PROCESS FOR PREPARING CARBOXAMIDE PYRIDINE DERIVATIVES USED AS INTERMEDIATES IN THE SYNTHESIS OF NK-1 RECEPTOR ANTAGONISTS

摘要

The present invention proides a process for preparing a pyridine compound of formula (I), where R1, R2, R3 and a are those defined herein. These compounds may be used as intermediates for the preparation of pharmaceutically active NK-1 receptor antagonists.