Hydrochloric Acid → HCID 44548658, Verbindung

Temperatur

0 °C

To a solution of dicyclohexylamine (4.281 g, 23.6 mmol) in THF (27 mL) 1.6 M n-BuLi in hexane (13.22 mL, 21.14 mmol) was added with stirring over 50 min at temperature between −20° C. and −15° C. The orange suspension was stirred 10 min at −20° C. and then warmed up to 0° C. To this suspension a solution of cyclohexanecarboxylic acid n-propyl ester (3.0 g, 17.62 mmol) in THF (9 mL) was added over 15 min at 0° C. The resulting solution was stirred 30 min at 0° C., then 1-bromo-2-ethylbutane (4.072 g, 24.67 mmol) in THF (11.25 mL) was added at the same temperature over 15 min. Stirring was continued 5 h at 0° C. and overnight at room temperature. At 5° C. cold water (25 mL) was added, followed by 2N HCl (60 mL). The white suspension was filtered and the filter cake was washed with water and ethyl acetate. The organic phase of the filtrate was washed with sat. aq. NaHCO3 and with aq. NaCl. The aqueous phases were extracted with ethyl acetate. The organic phases were combined, dried over sodium sulfate and concentrated. The crude product (5.1 g) was distilled at 60° C. (0.05 mbar) to give 3.47 g (77%) 1-(2-ethyl-butyl)-cyclohexanecarboxylic acid n-propyl ester as a colorless oil, purity 97% (GC area). 1H-NMR (CDCl3, 400 MHz): ppm 0.79 (t, 6H), 0.96 (t, 3H), 1.15-1.42 (m, 10H), 1.41-1.43 (m, 2H), 1.52-1.61 (m, 3H), 1.63-1.70 (m, 2H), 2.06-2.14 (m, 2H), 4.0 (t, 2H).

1. stirringThe orange suspension was stirred 10 min at −20° C.
2. stirringThe resulting solution was stirred 30 min at 0° C.
3. stirringStirring
4. waitwas continued 5 h at 0° C. and overnight at room temperature
5. filtrationThe white suspension was filtered
6. washthe filter cake was washed with water and ethyl acetate
7. washThe organic phase of the filtrate was washed with sat. aq. NaHCO3 and with aq. NaCl
8. extractionThe aqueous phases were extracted with ethyl acetate
9. dry with materialdried over sodium sulfate
10. concentrationconcentrated
11. distillationThe crude product (5.1 g) was distilled at 60° C. (0.05 mbar)

ORD-Eintrag

ord-484b3161a6b44ce9ae47b0ad0f937d52

Quelldatensatz

uspto-grants-2011_12

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08071803B2