Heterocyclic Compounds
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ChemInform Abstract: Reactions with Heterocyclic Enaminonitriles: Synthesis of Pyrrolo-(2,3-b)pyridine, Pyrrolo(2,3-d)pyrimidine, and Pyrrole Derivatives.
First published: January 10, 1989
Abstract
Cyclocondensation reaction of ethyl 3-(dicyanomethylene)butyrate (I) with the diazonium salts (II) yields the dihydropyridazines (III) which undergo ring contraction on treatment with zinc/acetic acid, forming the pyrroles (IV).
ChemInform Abstract
Cyclocondensation reaction of ethyl 3-(dicyanomethylene)butyrate (I) with the diazonium salts (II) yields the dihydropyridazines (III) which undergo ring contraction on treatment with zinc/acetic acid, forming the pyrroles (IV). These react with malononitrile (V), ethyl cyanoacetate (VII), formic acid (IX), or formamide (XI), yielding the fused pyrroles (VI), (VIII), (X), or (XII). The pyrrole derivatives (XIV) and (XVI) cannot be cyclized in refluxing ethanolic hydrochloric acid.
