Abstract
3-(α-haloacyl)-2,4-dialkylpyrazolo[1,5-a]benzimidazoles can be obtained either by brominating 3-acetylpyrazolo[1,5-a]benzimidazoles with bromine in acetic acid, or by acylating the 3-unsubstituted pyrazolobenzimidazoles with haloacetic halides. Halogenation of 3-acetylpyrazolo[1,5-a]benzimidazoles with bromine in acetic acid in the presence of sodium acetate, and bromination with N-bromosuccinimide or 1-chlorobenzotriazole, result in deacylation to give 3,6(7)-dibromo- and 3-chloropyrazolo[1,5-a]benzimidazoles. The mono- and trihaloketones obtained have been used to prepare the corresponding aminoketones, the 3-carboxylic acid, and its derivatives.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 43–48, January, 1988.
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Kuz'menko, T.A., Kuz'menko, V.V. & Simonov, A.M. 3-α-Halocarbonyl derivatives of pyrazolo[1,5-a] benzimidazole and their reactions. Chem Heterocycl Compd 24, 36–40 (1988). https://doi.org/10.1007/BF00475562
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DOI: https://doi.org/10.1007/BF00475562