E.S.R. observation of enamine radical cations from thiamine (vitamin B1) and related compounds

Abstract

Reactions of thiamine and thiazolium salts with hydroxyalkyl radicals yield enamine radical cations by radical and/or formal hydrogen addition at the CH– position of the thiazolium ring. Their high resolution e.s.r. data lead to reinterpretations of previous spectroscopic observations on thiamine radicals and suggest a structure for a radical observed during the enzymic action of pyruvate:ferredoxin oxidoreductases from archaebacteria and anaerobic eubacteria.