PROCESS FOR PREPARING A PYRIMIDINE INTERMEDIATE

摘要

The present invention relates to a process for preparing a pyrimidine intermediate, namely the compound of formula I-2 or a salt thereof. Said compound of formula I-2 or its salt can be used to prepare macitentan. Macitentan (chemical names: N-[5-(4-bromophenyl)-6-[2-[(5-bromo-2-pyrimidinyl)oxy]ethoxy]-4-pyrimidinyl]-N′-propylsulfamide or N-[5-(4-bromophenyl)-6-{2-[(5-bromopyrimidin-2-yl)oxy]ethoxy}pyrimidin-4-yl]-N′-propylsulfuric diamide) is an endothelin receptor antagonist that has notably been approved by the US Food and Drug Administration and the European Commission for the treatment of pulmonary arterial hypertension. It has been first disclosed in WO 02/053557. The last step of one of the potential preparation routes described in WO 02/053557, called “Possibility A” and “Possibility B”, can be summarised as shown in Scheme A1 hereafter.