| 摘要 |
1,256,834. Benzimidazole-2-carbamic acid esters. FARBENFABRIKEN BAYER A.G. 19 June, 1970 [26 June, 1969; 13 Feb., 1970], No. 29949/70. Heading C2C. Benzimidazole-2-carbamic acid esters of the formula in which X is hydrogen, halogen, C 1-4 alkyl, or C 1-4 alkoxy and R is C 1-12 alkyl, C 5-8 cycloalkyl or aralkyl, are prepared by reacting the appropriate X-substituted o-phenylenediamine with an N-dichloromethylenecarbamic acid ester RO.CO.N CCl 2 at -10‹ to 40‹ C. in the presence of a base. Suitable bases are alkali metal hydroxides, alkaline earth metal hydroxides, carbonates and hydrogen carbonates and tertiary amines. Examples describe the preparation of the methyl, ethyl, n-butyl, n-octyl and benzyl esters of benzimidazole-2-carbamic acid and the ethyl ester of 5-n-butylbenzimidazole-2-carbamic acid. The N-dichloromethylene carbamic acid esters are obtained by reacting N-dichloromethylenecarbamic acid chloride with the appropriate alcohol in an inert solvent. The benzimidazoles obtained by this process possess fungicidal activity and are used in conventional ,forms to combat plant pathogens. |
