Trifluoroacetic acid → Ethyl 4-amino-1-benzylpiperidine-3-carboxylate

Temperature

50 °C

Amino-1-benzyl-1,2,5,6-tetrahydro-pyridine-3-carboxylic acid methyl ester BH3 salt was heated in ethanol with NaOH 25%. After 72 h at 50° C. the mixture was cooled, washed with water/ice and extracted with AcOEt. The extract was washed with brine and dried over sodium sulfate. Removal of the solvent under reduced pressure gave an yellow oil. To a suspension of 4-amino-1-benzyl-1,2,5,6-tetrahydro-pyridine-3-carboxylic acid methyl ester (21 g) in 200 ml THF was added 50 ml TFA at 10° C. under an argon atmosphere. After stirring for 15 min at 0° C., NaBH4 (6.43 g) was added over a period of 75 min at 10° C. The mixture was stirred for additional 90 min at 0° C. After adding 100 ml NH4Cl saturated, the solution was extracted two times with CH2Cl2. The combined extracts were washed with water/ice and brine and dried over sodium sulfate. Evaporation of the solvent gave a yellow oil of the title compound which was taken for the next step without purification

1. washwashed with water/ice
2. extractionextracted with AcOEt
3. washThe extract was washed with brine
4. dry with materialdried over sodium sulfate
5. customRemoval of the solvent under reduced pressure
6. customgave an yellow oil
7. stirringThe mixture was stirred for additional 90 min at 0° C
8. extractionthe solution was extracted two times with CH2Cl2
9. washThe combined extracts were washed with water/ice and brine
10. dry with materialdried over sodium sulfate
11. customEvaporation of the solvent

ORD record

ord-bbb081a7f64643799cfa87f676836767

Source dataset

uspto-grants-2010_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07683079B2