PROCESS FOR THE PREPARATION OF OPTICALLY ENRICHED 4-ARYL-3-HYDROMETHYL SUBSTITUTED PIPERIDINES TO BE USED AS INTERMEDIATES IN THE SYNTHESIS OF PAROXETINE

摘要

For the preparation of anti-depressants such as paroxetine, novel intermediates are optically-enriched compounds of formula (1), wherein Ar is a C6-20 aryl group; and R?1 and R2¿ are independently H, alkyl or aryl. These compounds may be prepared by reduction of the corresponding 1,4-dihydropyridine-3-aldehyde, e.g. using hydrogen and a catalyst. The aldehyde may be prepared by hydrolytic cleavage of an aminal obtainable by the reaction of 3-pyridinecarboxaldehyde and a chiral C-2 symmetric diamine, and then stereoselective introduction of the Ar and COCHR1R2 groups.