Methods for the preparation of charged crosslinkers
Processes for the preparation of charged crosslinkers bearing a sulfonic acid moiety are disclosed. These procedures also optionally include methods to convert the resulting products to substantially a single salt form.
1. A process for the preparation of a compound of formula (III):
or a salt thereof, comprising the step of reacting a compound of formula (II):
or a salt thereof, with a sulfonating agent in the presence of a base, wherein:
Q represents a disulfide group selected from alkyl disulfide, phenyl disulfide, ortho or para-nitrophenyl disulfide, 2,4-dintrophenyl disulfide, pyridyl disulfide, nitropyridyl disulfide; a maleimido group or a haloacetyl group;
G and F are both absent;
E represents a linear or branched alkyl bearing 1 to 4 carbon atoms; and
R 1 is —H or a linear, branched or cyclic alkyl, alkenyl or alkynyl bearing 1 to 10 carbon atoms.
2. The process of claim 1 , wherein the sulfonating agent is chlorosulfonic acid or sulfur trioxide; and the base is triethyl amine, diisopropylethyl amine or tributyl amine.
3. The process of claim 1 , wherein the sulfonating agent is chlorosulfonic acid and the base is diisopropylethyl amine.
4. The process of claim 1 , wherein E is —CH 2 —CH 2 — and R 1 is H.
5. The process of claim 1 , wherein Q is pyridyl disulfide.
6. A process for the preparation of a compound of formula (IV):
or a salt thereof, comprising the step of reacting a compound of formula (2a):
or a salt thereof, with a sulfonating agent in the presence of a base.
7. The process of claim 6 , wherein the sulfonating agent is chlorosulfonic acid or sulfur trioxide and the base is triethyl amine, diisopropylethyl amine or tributyl amine.
8. The process of claim 6 , wherein the sulfonating agent is chlorosulfonic acid and the base is diisopropylethyl amine.
9. The process of claim 8 , wherein the sulfonating reaction is carried out in the presence of 1,2-di(pyridin-2-yl)disulfane (PySSPy).
10. The process of claim 9 , wherein about 0.5 equivalent of PySSPy is present.
11. The process of claim 6 , wherein the process further comprises the step of purifying the compound of formula (IV) obtained by the reaction.
12. The process of claim 11 , wherein the compound of formula (IV) is purified by reverse phase chromatography using a silica column.
13. The process of claim 1 , further comprising reacting the compound of formula (III) or a salt thereof with a hydroxy or mercapto compound to form a compound of formula (I),
or a salt thereof, wherein:
C(═O)L represents a reactive ester or thioester group selected from N-hydroxysuccinimide ester, N-hydroxy sulfosuccinimide ester, nitrophenyl ester, tetrafluoro phenyl ester, pentafluorophenyl ester, a thiopyridyl ester and a thionitrophenyl ester.
14. The process of claim 13 , wherein the reaction between the compound of formula (III) and the hydroxy or mercapto compound is carried out in the presence of a coupling agent selected from N,N′-dicyclohexylcarbodiimide (DCC), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), N,N′-diisopropyl carbodiimide (DIC) and 1-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ).
15. The process of claim 14 , wherein the coupling agent is EDC.
16. The process of claim 13 , wherein the reactive ester is N-hydroxysuccinimide ester.
17. The process of claim 13 , wherein E is —CH 2 —CH 2 — and R 1 is H.
18. The process of claim 13 , wherein Q is pyridyl disulfide.
19. A process for the preparation of a compound represented by formula (V):
or a salt thereof, comprising the steps of:
a) reacting a compound of formula (2a):
or a salt thereof, with a sulfonating agent in the presence of a base to form a compound of formula (IV):
or a salt thereof; and
b) reacting the compound of formula (IV), or a salt thereof, with N-hydroxysuccinimide to form the compound of formula (V).
20. The process of claim 19 , wherein the sulfonating agent is chlorosulfonic acid or sulfur trioxide and the base is the base is triethyl amine, diisopropylethyl amine or tributyl amine.
21. The process of claim 19 , wherein the sulfonating agent is chlorosulfonic acid and the base is diisopropylethyl amine.
22. The process of claim 21 , wherein the sulfonating reaction is carried out in the presence of PySSPy.
23. The process of claim 22 , wherein about 0.5 equivalent of PySSPy is present.
24. The process of claim 19 , wherein the reaction between the compound of formula (IV) and N-hydroxysuccinimide is carried out in the presence of a coupling agent selected from N,N′-dicyclohexylcarbodiimide (DCC), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), N,N′-diisopropyl carbodiimide (DIC) and 1-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ).
25. The process of claim 24 , wherein the coupling agent is EDC.
26. The process of claim 19 , wherein the reaction between the compound of formula (IV) and N-hydroxysuccinimide is carried in the presence of a base.
27. The process of claim 26 , wherein the base is diisopropylethylamine (DIPEA).
28. The process of claim 19 , wherein the process comprises the steps of:
a) reacting the compound of formula (2a) or a salt thereof with chlorosulfonic acid to form the compound of formula (IV); and
b) reacting the compound of formula (IV) with N-hydroxysuccinimide in the presence of EDC to form the compound of formula (V).
29. The process of claim 19 , further comprising the step of purifying the compound of formula (IV) or a salt thereof.
30. The process of claim 29 , wherein the compound of formula (IV) or a salt thereof is purified by reverse phase chromatography using a silica column.
31. The process of claim 28 , further comprising the step of purifying the compound of formula (V) or a salt thereof.
32. The process of claim 31 , wherein the compound of formula (V) or a salt thereof is purified by reverse phase chromatography using a silica column.
33. The process of claim 31 , wherein the compound of formula (V) or a salt thereof is purified by crystallization.