Synthesis of perdeuterio‐N‐(1‐oxyl‐2,2,6,6‐tetramethyl‐4‐piperidinyl)maleimide, a highly sensitive spin probe

Abstract
Perdeuterio‐N‐(1‐oxyl‐2,2,6,6‐tetramethyl‐4‐piperidinyl)‐maleimide has been prepared to improve sensitivity and resolution in its ESR spectrum. The synthesis involved modifications of procedures known for the corresponding protonated analog. Spectral data are presented for the product to establish isotopic purity. A five‐fold enhancement of the ESR signal for the title compound relative to the proton counterpart has been observed.