Reaction of α-halo- and α,α-dihalo-β-oxoaldehydes with o- and m-phenylenediamines

Article abstract of DOI:10.1007/bf02495653

α-Halo-β-oxoaldehydes react with o- and m-phenylenediamines to give α-halo-β-oxoenamines. In the case of o-phenylenediamine, the initially formed monoenamine undergoes concurrent intramolecular cyclization to give benzimidazole and a halocarbonyl compound. α,α-Dihalo-β-oxoaldehydes react with o- and m-phenylenediamines according to the haloformic decomposition scheme involving formylation of amino groups.