Chemical Constitution and Activity of Bipyridylium Herbicides, X1 3-Substituted-6,7-dihydrodipyrido[1,2-a: 2′,1′-c]-pyrazinediium Dibromides and Related Compounds

Abstract

The synthesis of 3-substituted-6,7-dihydrodipyrido-[1,2-α:2′,1′-c]-pyrazinediium dibromides is described. The 3-alkoxy and 3-carbomethoxy derivatives can be regarded as reversible one electron transfer systems. The most active compound is the 3-methoxy derivative which is a very effective post-emergent herbicide at 1-2 kg/hectare