An expeditious convergent synthesis of a dibromotyrosine alkaloid inhibitor of mycothiol-S-conjugate amidase

A quick, economic synthesis of the alkaloid 1, an inhibitor of mycothiol-S-conjugate amidase (MCA) is reported. Starting from low-cost, commercially available 4-hydroxybenzaldehyde, the nine-step synthesis involved dibromination and coupling with N-acetylglycine to give a stable methyloxazole intermediate 5 which was hydrolyzed, oximated and coupled to agmatine to yield the oxime in ∼30% overall yield. It was not necessary to protect the oxime in the synthetic sequence thereby circumventing a deprotection step.