BENZIMIDAZOLES

1421674 7-Amino- or nitro-5-trifluoromethybenzimidazoles UNITED STATES BORAX & CHEMICAL CORP 6 Feb 1974 [20 Feb 1973 23 March 1973] 05381/74 Heading C2C Novel compounds of the formula wherein R 1 and R 2 , same or different, are H or C 1-6 alkyl or cycloalkyl; Y is -NO 2 or -N(R 3 ) 2 ; when Y is -NO 2 , X is in the 6-position and is halo or C 1-6 alkoxy and n=0 or 1; when Y is -N(R 3 ) 2 X is halo, C 1-6 alkoxy or -N(R 3 ) 2 and n=0, 1 or 2; R 3 is H or C 1-6 alkyl or cycloalkyl and R 1 and R 2 together contain at least one C atom, are prepared (a) by reducing a compound of general formula to give the product with Y=-N(R 3 ) 2 (b) reacting a compound of formula with a carboxylic acid R 2 COOH or a carboximidate of formula where R1 is a C 1-6 alkyl or cycloalkyl group or (c) nitration of a 7-H benzimidazole derivative. Amongst numerous examples, the compounds 7 - amino - 6 - chloro - 1 - ethyl - 2 - methyl - 5- trifluoromethylbenzimidazole and 7 - nitro- 6 - methoxy - 1 - ethyl - 2 - methyl - 5 - trifluoromethyl-benzimidazole are prepared. N - ethyl - 3 - chloro - 4 - trifluoromethyl - 6- nitro - aniline is obtained by treating the 1-chloro derivative with ethylamine. 1 - Ethyl - 2 - methyl - 5 - trifluoromethyl - 6- dimethylamino - 7 - nitro - benzimidazole is prepared from the corresponding 6-chloro derivative and dimethylamine. N-ethyl-2- amino - 4 - triflxcoromethyl - 5 - methoxy aniline, N - ethyl - 2 - amino - 4 - trifluoromethyl - 5- chloro - aniline and N - ethyl - 2,6 - diamino - 4- trifluoromethyl aniline are obtained by reduction of the corresponding mono- or di-nitro compounds. N - ethyl - 2 - nitro - 4 - trifluoromethyl - 5- methoxy aniline is prepared by treating the 5- chloro derivative with methanol. 6 - Methoxy- and 6 - chloro - 1 - ethyl - 2- methyl - 5 - trifluoromethyl - benzimidazoles are obtained from cyclizing the appropriate 2- amino-N-ethyl anilines with ethyl methylcarboximidate. Herbicidal compositions comprise the novel compounds and a carrier.