142569-69-5Relevant articles and documents
Ir/SpiroPAP Catalyzed Asymmetric Hydrogenation of a Key Intermediate of Montelukast: Process Development and Potential Impurities Study
Zhu, Guo-Liang,Zhang, Xiang-Dong,Yang, Li-Jun,Xie, Jian-Hua,Che, Da-Qing,Zhou, Qi-Lin,Yan, Pu-Cha,Li, Yuan-Qiang
, p. 81 - 85 (2016)
An efficient and robust process for the asymmetric hydrogenation of a key intermediate of Montelukast using the highly efficient and selective chiral spiro catalyst Ir/SpiroPAP is reported. The developed process was conducted at mild reaction temperature (30 °C) under a hydrogen pressure of 20 atm with low catalyst loading (S/C = 30000) and afforded the desired chiral alcohol intermediate in 99.5% ee. This process currently has been carried out at 30 kg scale. The process-related impurities (impurities I-V) were also identified, synthesized, and characterized by LC-MS and NMR techniques.
Lutidine-Based Chiral Pincer Manganese Catalysts for Enantioselective Hydrogenation of Ketones
Zhang, Linli,Tang, Yitian,Han, Zhaobin,Ding, Kuiling
supporting information, p. 4973 - 4977 (2019/03/17)
A series of MnI complexes containing lutidine-based chiral pincer ligands with modular and tunable structures has been developed. The complex shows unprecedentedly high activities (up to 9800 TON; TON=turnover number), broad substrate scope (81 examples), good functional-group tolerance, and excellent enantioselectivities (85–98 % ee) in the hydrogenation of various ketones. These aspects are rare in earth-abundant metal catalyzed hydrogenations. The utility of the protocol have been demonstrated in the asymmetric synthesis of a variety of key intermediates for chiral drugs. Preliminary mechanistic investigations indicate that an outer-sphere mode of substrate–catalyst interactions probably dominates the catalysis.
Process for preparing montelukast and precursors thereof
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Page/Page column 4, (2008/06/13)
The present invention provides a process for stereoselectively reducing 2-[3-[3-[2-(7-chloro-2-quinolinyl)ethenyl]-phenyl]-3-oxopropyyl]benzoic-acid methyl ester, to produce to produce methyl 2-[3-(S)-[3-[2-(7-chloro-2-quinolinyl)-ethenyl]phenyl]-3-hydroxypropyl]benzoate, and a process for producing montelukast or a salt thereof. The present invention further provides a process for purifying methyl 2-[3-(S)-[3-[2-(7-chloro-2-quinolinyl)-ethenyl]phenyl]-3-hydroxypropyl]benzoate. The reduction process of the present invention uses a chiral reagent and can produce the desired reduction product in high enantiomeric excess (ee).