucleophilic or coupling reaction can then be performed on the quaternary salt to change the substituent or to form the bipyridyl coupling and the resultant salt dequaternized with a caustic material, such as sodium hydroxide, to produce a second pyridine or a bipyridine base.