Polycondensed Nitrogen Heterocycles. Part 15. Reactivity of 3-Diazopyrroles. 3. 1H-Pyrrolo[3,2-c]cinnoline and Pyrrolo[3,4-c]pyridazine

Abstract
3-Diazopyrroles were prepared and refluxed in acetic acid. In the case of 5a [4-substituted 3-diazo-2-(3-methoxyphenyl)-5-methylpyrroles], an intramolecular coupling reaction between the diazonium group and the methoxyphenyl substituent in the 2-position leads to the 1H-pyrrolo [3,22-c]-cinnoline derivative while in the case of 5b [4-substituted 3-diazo-2-(3-methoxylphenyl)-5-methylpyrroles] an intramolecular coupling with the acetyl group in the 4-position affords the pyrrolo [3,4-c] pyridazine derivative.
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