Potassium Hydroxide → 1-Carbethoxy-4-methylamino-3-ethylpiperidine

Temperature

0 °C

Methylamine hydrochloride (17 g, 252 mmol) was added to the stirred solution of 1-carbethoxy-3-ethyl-4-piperidone (10 g, 50 mmol) in methanol (150 ml) followed by 14.1 g (252 mmol) KOH. Stirring was continued for 3 hr at ambient temperature. The resulting mixture was cooled at 0° C. and sodium cyanoborohydride (4.72 g, 75 mmol) was added to it. Cooling was removed after 10 min. and resulting mixture was stirred for 12 hr at ambient temperature. The reaction mixture was concentrated to dryness, triturated with water, acidified with conc. HCl (pH 3˜4) and extracted with ethyl acetate to remove impurities. The aqueous layer was basified with 1 M sodium hydroxide solution (pH˜10) and extracted with ethyl acetate. Ethyl acetate extract was dried (Na2SO4) and concentrated to dryness to give crude 1-carbethoxy-4-methylamino-3-ethylpiperidine. The obtained crude 1-carbethoxy-4-methylamino-3-ethylpiperidine was suspended in 7 M NaOH solution (50 ml), stirred at 110° C. for 230 hr, cooled, extracted with ethyl acetate, dried (Na2SO4) and concentrated to dryness to afford 4-methylamino-3-ethyl-piperidine. Yield 3.5 g (50%), C8H18N2, m/z 142 (M+1).

1. temperatureCooling
2. customwas removed after 10 min.
3. customresulting mixture
4. stirringwas stirred for 12 hr at ambient temperature
5. concentrationThe reaction mixture was concentrated to dryness
6. customtriturated with water
7. extractionextracted with ethyl acetate
8. customto remove impurities
9. extractionextracted with ethyl acetate
10. extractionEthyl acetate extract
11. dry with materialwas dried (Na2SO4)
12. concentrationconcentrated to dryness

ORD record

ord-aaeb46f62e9e4a0cb0f4c785943c25d7

Source dataset

uspto-grants-2009_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07626032B2