Process for the preparation of C.sub.1 -C.sub.4 -alkyl or C.sub.1 -C.sub.4 -alkoxy and unsubstituted 2-(cyanomethyl)benzimidazole

Abstract

Process for the preparation of substituted and unsubstituted 2-(cyanomethyl)benzimidazole A process for the preparation of substituted or unsubstituted 2-(cyanomethyl)benzimidazole, of the formula (I) ##STR1## which comprises reacting an o-phenylenediamine of the formula (II) ##STR2## in which R.sup.1 is C.sub.1 -C.sub.4 -alkyl or C.sub.1 -C.sub.4 -alkoxy, preferably methyl or methoxy, and n is an integer from 0 to 2, preferably 0 or 1, in particular 0, with a cyanoacetic ester of the formula (III) NC--CH.sub.2 --COOR.sup.2 (III) in which R.sup.2 is unsubstituted or substituted, linear, branched or cyclic C.sub.2 -C.sub.12 -alkyl and 1 to 3 CH.sub.2 groups of the alkyl radical can in each case be replaced by oxygen, at a temperature of 150.degree.-175.degree. C. in a halogen-free inert solvent whose boiling point is 150.degree. C. or more, or in a mixture of two or more of such solvents, without adding an aromatic sulfonic acid as catalyst. Using the process according to the invention, 2-(cyanomethyl)benzimidazoles are prepared without a catalyst in good yields and high purity.

Dependencies are inferred from the claim text.