Sulfuric Acid → (S)-2-Methoxycyclohexanone

Beteiligte Stoffe

Reaktionsschritte

Reaction was carried out in the same manner as in Example 16. After the peak due to (S)-2)-methoxycyclohexanol had disappeared, the reaction solution was given 2 g of sodium hydrogensulfite with stirring so that the reaction solution did not change potassium iodide starch paper into purple any longer. The reaction solution was adjusted to pH 2 or below with 10% sulfuric acid, followed by stirring at 20-25° C. for 1 hour. The reaction solution was adjusted to pH 7.5-8 with an aqueous solution of sodium carbonate, followed by stirring at 20-25° C. for 1 hour. The reaction solution was adjusted again to pH 2 or below with 10% sulfuric acid, followed by stirring at 20-25° C. for 2 hours. The reaction solution was extracted three times with 100 g of toluene. The toluene layers were combined together and washed with a saturated aqueous solution of sodium chloride. After concentration and distillation in the same manner as in Example 1, there was obtained 10.3 g (80 mmol) of (S)-2-methoxycyclohexanone having a chemical purity of 99.3% and an optical purity of 99.6% ee. This product was heated at 60° C. for 48 hours in the same manner as in Example 16; it decreased in optical purity to 99.0% ee.

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