Elaboration of Peptidomimetics Derived from a PADAM Approach: Synthesis of Polyfunctionalised 2(1H)-Pyrazinones via an Unexpected Aromatisation.

When the PADAM (Passerini reaction-amine deprotection- acyl migration) strategy is applied to N-Boc amino acids, the resulting β-acylamino-α-hydroxyamides can be elaborated by secondary- alcohol oxidation, Boc deprotection, and intramolecular cyclisation. When TFA is employed to cleave the Boc group a spontaneous aromatisation to 2(1H)-pyrazinones is observed. [ABSTRACT FROM AUTHOR]