## STR00001 ## This invention relates to substituted 1,2,5- oxadiazole compounds of formula I, and their N- oxides and salts , and compositions containing the compounds . The invention also , for suppressing undesirable vegetation , relates to the use of 1,2,5- oxadiazole compounds or compositions containing the compounds . In the formula , X 1 , X 2 And X 4 Of the condition that at least one is N, X 1 Is , N or CR 1 At is , X 2 Is , N or CR 2 At is , X 4 Is , N or CR 4 In is R is , for example , hydrogen , cyano , nitro , halogen , C 1 -C 6 - Alkyl , C 3 -C 7 - Cycloalkyl , C 3 -C 7 - Cycloalkyl -C 1 -C 4 - Alkyl , C 1 -C 6 - Haloalkyl , C 2 -C 6 - Alkenyl , C 2 -C 6 - Haloalkenyl , C 2 -C 6 - Alkynyl , C 2 -C 6 - Haloalkynyl , C 1 -C 4 - Alkoxy -C 1 -C 4 - Alkyl , C 1 -C 4 - Haloalkoxy -C 1 -C 4 - Alkyl , O-R a , Z-S (O) n -R b , Z-C (= O) -R c , Z-C (= O) -OR d , Z-C (= O) -NR e R f , Z-NR g R h Is selected from the group consisting of phenyl Z- and Z- heterocyclyl R 1 Is , for example , Z 1 - Cyano , halogen , nitro , C 1 -C 8 - Alkyl , C 2 -C 8 - Alkenyl , C 2 -C 8 - Alkynyl , C 1 -C 8 - Haloalkyl , C 1 -C 8 - Alkoxy , C 1 -C 4 - Alkoxy -C 1 -C 4 - Alkyl , Z 1 -C 1 -C 4 - Alkoxy -C 1 -C 4 - Alkoxy , C 1 -C 4 - Alkylthio -C 1 -C 4 - Alkyl , Z 1 -C 1 -C 4 - Alkylthio -C 1 -C 4 - Alkylthio , C 2 -C 6 - Alkenyloxy , C 2 -C 6 - Alkynyloxy , C 1 -C 6 - Haloalkoxy , C 1 -C 4 - Haloalkoxy -C 1 -C 4 - Alkyl , Z 1 -C 1 -C 4 - Haloalkoxy -C 1 -C 4 - Alkoxy , Z 1 -S (O) k -R 1b , Z 1 - Phenoxy and Z 1 - Is selected from the group consisting heterocyclyloxy R 2 , R 3 Are the same or different , for example , hydrogen , halogen , Z 2 -OH, Z 2 -NO 2 , Z 2 - Cyano , C 1 -C 6 - Alkyl
