PROCESS FOR PREPARING XPO1 INHIBITORS AND INTERMEDIATES FOR USE IN THE PREPARATION OF XP01 INHIBITORS

The present invention provides an improved process for preparation of the (Z)-3-(3-(3,5-bis(trifluoromethyl)phenyl)-1H-1,2,4-triazol-1-yl)acrylic acid (referred to as compound of the structural formula (III)), which is a useful key intermediate for the synthesis of Selinexor ((Z)-3-(3-(3,5-Bis(trifluoromethyl)phenyl)-1H-1,2,4-triazol-1-yl)-N-(pyrazin-2-yl)acrylohydrazide). The process comprises reaction of the compound of the structural formula (I) (as described herein) with the compound of the structural formula (II) (as described herein) in the presence of a catalyst, an organic base and an ether-containing solvent. The subsequent hydrolysis of the formed compound of the structural formula (IIIa) (as described herein) is performed without isolation of the compound of the structural formula (IIIa), providing compound of the structural formula (III) in high yield and stereoselectivity.