51072-36-7Relevant articles and documents
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Sugasawa,Tachikawa
, p. 2043 (1959)
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Asymmetric Synthesis of a Key Dextromethorphan Intermediate and Its Analogues Enabled by a New Cyclohexylamine Oxidase: Enzyme Discovery, Reaction Development, and Mechanistic Insight
Chen, Fener,Huang, Zedu,Li, Zhining,Lin, Juan,Wang, Jiaqi,Wang, Zexu,Wu, Xiaofan
supporting information, p. 5598 - 5614 (2020/05/19)
(S)-1-(4-Methoxybenzyl)-1,2,3,4,5,6,7,8-octahydroisoquinoline [(S)-1-(4-methoxybenzyl)-OHIQ, (S)-1a] is a key synthetic intermediate in the industrial production of dextromethorphan, one of the most widely used over-the-counter antitussives. We report here that a new cyclohexylamine oxidase discovered by genome mining, named CHAOCCH12-C2, was able to completely deracemize 100 mM 1a under Turner's deracemization conditions to afford (S)-1a in 80% isolated yield and 99% ee at a semipreparative scale (0.4 mmol). When this biocatalytic reaction was scaled up to a gram scale (5.8 mmol), without reaction optimization (S)-1a was still isolated in 67% yield and 96% ee. The relatively higher kcat determined for CHAOCCH12-C2 was rationalized as one major factor rendering this enzyme capable of oxidizing 1a effectively at elevated substrate concentrations. Protein sequence alignment, analysis of our co-crystal structure of CHAOCCH12-C2 complexed with the product 1-(4-methoxybenzyl)-3,4,5,6,7,8-hexahydroisoquinoline [1-(4-methoxybenzyl)-HHIQ, 2a], and the structure-guided mutagenesis study together indicated L295 is one of the critical residues for this efficient enzymatic oxidation process and supported the presence of two cavities as well as a catalytically important "aromatic cage" formed by F342, Y433, and FAD. The synthetic applicability of CHAOCCH12-C2 was further underscored by the stereoselective synthesis of various enantioenriched 1-benzyl-OHIQ derivatives of potential pharmaceutical importance at a semipreparative scale.
Method for preparing levallorphan tartrate
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, (2017/08/29)
The invention provides a method for preparing levallorphan tartrate and belongs to the technical field of drug and chemical synthesis. The method takes methoxyphenylacetic acid and 2-(cyclohexenyl)ethylamine as initial raw materials, and comprises nine reaction steps such as acylation condensation, Bischler-Napieralski ring formation reaction, imine reduction, ether bond hydrolysis, resolution, N-alkylation, Grewe cyclization reaction, and salifying. According to the method, the levallorphan tartrate and each intermediate can be obtained at high yield and high purity, and the method can serve as an industrial method for performing large-scale production.
