CYANBENZOFURAN DERIVATIVES, PROCESSES FOR THEIR PREPARATION AND THEIR USE IN HERBICIDAL COMPOSITIONS; CYANOBENZENE, BENZODIOXEPINE, BENZODIOXAPHOSPHEPINE AND BENZODIOXATHIEPINE DERIVATIVES

摘要

The invention provides herbicidally-active 2,3-dihydro-5-cyanobenzofurans of the formula: (I) (wherein: R1 and R2 together represent =O or R1 represents hydrogen and R2 represents hydrogen, hydroxy, alkoxy, acyloxy, alkoxycarbonyloxy, alkylthiocarbonyloxy, halogen, isothiocyanato, amino, alkylamino, dialkylamino, arylamino, acylamino, alkoxycarbonylamino, alkylthiocarbonylamino, N-bonded heterocyclyl, cyano or alkylthio; R3 and R4 together represent alkylene or each represent hydrogen or alkyl; and R5, R6 and R7, which may be the same or different, each represent hydrogen, halogen, alkyl, alkoxy, acyl or cyano), processes for their preparation and herbicidal compositions containing them.