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

Participants

Reaction Conditions

Reaction Steps

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

Provenance & Evidence