Water → rac-(1R,3S)-3-aminocyclohexane-1-carboxylic acid

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A 7% (w/v) stock solution of hydrazoic acid in CHCl3 (196 ml, 0.32 mol, the stock solution was prepared by adding 400 g of NaN3 into 400 ml of water to CHCl3 (2 l)). Sulfuric acid (167 ml) was added under stirring at 0° C. slowly. The upper CHCl3 layer was decanted, dried over anhydrous sodium sulfate, filtrated and kept in the refrigerator. Titration analysis was done before usage. The solution was added dropwise over a period of 8 h to a solution of cis-cyclohexane-1,3-dicarboxylic acid (50.0 g, 0.29 mol) in a mixture of sulfuric acid (150 ml) and CHCl3 (500 ml) at 35° C. After the completion of addition, the reaction mixture was stirred at 40° C. for 10 h and further stirred at 50° C. for 3 h. The reaction mixture was cooled to room temperature and the acid layer was separated. The acid layer was basified with barium hydroxide to pH˜9 and the suspension was filtered. The filtrate was neutralized with diluted sulfuric acid and the suspension was filtered again. The filtrate was concentrated under vacuo to get the crude compound which was washed with MeOH (30 ml) to get 39.0 g (93.8%) of cis-3-aminocyclohexanecarboxylic acid as solid. [TLC system: 15% MeOH in CHCl3, Rf 0.1].

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