Isoxazole derivatives and their use as herbicides

A compound of the formula:

• or an agriculturally acceptable salt thereof, wherein:
• R is a member selected from the group consisting of lower alkyl, haloalkyl, alkoxyalkyl, cycloalkyl, and alkenyl, each of which is optionally substituted with —SR2 or —OR2;
• R1 is a member selected from the group consisting of lower alkyl, haloalkyl and phenyl, optionally substituted;
• R2 is lower alkyl;
• X and Y are members independently selected from the group consisting of hydrogen, hydroxyl, halogen, cyano, alkylsulfenyl, alkylsulfinyl, alkylsulfonyl, acyloxy, carbamoyloxy, alkoxy, alkoxycarbonyl, alkylsulfonyloxy, amino, substituted amino, acylamino, sulfamoyloxy, sulfamyl;
• or taken together are selected from the group consisting of ═O, —S(CH2)mS— and —O(CH2)mO—, in which m is an integer of from 2 to 3;
• Ar is an aromatic ring moiety optionally substituted with from one to four substituents independently selected from the group consisting of halogen, lower alkyl, haloalkyl lower alkoxy, lower haloalkoxy, lower alkoxyalkyl, lower alkylthioalkyl, lower alkylsulfonylalkyl, lower alkylsulfinylalkyl, R3S—, R3SO—, R3SO2—, R3SO3—, nitro, cyano, lower alkoxyalkoxy, —COR4, —CO2R4, —C(═NOR4), —NR5SO2R4, —NR4R6, —NR3R4, and wherein two substituents on adjacent positions of the aromatic ring, together with the two atoms to which they are attached, form a 5- to 7-membered ring optionally substituted;
• R3 is lower alkyl, haloalkyl, or (substituted)phenyl;
• R4 is hydrogen or lower alkyl;
• R5 is hydrogen, lower alkyl, alkenyl, alkynyl, cycloalkyl or (substituted)phenyl;
• R6 is —COR4 or —CO2R4;
• and
• Z is —S—,—SO— and —SO2—.