| abstract |
Compounds of the formulan and salts thereof, W being O or S; a being a nitogen-containing heterocyclic ring system; E being O, S(O) m or NR₄ where m is 0-2; E₁ and E₂ being independently CH₂, CH₂CH₂, CH(C₁-C₄ alkyl), C(C₁-C₄ alkyl)₂ or CH(aryl), with the proviso that E₁ and E₂ cannot both be CH₂CH₂; R₁ and R₂ are independently hydrogen, halogen or one of a variety of organic substituents. n The compounds are effective herbicides. |