Herbicidal 1,1'-disubstd-4,4'-bipyridylium - salts

摘要

Title cpds. are made by oxidn. of correspg. 1,1'-disubstd.-1,1',4,4-tetrahydro-4,4'-ipyridyls with an org. cpd. having a redox potential in aq. soln. more positive than -1.48v with respect to the satd. calomel electrode and reacting with a hydrion to give an anion having a redox potential more positive than -0.45v, e.g. indanetrione or methylene blue.