Reaction of 2,2,5,5-tetramethylpyrrolidin-1-oxyl-3-carboxylic acid (I) with 6-amino-2,2-dimethyl-1,3-dioxepan-5-ol (II) yields 2,2,5,5-tetramethylpyrrolidin-1-oxyl-3-carboxylic acid (5-hydroxy-2,2-dimethyl-1,3-dioxepan-6-yl)amide (III). Subsequent acidic hydrolysis gives NAT.