Synthetic Approach to the Natural <i>N</i>‑Nitrosohydroxylamino Tetramic Acid JBIR-141

An analogue of the <i>Streptomyces</i> metabolite JBIR-141, featuring a delicate <i>N</i>-nitrosohydroxylamine, a 3-acyltetramic acid, and an oxazoline, was synthesized by a convergent strategy from l-alanine, l-threonine, and l-glutamic acid. Key steps were the cyclization of an Ala–Thr derivative to give the oxazoline, a Dieckmann condensation affording the 3-acyltetramic acid, and the <i>N</i>-nitrosation of a hydroxylamino derivative of glutamic acid. An adequate protecting group strategy was established for coupling the three building blocks.