Synthesis of diamido gellants by using Dane salts of amino acids
The invention relates to a method for the synthesis of a compound according to formula I comprising the following steps: a) reacting a Dane salt according to formula II and a Dane salt according to formula III with a coupling reagent; b) adding a diamine according to formula IV to the reaction mixture; and c) adding an acid to the reaction mixture 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; 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; R 3 represents a C 1 -C 4 alkyl group; R 4 represents a hydrogen atom, or a C 1 -C 4 alkyl group; R 5 represents a C 1 -C 4 alkyl group; and X represents an alkali metal.
1. Method for the synthesis of a compound according to formula I
comprising the following steps:
a) reacting a Dane salt according to formula II
and a Dane salt according to formula III
with a coupling reagent;
b) adding a diamine according to formula IV
to the reaction mixture; and
c) adding an acid to the reaction mixture 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;
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;
R 3 represents a C 1 -C 4 alkyl group;
R 4 represents a hydrogen atom, or a C 1 -C 4 alkyl group;
R 5 represents a C 1 -C 4 alkyl group; and
X represents an alkali metal.
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 R 3 represents a methyl group.
5. Method according to claim 1 , wherein R 4 represents a hydrogen atom.
6. Method according to claim 1 , wherein R 5 represents a methyl or ethyl group.
7. Method according to claim 1 , wherein X is Na or K.
8. Method according to claim 1 , wherein R 3 and R 4 in formulae II and III have a cis configuration with respect to each other.
9. Method according to claim 1 , wherein the coupling reagent is selected from the group consisting of pivaloylchloride, mesylchloride, biphenylphosphorylchloride or isobutylchloroformate or a mixture thereof.
10. Method according to claim 1 , wherein in step c) the pH value is adjusted to pH 1-2.
11. Method according to claim 1 , wherein the reaction in step a) is carried out at a temperature of −10 to +30° C.
12. Method according to claim 1 , wherein the reaction in steps a) and b) is carried out in a polar aprotic solvent.
13. Method according to claim 12 , 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.
14. 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.
15. Method according to claim 2 , wherein R 3 represents a methyl group.
16. Method according to claim 3 , wherein R 3 represents a methyl group.
17. Method according to claim 2 , wherein R 4 represents a hydrogen atom.
18. Method according to claim 3 , wherein R 4 represents a hydrogen atom.
19. Method according to claim 4 , wherein R 4 represents a hydrogen atom.
20. Method according to claim 2 , wherein R 5 represents a methyl or ethyl group.