Hydrochloric Acid → (1r,2s,4r)-2-Hydroxy-4-methylcyclohexanecarboxylic acid

Temperature

12.5 °C

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).

1. extractionextracted with DCM
2. extractionThe combined organic extract
3. washwas washed with brine
4. customdried
5. concentrationconcentrated

ORD record

ord-d547b3723cf54595a2a09ef1f96e45e4

Source dataset

uspto-grants-2008_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07402608B2