Sulfuric Acid → 1-(2-Ethyl-butyl)-cyclohexanecarboxylic acid

Temperature

160 °C

1-(2-Ethyl-butyl)-cyclohexanecarboxylic acid isopropyl ester (3.0 g, 11.8 mmol) was dissolved in ethylene glycol (48 mL). Powdered KOH (6.0 g, 107 mmol) was added and the mixture was stirred 42 h at 160° C. The cooled reaction mixture was slowly added to a stirred mixture of ice-water (120 mL) and 4M H2SO4 (40 mL), and extracted with DCM (2×120 mL). The organic phases were washed with diluted aq. NaCl until neutral, combined, dried over sodium sulfate and concentrated. The residue (2.5 g) was taken up in 4N NaOH and ice (30 g). The alkaline solution (pH 12) was extracted with TBME (40 mL). The TBME phase was washed twice with 4N NaOH/ice. The basic aqueous phases were made acidic to pH 1 using aq. H2SO4. Extraction with DCM (2×50 mL), washing with diluted aq. NaCl, drying over sodium sulfate and evaporation afforded 1.5 g (60%) 1-(2-ethyl-butyl)-cyclohexanecarboxylic acid, purity 94.1% (GC area, after derivatization with diazomethane).

1. customThe cooled reaction mixture
2. extractionextracted with DCM (2×120 mL)
3. washThe organic phases were washed with diluted aq. NaCl until neutral,
4. dry with materialdried over sodium sulfate
5. concentrationconcentrated
6. extractionThe alkaline solution (pH 12) was extracted with TBME (40 mL)
7. washThe TBME phase was washed twice with 4N NaOH/ice
8. extractionExtraction with DCM (2×50 mL)
9. washwashing with diluted aq. NaCl
10. dry with materialdrying over sodium sulfate and evaporation

ORD record

ord-4e9595da15734b4abbb581707356a8ed

Source dataset

uspto-grants-2011_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08071803B2