Method for purifying 2,2,6,6,-tetrasubstituted 4-aminopiperidines with hydrogen in the presence of a hydrogenation or dehydrogenation catalyst

摘要

A method for purifying 2,2,6,6-tetrasubstituted 4-amino-piperidines (Formula I) produced from the corresponding piperidin-4-ones (Formula II), and subsequent distillation. The distilled 2,2,6,6-tetrasubstituted 4-amino-piperidine is reacted with hydrogen in the presence of a hydrating or dehydrating catalyst and the 4-amino piperidine is then separated from the reaction mixture. Wherein; R1 to R4 is C1-6alkyl, R1-R2 and/or R3 and R4 together form a CH2 chain having from 2-5 carbon atoms.