Process for preparing XPO1 inhibitors and intermediates for use in the preparation of XPO1 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.
1 . A process of making a compound represented by structural formula III,
the process comprising:
reacting a compound represented by structural formula (I) with a compound represented by structural formula (II),
in the presence of a catalyst 1,4-diazabicyclo[2.2.2]octane (DABCO), an organic base selected from Et3N, diisopropylethyamine (DIPEA), piperidine, pyridine, and 4-dimethylaminopyridine (DMAP), and an ether-containing solvent selected from cyclopentyl methyl ether (CPME), methyl tert-butyl ether (MTBE), and methyltetrahydrofuran (MeTHF) under the conditions suitable to produce a compound represented by structural formula (IIIa),
and
wherein the catalyst is present in an amount from 0.05 to 0.2 molar equivalents based on the amount of the compound represented by structural formula I;
without isolating, reacting the compound represented by structural formula (IIIa) with an inorganic base in the presence of isopropyl alcohol (IPA) under conditions suitable to produce a compound represented by structural formula (III);
wherein the inorganic base is a metal hydroxide selected from LiOH, NaOH, and KOH; and
isolating the compound represented by structural formula (III), wherein R is a C 2 -C 5 alkyl or a C 6 -C 18 aryl.
2 . The process of claim 1 , wherein R is isopropyl or a phenyl.
3 . The process of claim 1 , wherein the catalyst and the organic base are present in a combined amount of less than 1 molar equivalent of the compound represented by structural formula II.
4 . The process of claim 1 , wherein the catalyst is present in an amount of 0.1 molar equivalents based on the amount of the compound represented by structural formula I.
5 . The process of claim 1 , wherein the organic base is present in the amount from 0.5 to 2 molar equivalents based on the amount of the compound represented by structural formula I.
6 . The process of claim 1 , wherein the organic base is present in the amount of 1.0 molar equivalents based on the amount of the compound represented by structural formula I.
7 . The process of claim 1 , wherein the amount of the compound of structural formula II is from 1.0 to 1.5 molar equivalents based on the amount of compound of structural formula I.
8 . The process of claim 1 , wherein the conditions suitable to produce the compound represented by structural formula IIIa include reacting the compound represented by structural formula I with the compound represented by structural formula II at a temperature from 5° C. to 55° C.
9 . The process of claim 1 , wherein the conditions suitable to produce the compound represented by structural formula III include reacting the compound represented by structural formula IIIa with an inorganic base at a temperature from 5° C. to 55° C.
10 . The process of claim 1 , further including isolating the compound represented by structural formula III from a reaction mixture.
11 . The process of claim 10 , wherein isolating the compound represented by structural formula III comprises:
(i) adding water and HCl to the the reaction mixture comprising the compound represented by structural formula III, thereby generating an aqueous phase and an organic phase;
(ii) separating and, optionally, concentrating the organic phase, thereby generating a final organic phase;
(iii) adding a C 5 -C 12 hydrocarbon solvent to the final organic phase, thereby generating a precipitate of the compound represented by structural formula III; and
(iv) isolating the precipitate of the compound represented by structural formula III.
12 . The process of claim 11 , wherein the C 5 -C 12 hydrocarbon solvent is heptane or isooctane.