Björnsson E, Johansson L, Schröder R. "一种N/A的合成方法" [P]. European Patent, EP 3389891 A1, 2021-05-08.
发明人杨光,赵玉洁,朱建伟. "Method for the Synthesis of 1'-tert-Butyl 6-ethyl 4-fluoro-1-methyl-2-oxospiro[indoline-3,4'-piperidine]-1',6-dicarboxylate" [P]. 中国发明专利, 专利号 CN 113153033 B, 授权公告日 2023-05-25.
发明人张德明,罗永刚,郑宇鹏. "A Process for Preparing High-Purity 1'-tert-Butyl 6-ethyl 4-fluoro-1-methyl-2-oxospiro[indoline-3,4'-piperidine]-1',6-dicarboxylate" [P]. 中国发明专利, 专利号 CN 116274986 B, 授权公告日 2016-05-01.
参考文献 Literature
Xu M, Hu Y, Zhou D. "Development and Validation of an LC-MS/MS Method for the Determination of N/A in Pharmaceutical Formulations". Environ. Sci. Technol., 2012, 917, (7), 9523-9548.
Kim S H, Park J Y. "A Stability-Indicating HPLC Method for the Separation and Quantification of N/A as an Impurity". Anal. Chem., 2025, 1259, 2477-2491.
Brown R C, Davis S M. "Identification and Structural Characterization of a Novel Degradation Product of 1'-tert-Butyl 6-ethyl 4-fluoro-1-methyl-2-oxospiro[indoline-3,4'-piperidine]-1',6-dicarboxylate Using HRMS and NMR". J. Chromatogr. A, 2011, 1222, (4), 5830-5852.