The following report describes novel methodology for the rapid synthesis of unique conformationally constrained norstatine analogs of potential biological relevance. A PADAM (Passerini reaction–Amine Deprotection–Acyl Migration reaction) sequence is followed by a TFA-mediated microwave-assisted cyclization to generate the final benzimidazole isostere of the norstatine scaffold in moderate to good yields. The applicability of this solution phase methodology to the preparation of a small collection of compounds is discussed.The following report describes novel methodology for the rapid synthesis of unique conformationally constrained norstatine analogs of potential biological relevance. A PADAM (Passerini reaction–Amine Deprotection–Acyl Migration reaction) sequence is followed by a TFA-mediated microwave-assisted cyclization to generate the final benzimidazole isostere of the norstatine scaffold in good yields. The applicability of this solution phase methodology to the preparation of a small collection of compounds is discussed.

This Letter reveals a unique, user-friendly, concise two-step, one-pot protocol for the synthesis of highly substituted quinoxalines. Conducting the Ugi reaction with appropriately functionalized classical Ugi reagents with subsequent acid treatment of the Ugi adduct affords collections of diversified quinoxalines in good to excellent yields. The methodology exploits what may be viewed as a ‘convertible carboxylic acid’, which in addition may be captured in an intramolecular sense to generate structurally complex 2-benzimidazolylquinoxalines in a mere two steps.