One‐Pot Access towards 4,5‐Disubstituted 2‐Amino‐1<i>H</i>‐imidazoles Starting from Mannich Substrates and their Transformation Utilities

摘要

An efficient protocol for the preparation of 4,5‐functionalised 2‐amino‐1 H ‐imidazoles as fragment‐like structures was developed in isolated yields up to 95 %. The demonstrated one‐pot manner includes an intramolecular oxidative annulation and ring cleavage sequence starting from Mannich precursors. The suggested one‐pot sequential synthetic methodology is easy to apply in automatic and robotic chemistry laboratories for which a rapidly increasing demand is foreseen because of the ongoing revolution in the field of continuous manufacturing of pharmaceutical drug substances and products. Further transformation utilities such as Groebke–Blackburn–Bienaymé 3CR and the formation of marine alkaloid analogs were also represented.