Reaktion #160379

Reaktionsgleichung

NaOBr

(1R,2S,4R)-1-(2-Hydroxy-4-methyl-cyclohexyl)-ethanone

NaOBr

Na2SO3

HCl

NaOH

bromine

→

(1R,2S,4R)-2-hydroxy-4-methyl-cyclohexanecarboxylic acid

Ausbeute 94.2%

Lösungsmittel

dioxane

water

water

1,4-dioxane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Extraktionextracted with DCM
2. 2
   ExtraktionThe combined organic extract
3. 3
   Waschenwas washed with brine
4. 4
   Sonstigedried
5. 5
   Einengenconcentrated

Vorschrift

To a ice-cold solution of NaOH (4.8 g, 119.2 mmol) in water (40 mL) and 1,4-dioxane (30 mL) was added bromine (1.5 mL, 29.57 mmol). To the resultant NaOBr yellow solution was added drop wise a solution (1R,2S,4R)-1-(2-Hydroxy-4-methyl-cyclohexyl)-ethanone (1.4 g, 8.962 mmol) in dioxane (130 mL) and water (35 mL). The resulting solution was stirred for 3 h at 10-15° C. The excess NaOBr solution was decomposed by adding a solution of Na2SO3 (1.1 g in 11 mL water), acidified with 10% HCl, extracted with DCM. The combined organic extract was washed with brine, dried and concentrated to give (1R,2S,4R)-2-hydroxy-4-methyl-cyclohexanecarboxylic acid (1.30 g, 92%). NMR 1H (CDCl3, 400 MHz): 4.34 ppm (s, 1H); 2.43-2.39 ppm (m, 1H); 1.96-1.76 ppm (m, 5H); 1.14-1.08 ppm (m, 1H); 1.02-0.93 ppm (m, 1H); 0.90 ppm (d, 3H).

Quelle