Claims
- 1. A process for preparing an optically active carnitine ester represented by formula (I): wherein R represents a lower alkyl group having two or more carbon atoms; and X represents a halogen atom,which process consists essentially of asymmetrically hydrogenating a γ-trimethylammonium-3-oxabutanoic ester halide represented by formula (II): wherein R and X are as defined above,in the presence of a ruthenium-optically active phosphine complex as a catalyst, and then recovering the optically active carnitine ester represented by formula (I) which has been formed, wherein said ruthenium-optically active phosphine complex is selected from the group consisting of a compound represented by formula (III): RuxHyClz(R1—BINAP)2(Q)p (III) wherein R1—BINAP represents a tertiary phosphine represented by formula (IV): R1 represents a hydrogen atom, a methyl group or a t-butyl group; Q represents a tertiary amine; y is 0, x represents 2, z represents 4, and p represents 1; a compound represented by formula (VI): wherein R1—BINAP is as defined above; and R2 represents a lower alkyl group or a trifluoromethyl group; and a compound represented by formula (VII):[Ru(R1—BINAP)MClk]lXm1 (VII) wherein R1—BINAP is as defined above; M represents Zn, Al, Ti or Sn; X1 represents N(C2H5)3 or CH3CO2; in the case that X1 represents N(C2H5)3, l is 2 and m is 1, and when M represents Zn, then k is 4, when M represents Al, then k is 5, and when M represents Ti or Sn, then k is 6; and in the case that X1 represents CH3CO2, l is 1 and m is 2, and when M represents Zn, then k is 2, when M represents Al, then k is 3, and when M represents Ti or Sn, then k is 4.
- 2. A process as claimed in claim 1, wherein said ruthenium-optically active phosphine complex is used in an amount of from {fraction (1/50)} to {fraction (1/5000)} mole per mole of the compound of formula (II).
- 3. A process as claimed in claim 2, wherein said ruthenium-optically active phosphine complex is used in an amount of from {fraction (1/50)} to {fraction (1/1000)} mole per mole of the compound of formula (II).
- 4. A process as claimed in claim 1, wherein the hydrogenation is carried out at a temperature of from 15 to 100° C. and at a hydrogen pressure of from 10 to 150 kg/cm2 for a period of from about 2 to 40 hours.
- 5. A process as claimed in claim 4, wherein the hydrogenation is carried out at a temperature of from 35 to 70° C. and at a hydrogen pressure of from 25 to 50 kg/cm2 for a period of from about 5 to 30 hours.
- 6. A process as claimed in claim 1, wherein the hydrogenation is carried out in an amphiprotic solvent.
- 7. A process as claimed in claim 6, wherein the solvent is ethanol.
- 8. A process as claimed in claim 6, wherein the solvent is used in an amount of from 2 to 10 times the weight of the compound of formula (II).
- 9. A process as claimed in claim 8, wherein the solvent is used in an amount of from 3 to 5 times the weight of the compound of formula (II).
- 10. A process as claimed in claim 1, wherein said ruthenium-optically active phosphine complex is represented by formula (VI): wherein R1—BINAP is a tertiary phosphine represented by formula (IV): wherein R1 represents a hydrogen atom, a methyl group or a t-butyl group; and wherein R2 represents a lower alkyl group or a trifluoromethyl group.
- 11. A process as claimed in claim 10, wherein R2 represents a lower alkyl group.
- 12. A process as claimed in claim 10, wherein R2 represents a trifluoromethyl group.
- 13. A process as claimed in claim 1, wherein said ruthenium-optically active phosphine complex is represented by formula (VII):[Ru(R1—BINAP)MClk]lXm1 (VII) wherein R1—BINAP is a tertiary phosphine represented by formula (IV): wherein R1 represents a hydrogen atom, a methyl group or a t-butyl group; and wherein M is Zn, Al, Ti or Sn; and X1 is N(C2H5)3 or CH3CO2; andin the case that X1 is N(C2H5)3, l is 2 and m is 1; and when M is Zn, then k is 4; when M is Al, then k is 5; when M is Ti or Sn, then k is 6; and in the case that X1 is CH3CO2, l and m is 2; and when M is Zn, then k is 2, when M is Al, then k is 3; and when M is Ti or Sn, then k is 4.
- 14. A process as claimed in claim 13, wherein X1 represents N(C2H5)3.
- 15. A process as claimed in claim 13, wherein X1 represents CH3CO2.
- 16. A process as claimed in claim 13, wherein M represents Zn.
- 17. A process as claimed in claim 13, wherein M represents Al.
- 18. A process as claimed in claim 13, wherein M represents Ti or Sn.
- 19. A process as claimed in claim 1, wherein the steric configuration of the optically active carnitine ester of formula (I) is controlled so that S-compounds are obtained by using (R)-(+)-BINAP.
- 20. A process as claimed in claim 1, wherein the steric configuration of the optically active carnitine ester of formula (I) is controlled so that R-compounds are obtained by using (S)-(−)-BINAP.
- 21. A process as claimed in claim 1, wherein the ruthenium-optically active phosphine complex is Ru((−)-BINAP) [OC(═O)CH3]2.
- 22. A process as claimed in claim 1, wherein R represents a lower alkyl group having two to four carbon atoms.
- 23. A process as claimed in claim 6, wherein the solvent is isopropanol.
- 24. A process as claimed in claim 1, wherein said ruthenium-optically active phosphine complex is used in an amount of from {fraction (1/50)} to {fraction (1/5,000)} mole per mole of the compound of formula (II), the hydrogenation is carried out at a temperature of from 15 to 100° C. and at a hydrogen pressure of from 10 to 150 kg/cm2 for a period of from about 2 to 40 hours, in am amphiprotic solvent and wherein the amphiprotic solvent is used in an amount of from 2 to 10 times the weight of the compound of formula (II).
Priority Claims (1)
Number |
Date |
Country |
Kind |
63-324651 |
Dec 1988 |
JP |
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Parent Case Info
This is a Continuation of application Ser. No. 07/455,023 filed Dec. 22, 1989.
US Referenced Citations (5)
Foreign Referenced Citations (2)
Number |
Date |
Country |
0169614 |
Jan 1986 |
EP |
0339764 |
Nov 1989 |
EP |
Non-Patent Literature Citations (2)
Entry |
Kitamura, M. et al, Tetrahedron Letters, 29:13 1555-1556 (1988). |
Noyori, R. et al, Journal of American Chemical Society, vol. 109, 5856-5858 (1987). |
Continuations (1)
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Number |
Date |
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Parent |
07/455023 |
Dec 1989 |
US |
Child |
08/139861 |
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US |