(Z)-2-(2-Aminothiazol-4-yl)-2-[(1-tert-butoxycarbonyl-1-methylethoxy)imino]acetic Acid-D6 is an intermediate in the synthesis of Aztreonam-d6 (A965202), which is an isotope labeled Azetreonam (A965200), the first totally synthetic monocyclic β-lactam antibiotic.