| 摘要 |
2-Hydrazinobenzimidazole derivatives of the formula (I) <IMAGE> in which X represents CH or nitrogen, R<1> represents hydrogen or alkyl, R<2> represents alkyl, trihalomethyl, alkoxy, halogen, nitro, carboxyl, the sulpho radical, aminosulphonyl or trihalomethylsulphonyl, in the event that X represents CH, n represents 0, 1, 2, 3 or 4, or, in the event that X represents nitrogen, n represents 0, 1, 2 or 3, are obtained in very good yields, in high purity and under mild conditions when 2-mercaptobenzimidazole derivatives of the formula (II) <IMAGE> in which X, R<1>, R<2> and n have the abovementioned meaning are converted with hydrogen peroxide in an aqueous-alkaline solution in the presence of an oxidation catalyst at temperatures between 0 DEG C and 95 DEG C into an alkali metal salt of the compounds of the formula (III) <IMAGE> in which X, R<1>, R<2> and n have the abovementioned meaning and Me<+> represents an alkali metal cation, and the resulting reaction solution is reacted with hydrazine hydrate under atmospheric pressure at temperatures between 25 DEG C and 90 DEG C without isolation of the compounds of the formula (III) to give the compounds of the formula (I).
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