Process for the preparation of enantiomeric forms of 2,3-diaminopropionic acid derivatives

1. A process for obtaining a compound of formula IV or a salt thereof:

wherein

R1 is a hydrogen atom, F, Cl, I, Br, (C 1 -C 4 )-alkyl or —CN;

R2 is a heteroaryl residue selected from the series consisting of pyrrole, furan, thiophene, imidazole, pyrazole, oxazole, isoxazole, thiazole, isothiazole, tetrazole, 1,2,3,5-oxathiadiazole-2-oxides, triazolones, oxadiazolone, isoxazolone, oxadiazolidinedione, triazole, 3-hydroxypyrrole-2,4-diones, 5-oxo-1,2,4-thiadiazoles, pyridine, pyrazine, pyrimidine, indole, isoindole, indazole, phthalazine, quinoline, isoquinoline, quinoxaline, quinazoline, cinnoline and β-carboline, wherein the heteroaryl residue is unsubstituted or is substituted once, twice or three times, independently of each other, by substituents selected from the series consisting of (C 1 -C 5 )-alkyl, (C 1 -C 5 )-alkoxy, halogen, nitro, amino, trifluoromethyl, hydroxy, hydroxy-(C 1 -C 4 )-alkyl-, methylenedioxy, ethylenedioxy, formyl, acetyl, cyano, hydroxycarbonyl-, aminocarbonyl- and (C 1 -C 4 )-alkoxycarbonyl-, or an aryl residue selected from the series consisting of phenyl, naphthyl, biphenylyl, anthryl and fluorenyl, wherein the aryl residue is unsubstituted or is substituted once, twice or three times, independently of each other, by substituents selected from the series consisting of (C 1 -C 5 )-alkyl, (C 1 -C 5 )-alkoxy, halogen, nitro, amino, trifluoromethyl, hydroxy, hydroxy-(C 1 -C 4 )-alkyl-, methylenedioxy, ethylenedioxy, formyl, acetyl, cyano, hydroxycarbonyl-, am inocarbonyl- and (C 1 -C 4 )-alkoxycarbonyl-;

R3 is a hydrogen atom,

or (C 1 -C 4 )-alkyl,

or an aryl residue selected from the series consisting of phenyl, naphthyl, biphenylyl, anthryl and fluorenyl, wherein the aryl residue is unsubstituted or is substituted, independently of each other, once, twice or three times by substituents selected from the series consisting of —NO 2 , —O—(C 1 -C 4 )-alkyl, F, Cl and Br,

or —O—C(CH 3 ) 3 ,

or —O—CH(R7)-aryl, wherein the aryl residue is selected from the series consisting of phenyl, naphthyl, biphenylyl, anthryl and fluorenyl and is unsubstituted or is substituted, independently of each other, once, twice or three times by substituents selected from the series consisting of —NO 2 , —O—CH 3 , F, Cl and Br, and wherein R7 is a hydrogen atom or (C 1 -C 4 )-alkyl; and

R5 is —NH 2 , —N(H)—R6 or —N(R6) 2 , wherein R6 is (C 1 -C 4 )-alkyl or aryl, wherein the aryl residue is selected from the series consisting of phenyl, naphthyl, biphenylyl, anthryl and fluorenyl;

said process comprising:

a) mixing a compound of formula II:

wherein R1, R2 and R3 are defined as in the compound of formula IV, in an organic solvent or a mixture of organic solvents with an enantiomerically pure auxiliary to form a salt composed of enantiomerically pure auxiliary and compound of formula I:

wherein R1, R2 and R3 are defined as in the compound of formula IV;

b) separating the salt composed of enantiomerically pure auxiliary and compound of formula I, by fractional crystallization;

c) isolating the compound of formula I from the salt composed of enantiomerically pure auxiliary and compound of formula I; and

d) converting the resulting compound of formula I with ammonia or an amine of the formula H 2 N—R6 or HN(R6) 2 , wherein R6 is (C 1 -C 4 )-alkyl or aryl, wherein the aryl residue is selected from the series consisting of phenyl, naphthyl, biphenylyl, anthryl and fluorenyl, into the compound of formula IV or a salt thereof.

2. The process as claimed in claim 1 , wherein the compound of formula IV or a salt thereof is obtained wherein

R1 is a hydrogen atom, F, Cl, I or Br;

R2 is phenyl, pyridinyl, pyrimidinyl or thiazolyl, wherein phenyl, pyridinyl, pyrimidinyl and thiazolyl are unsubstituted or substituted by fluorine or chlorine;

R3 is phenyl, methyl or —O—C(CH 3 ) 3 ;

R5 is —NH 2 , —N(H)—R6 or —N(R6) 2 , wherein R6 is (C 1 -C 4 )-alkyl or aryl, wherein the aryl residue is selected from the series consisting of phenyl, naphthyl, biphenylyl, anthryl and fluorenyl.

3. A compound of formula IV:

wherein

R1 is a hydrogen atom, F, Cl, I, Br, (C 1 -C 4 )-alkyl or —CN,

R2 is a heteroaryl residue selected from the series consisting of pyrrole, furan, thiophene, imidazole, pyrazole, oxazole, isoxazole, thiazole, isothiazole, tetrazole, 1,2,3,5-oxathiadiazole 2-oxides, triazolones, oxadiazolone, isoxazolone, oxadiazolidinedione, triazole, 3-hydroxypyrrole-2,4-diones, 5-oxo-1,2,4-thiadiazoles, pyridine, pyrazine, pyrimidine, indole, isoindole, indazole, phthalazine, quinoline, isoquinoline, quinoxaline, quinazoline, cinnoline and β-carboline, wherein the heteroaryl residue is unsubstituted or is substituted once, twice or three times, independently of each other, by substituents selected from the series consisting of (C 1 -C 5 )-alkyl, (C 1 -C 5 )-alkoxy, halogen, nitro, amino, trifluoromethyl, hydroxy, hydroxy-(C 1 -C 4 )-alkyl-, methylenedioxy, ethylenedioxy, formyl, acetyl, cyano, hydroxycarbonyl-, aminocarbonyl- and (C 1 -C 4 )-alkoxycarbonyl-, or an aryl residue selected from the series consisting of phenyl, naphthyl, biphenylyl, anthryl and fluorenyl, wherein the aryl residue is unsubstituted or is substituted once, twice or three times, independently of each other, by substituents selected from the series consisting of (C 1 -C 5 )-alkyl, (C 1 -C 5 )-alkoxy, halogen, nitro, amino, trifluoromethyl, hydroxy, hydroxy-(C 1 -C 4 )-alkyl-, methylenedioxy, ethylenedioxy, formyl, acetyl, cyano, hydroxycarbonyl-, am inocarbonyl- and (C 1 -C 4 )-alkoxycarbonyl-;

R3 is a hydrogen atom,

or (C 1 -C 4 )-alkyl,

or an aryl residue selected from the series consisting of phenyl, naphthyl, biphenylyl, anthryl and fluorenyl, wherein the aryl residue is unsubstituted or is substituted, independently of each other, once, twice or three times by substituents selected from the series consisting of —NO 2 , —O—(C 1 -C 4 )-alkyl, F, Cl and Br, or —O—C(CH 3 ) 3 ,

or —O—CH(R7)-aryl, wherein the aryl residue is selected from the series consisting of phenyl, naphthyl, biphenylyl, anthryl and fluorenyl and is unsubstituted or is substituted, independently of each other, once, twice or three times by substituents selected from the series consisting of —NO 2 , —O—CH 3 , F, Cl and Br, and wherein R7 is a hydrogen atom or (C 1 -C 4 )-alkyl; and

R5 is —NH 2 .

4. The process as claimed in claim 1 , wherein the compound of formula IV or a salt thereof is obtained wherein R5 is —NH 2 or —N(H)—R6, wherein R6 is (C 1 -C 4 )-alkyl or aryl, wherein the aryl residue is selected from the series consisting of phenyl, naphthylbiphenylyl, anthryl and fluorenyl.

5. The process as claimed in claim 1 , wherein the compound of formula IV or a salt thereof is obtained wherein R5 is —NH 2 .

6. The process as claimed in claim 1 , wherein the compound of formula IV or a salt thereof is obtained wherein R5 is —N(H)—R6 or —N(R6) 2 , and wherein R6 is (C 1 -C 4 )-alkyl.

7. The process as claimed in claim 1 , wherein the compound of formula IV or a salt thereof is obtained wherein R5 is —N(H)—R6 or —N(R6) 2 , and wherein R6 is methyl.

8. The compound as claimed in claim 3 , wherein R1 is a hydrogen atom, R2 is pyrimidinyl, and R3 is —O—C(CH 3 ) 3 .