恩塞芬汀（Ensifentrine）于2024年6月被FDA批准上市．现有文献只有该药物的核磁共振（NMR）波谱数据，缺乏详细的原子归属，这不利于恩塞芬汀的杂质鉴定和质量控制，且该化合物存在多个季碳和氮原子，在NMR信号归属上存在一定难点．本文利用Bruker Avance III 400 MHz NMR波谱仪，获得恩塞芬汀的¹H、¹³C以及二维NMR谱，完整归属了该化合物的¹H和¹³C NMR信号．与现有文献不同的是，本文用DMSO-d₆做溶剂，提高了样品溶解度，可准确指认活泼氢信号的耦合关系，同时使样品的二维NMR谱信号清晰可辨．本文为基于NMR波谱学的恩塞芬汀原料药结构解析、含量测定和质量控制提供了研究基础．

Ensifentrine was approved for marketing by the U.S. Food and Drug Administration (FDA) in June 2024. To date, however, the literature has provided only the raw NMR spectral data of this drug without detailed signal assignments, which hinders impurity identification and quality control for ensifentrine. Furthermore, the compound contains multiple quaternary carbon and nitrogen atoms, presenting challenges in assigning NMR signals. In this study, we employed a Bruker Avance III 400 MHz NMR spectrometer to acquire ¹H, ¹³C, and two-dimensional NMR spectra of ensifentrine, and fully assigned all ¹H and ¹³C signals. Notably, unlike previous reports, we utilized DMSO-d₆ as the solvent, which enhanced sample solubility, permitted unambiguous identification of the coupling relationships of active hydrogen signals, and yielded well-resolved two-dimensional NMR spectra. This work provides a reference for NMR-based structural analysis, content determination, and quality control of the active pharmaceutical ingredient (API) ensifentrine.