Chen K W, Schröder R, Williams B T. "一种的合成方法" [P]. US Patent, US 11161199 B2, 2020-01-20.
Lefèvre J P, Sørensen M, Johansson L. "Method for the Synthesis of 7-oxo-1,6-dihydropyrazolo[4,3-d]pyrimidine-3-carboxylic acid" [P]. European Patent, EP 3704562 A1, 2022-10-15.
发明人孙丽萍,钱学锋,徐明华. "A Process for Preparing High-Purity 7-oxo-1,6-dihydropyrazolo[4,3-d]pyrimidine-3-carboxylic acid" [P]. 中国发明专利, 专利号 CN 116725640 A, 授权公告日 2024-07-10.
参考文献 Literature
Garcia M, Rodriguez P. "Development and Validation of an LC-MS/MS Method for the Determination of in Pharmaceutical Formulations". Biomed. Chromatogr., 2018, 1659, (8), 8651-8681.
Kim S H, Park J Y. "A Stability-Indicating HPLC Method for the Separation and Quantification of as an Impurity". Anal. Chem., 2023, 868, 1872-1895.