Addition of isocyanides to α‐(methylthio)‐benzylidenamidinium iodides: A surprising access to 2‐(dialkylamino)imidazoles and 3,5‐diamino‐2H‐pyrrolium salts |
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Authors: | Georges Morel Evelyne Marchand Yvelise Malvaut |
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Abstract: | A number of 2‐(dialkylamino)‐5‐(methylthio)imidazoles 2 are obtained by treating the formamidinium iodides 1a,b with isocyanides R3 NC under mild conditions. Reduction of these species can occur in the reaction medium to furnish the corresponding imidazoles 3 . In some cases, double cycloaddition across the imine bond of starting salts 1 also provides the (azetidin‐1‐yl‐methylene)ammonium iodides 4 . Reactions with tert‐butyl and isopropyl isocyanides in refluxing acetonitrile convert the acetamidinium iodide 1c into the 3,5‐diamino‐2H‐pyrrolium salts 7 . Mechanisms are suggested to account for these ring‐closure processes. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:370–376, 2000 |
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