Pyridine → (1R,2S,4R)-2-Acetoxy-4-methyl-cyclohexanecarboxylic acid

To a solution of (1R,2S,4R)-2-Hydroxy-4-methyl-cyclohexanecarboxylic acid (162 mg, 1.02 mmol) in dichloromethane (5 ml) was added pyridine (495 ul, 6.12 mmol) followed by acetic anhydride (385 ul, 4.08 mmol). The reaction mixture was stirred for 20 h at room temperature. Then, the solvents were removed and 10 ml of 3N HCl solution was added. This mixture was stirred for 30 minutes and then a saturated solution of NaHCO3 was slowly added until pH=9-10. This solution was then extracted with ethyl acetate (2×5 ml). The aqueous phase was then acidified with a 10% HCl solution and extracted with ethyl acetate (3×5 ml). The following ethyl acetate layers were combined, dried (Na2SO4) and concentrated to obtain 109 mg (53%) of (1R,2S,4R)-2-Acetoxy-4-methyl-cyclohexanecarboxylic acid. NMR 1H (CDCl3, 400 MHz): 5.45 ppm (s, 1H); 2.46-2.42 ppm (m, 1H); 2.02 ppm (s, 3H); 2.02-1.96 ppm (m, 1H); 1.91-1.76 ppm (m, 3H); 1.70-1.61 ppm (m, 1H); 1.16-1.08 ppm (m, 1H); 0.99-0.88 ppm (m, 1H); 0.87 ppm (d, 3H).

1. customThen, the solvents were removed
2. addition10 ml of 3N HCl solution was added
3. stirringThis mixture was stirred for 30 minutes
4. additiona saturated solution of NaHCO3 was slowly added until pH=9-10
5. extractionThis solution was then extracted with ethyl acetate (2×5 ml)
6. extractionextracted with ethyl acetate (3×5 ml)
7. dry with materialdried (Na2SO4)
8. concentrationconcentrated

ORD-Eintrag

ord-eaa20f59634042ab9a9bf8bb476db6b9

Quelldatensatz

uspto-grants-2011_07

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07985769B2