2,3-dicyano 6 phenyl pyrazine herbicides

Abstract

Novel 2,3-dicyanopyrazine derivatives of the formula ##STR1## wherein A represents a hydrogen atom, a lower alkyl group, an unsubstituted or substituted phenyl group, a benzyl group, or a group of the formula --ZR.sub.1 in which Z represents an oxygen or sulfur atom and R.sub.1 represents an unsubstituted or substituted lower alkyl group, a lower alkenyl group, a lower alkynyl group, an unsubstituted or substituted phenyl group, or an unsubstituted or substituted benzyl group; and B represents a halogen atom, an alkyl group containing at least 3 carbon atoms, a phenyl group having a substituent at the ortho- and/or meta-position of the benzene ring, a group of the formula ZR.sub.1 in which Z and R.sub.1 are as defined, or a group of the formula ##STR2## in which R.sub.2 and R.sub.3, independently from each other, represent a hydrogen atom, an unsubstituted or substituted lower alkyl group, a lower alkenyl group, a cycloalkyl group, an unsubstituted or substituted phenyl group, or an unsubstituted or substituted benzyl group, with the proviso that R.sub.2 and R.sub.3 do not represent a hydrogen atom at the same time, and R.sub.2 and R.sub.3 together may form a 3- to 7-membered heterocyclic ring together with the nitrogen atom to which they are bonded, said heterocyclic ring optionally containing an additional hetero atom; and processes for production thereof. These compounds have high herbicidal activity, and are useful as active ingredients of herbicides.