Claims
- 1. A process for the preparation of a compound of formula (I) in optically active form with absolute configuration (S) where Y is OH; X− is NO3−or a compound of formula (I) in the form of an inner salt of the formula (II) and their enantiomerically enriched mixtures, comprising treating a formula (III) compound with a nitrating agent not involving the formation of a bond with the asymmetric carbon atom according to the following scheme: where T is an hydroxy group, X1−, equal to or different from X− to yield the formula (I) compound with the same absolute configuration as the formula (III) compound.
- 2. The process according to claim 1, in which said nitrating agent is a mixture of nitric acid, and acetic anhydride or a mixture of nitric acid, acetic acid and acetic anhydride.
- 3. The process according to claim 1, in which the X− group, if required, may be varied subsequent to treatment with the nitrating system.
- 4. The process according to claim 3, in which the variation of the X− group is done by ion-exchange resins or electrodialysis.
- 5. The method according to claim 1, in which an enantiomerically enriched mixture comprises a content of (S) enantiomer higher than 95%.
- 6. A process for the preparation of (R)-carnitine starting from the corresponding enantiomer (S) of a compoundof formula (I) in optically active form with absolute configuration (S) where Y is OH; X− is NO3−or a compound of formula (I) in the form of an inner salt of the formula (II) and their enantiomerically enriched mixtures comprising treating said compound with a diluted base.
- 7. The process according to claim 6, where said diluted base is sodium bicarbonate.
- 8. The process according to claim 6, where said base is diluted in water or in mixtures of water and organic solvent mixable with water.
- 9. The process according to claim 6, where the pH ranges from 7 to 10.
- 10. The process according to claim 6, where the reaction temperature ranges from 50 to 100° C.
- 11. A process for the preparation of (R)-carnitine, comprising the following steps:a) treatment of a formula (III) enantiomer of absolute configuration (S), of claim 1, with a nitrating agent not involving the formation of a bond with the asymmetric carbon atom, to yield the formula (I) compound with the same absolute configuration as the formula (III) compound; and b) treatment of the formula (I) compound with diluted bases.
- 12. The process according to claim 11, carried out without isolation of the formula (I) compound.
- 13. A process for the preparation of (R)-carnitine from (S)-carnitine comprising transformation of the formula (I) compound in which Y═OR or NR1R2, with R═H, C1-C10 alkyl, or substituted alkyl and where R1R2, equal or different from one another, are hydrogen, C1-C10 alkyl and X−═NO3−, into the formula (IV) compound, enantiomerically enriched of, respectively, absolute configuration (R): with organic or inorganic bases in water or water and organic solvent mixable with water.
Priority Claims (1)
Number |
Date |
Country |
Kind |
RM99A0508 |
Aug 1999 |
IT |
|
Parent Case Info
This application is a divisional of Ser. No. 09/804,270 filed Mar. 13, 2001, now U.S. Pat. No. 6,395,923, which is a continuation of PCT/IT00/00325 filed Jul. 31, 2000.
US Referenced Citations (5)
Number |
Name |
Date |
Kind |
3830931 |
De Felice |
Aug 1974 |
A |
5214166 |
Manser et al. |
May 1993 |
A |
5227513 |
Meul |
Jul 1993 |
A |
5532410 |
Giannessi et al. |
Jul 1996 |
A |
6365611 |
Konig et al. |
Apr 2002 |
B1 |
Foreign Referenced Citations (5)
Number |
Date |
Country |
9856759 |
Jun 1998 |
DE |
WO9856759 |
Dec 1998 |
DE |
0 609 643 |
Aug 1994 |
EP |
0 624 568 |
Nov 1994 |
EP |
0 636 603 |
Feb 1995 |
EP |
Continuations (1)
|
Number |
Date |
Country |
Parent |
PCT/IT00/00325 |
Jul 2000 |
US |
Child |
09/804270 |
|
US |