3-aryluracil derivatives and their use as herbicides

Abstract From the Canadian patent

3-Aryluracil derivatives of formula, (I) wherein W is a group of formula (a) or (b), wherein the bond to the ring nitrogen atom is made via the carbon atom; R1 is hydrogen, C1-C4alkyl C1-C4haloalkyl C3or C4-alkenyl or C3- or C4-alkynyl; R2 is halogen or cyano; R3 is hydrogen or fluorine; R4 is hydrogen, halogen or C1-C4alkyl; R5 is C1-C4 alkyl or C1-4haloalkyl; R6 and R7 are each independently of the, other hydrogen C1-C8alkyl, C3-C6alkenyl, C3-C6alkynyl C3-C8cycloalkyl, C1-C6haloalkyl, C1-C6alkoxy-C1-C6alkyl C1-C6-alkylthio-C1-, C6alyl, aryl, aryl-C1-C4alkyl heteroaryl or, heteroaryl-C1-C4alkyl; or R6 and R7 together with the carbon atom to which they are bonded form a 3-, 4-, 5- or …