A simple and efficient one‐pot oxidation synthesis of N‐1‐piperidonyl amides was successfully developed through the double oxidation of hydrazides (involving hydrazonium formation, azodioxy‐carbonyl compounds generation, and α‐carbon oxidation) by using meta‐chloroperbenzoic acid (mCPBA). The convenient oxidation method was also extended to Rimonabant analogue. The lactam oxidized Rimonabant analogue was first successfully synthesized for demonstrating the construction and characterized by NMR spectroscopic methods and the single‐crystal X‐ray diffraction study (ORTEP). N‐1‐Piperidonyl amides were firstly oxidized by mCPBA from N‐1‐piperidinyl amides. The new developed method was also extended to Rimonabant analogue, N‐(piperidin‐1‐yl)‐1H‐1,2,4‐triazole‐3‐carboxamide, and N‐(azepan‐1‐yl)benzamide, especially for Rimonabant analogue. This work presented a significant advancement in the synthesis of oxidized N‐1‐piperidonyl amides that had important implications for the further development of potential drugs and the study of the oxidized metabolite.