Synthesis of diamido gellants by using amino acid N-carboxyanhydrides
The invention relates to a method for the synthesis of a compound according to formula I comprising the following steps: a) reacting a N-carboxyanhydride according to formula II and a N-carboxy-anhydride according to formula III with a diamine according to formula IV and b) adding an acid to the reaction to adjust the pH value of the reaction to <7; wherein L represents a C 2 -C 20 alkyl group, a C 6 -C 20 aryl group, or a C 7 -C 20 alkylaryl group; and R 1 and R 2 can be identical or different and represent a hydrogen atom, a C 1 -C 4 alkyl group, a C 1 -C 4 hydroxyalkyl group, a C 1 -C 4 thioether group, a C 6 -C 20 aryl group, a C 7 -C 20 alkylaryl group, a C 7 -C 20 alkylhydroxyaryl group, a C 4 -C 20 alkylheteroaryl group with 1 to 4 heteroatoms; or a C 1 -C 4 alkylcarboxylic moiety, which may be an acid, an amide, or which may be esterified with a C 1 -C 6 alkyl group or a C 7 -C 20 alkylaryl group.
1. Method for the synthesis of a compound according to formula I
comprising the following steps:
a) reacting a N-carboxyanhydride according to formula II
and a N-carboxyanhydride according to formula III
with a diamine according to formula IV
and
b) adding an acid to the reaction to adjust the pH value of the reaction to <7;
wherein
L represents a C 2 -C 20 alkyl group, a C 6 -C 20 aryl group, or a C 7 -C 20 alkylaryl group; and
R 1 and R 2 can be identical or different and represent a hydrogen atom, a C 1 -C 4 alkyl group, a C 1 -C 4 hydroxyalkyl group, a C 1 -C 4 thioether group, a C 6 -C 20 aryl group, a C 7 -C 20 alkylaryl group, a C 7 -C 20 alkylhydroxyaryl group, or a C 4 -C 20 alkylheteroaryl group with 1 to 4 heteroatoms;
or a C 1 -C 4 alkylcarboxylic moiety, which may be an acid, an amide, or which may be esterified with a C 1 -C 6 alkyl group or a C 7 -C 20 alkylaryl group.
2. Method according to claim 1 , wherein R 1 and R 2 can be identical or different and represent a hydrogen atom, a n-butyl group, a t-butyl group, a propyl group, a cyclopropyl group, an ethyl group, or one of the side chains of the amino acids alanine, valine, leucine, isoleucine, methionine, phenylalanine, tyrosine, tryptophan, serine, threonine, glutamine, asparagine, esters of glutamic acid, or esters of aspartic acid.
3. Method according to claim 1 , wherein L represents a C 6 -C 12 linear alkyl group, a 1,4-dimethylcyclohexyl group, or a xylene group.
4. Method according to claim 1 , wherein in step b) the pH value is adjusted to 1 to 2.
5. Method according to claim 1 , wherein mixing of the reactants in step a) is carried out at a temperature of −10 to +30° C.
6. Method according to claim 1 , wherein in step a) the N-carboxyanhydrides according to formulae II and III are provided in an initial total molar amount that is 2 to 3.5-fold higher than the initial molar amount of the diamine.
7. Method according to claim 1 , wherein the reaction in step a) is carried out in a polar aprotic solvent.
8. Method according to claim 7 , wherein the solvent is selected from the group consisting of dichloromethane, methyl tert-butyl ether, tetrahydrofuran, ethyl acetate, isopropyl acetate, dimethylformamide, acetonitrile, dimethylsulfoxide, methyl isobutyl ketone, methyl ethyl ketone, acetone or mixtures thereof.
9. Method according to- claim 2 , wherein L represents a C 6 -C 12 linear alkyl group, a 1,4-dimethylcyclohexyl group, or a xylene group.
10. Method according to claim 2 , wherein in step b) the pH value is adjusted to 1 to 2.
11. Method according to claim 3 , wherein in step b) the pH value is adjusted to 1 to 2.
12. Method according to claim 2 , wherein mixing of the reactants in step a) is carried out at a temperature of −10 to +30° C.
13. Method according to claim 3 , wherein mixing of the reactants in step a) is carried out at a temperature of −10 to +30° C.
14. Method according to claim 4 , wherein mixing of the reactants in step a) is carried out at a temperature of −10 to +30° C.
15. Method according to claim 2 , wherein in step a) the N-carboxyanhydrides according to formulae II and III are provided in an initial total molar amount that is 2 to 3.5-fold higher than the initial molar amount of the diamine.
16. Method according to claim 3 , wherein in step a) the N-carboxyanhydrides according to formulae II and III are provided in an initial total molar amount that is 2 to 3.5-fold higher than the initial molar amount of the diamine.
17. Method according to claim 4 , wherein in step a) the N-carboxyanhydrides according to formulae II and III are provided in an initial total molar amount that is 2 to 3.5-fold higher than the initial molar amount of the diamine.
18. Method according to claim 5 , wherein in step a) the N-carboxyanhydrides according to formulae II and III are provided in an initial total molar amount that is 2 to 3.5-fold higher than the initial molar amount of the diamine.
19. Method according to claim 2 , wherein the reaction in step a) is carried out in a polar aprotic solvent.
20. Method according to claim 3 , wherein the reaction in step a) is carried out in a polar aprotic solvent.