Ampere‐Level Electrosynthesis of ¹⁵N‐Labeled Oximes by Alloy Synergy Activation and Hydroxylamine Overhydrogenation Inhibition

Abstract 15 N‐labeled molecules are essential for industrial drug development and medical imageology. However, the synthesis of 15 N‐labeled molecules suffers from the complex procedure of de novo synthesis and harsh conditions. Here, we propose an electrochemical strategy to synthesize 15 N‐labeled oximes ( 15 N‐oximes) from 15 N‐labeled nitrites ( 15 NO 2 − ) and aldehydes/ketones. Matching the adsorption and activation of H 2 O and 15 NO 2 − and inhibiting 15 NH 2 OH overhydrogenation are the keys to realizing efficient ampere‐level electrosynthesis of 15 N‐labeled oximes. A bismuth−molybdenum (BiMo) alloy catalyst is subsequently designed, in which Bi acts as the 15 NO 2 − activation site, whereas Mo serves as the H 2 O activation site. The precisely controlled atomic ratio of Mo and Bi ensures that there is sufficient but not excessive active hydrogen provided for 15 NO 2 − hydrogenation and therefore accelerates the reaction rate. Moreover, Mo incorporation increases the energy barrier of 15 NH 2 OH overhydrogenation and thus improves the Faradaic efficiency (FE) of 15 N‐oxime. This strategy enables scale‐up electrosynthesis with a 76% FE and 88% yield at a current of 3.0 A to obtain 3.5 g of 15 N‐cyclohexanone oxime within 1.5 h. The application potential is highlighted by the methodological universality of diverse 15 N‐oximes, the extended synthesis of 15 N‐labeled drug molecules and their application in 2D magnetic resonance imaging visualization.