Claims
- 1. Process for preparing a compound of general formula I
- 2. Process according to claim 1, characterized in that the compound of general formula I is obtained in the form of a mixture of its 2 isomers 4″R and 4″S.
- 3. Process according to claim 1, characterized in that the 4″R isomer is obtained as the major product.
- 4. Process according to claim 1, characterized in that the nitrogenous reagent is chosen from ammonia, ammonium salts, for instance ammonium acetate or ammonium hydrochloride, primary amines NH2RA, secondary amines NH(RA)2 with the radicals RA, which may be identical or different, representing a C1 to C10 alkyl or C6 to C12 aryl group or a silyl group of the type SiRBRCRD in which the groups RB, RC and RD, which may be identical or different, can be an alkyl or aryl group.
- 5. Process according to claim 4, characterized in that the nitrogenous reagent is chosen from benzylamine, hexamethyldisilazane and ammonia.
- 6. Process according to claim 1, characterized in that the nitrogenous reagent is introduced in a proportion of from 1 to 30 equivalents relative to the compound of general formula II and preferably in a proportion of from 1 to 10 equivalents.
- 7. Process according to claim 1, characterized in that the Lewis acid is aprotic.
- 8. Process according to claim 1, characterized in that the Lewis acid is introduced in a proportion of from 1 to 30 equivalents relative to the compound of general formula II.
- 9. Process according to claim 1, characterized in that the Lewis acid is chosen from organometallic complexes of the elements from column IVB, IIIA or IIB of the Periodic Table of the Elements.
- 10. Process according to claim 9, characterized in that the said complex is chosen from titanium(IV) isopropoxide, aluminium(III) isopropoxide, titanium(IV) isopropoxide bis(acetylacetonate) and zinc(II) trifluoroacetate.
- 11. Process according to claim 1, characterized in that the reducing agent is a metal hydride.
- 12. Process according to claim 11, characterized in that it is a boron or aluminium hydride.
- 13. Process according to claim 11, characterized in that it is sodium, lithium or zinc borohydride.
- 14. Process according to claim 1, characterized in that it is used in the presence of an organic solvent chosen from aromatic hydrocarbons, in particular toluene, halogenated solvents such as dichloromethane, alcohols such as methanol, nitrites such as acetonitrile, ethers such as THF or sulphoxides such as DMSO.
- 15. Process according to claim 1, characterized in that the Lewis acid is titanium isopropoxide or aluminium isopropoxide, the nitrogenous reagent is ammonia, hexamethyldisilazane or benzylamine, and the solvent is dichloromethane, tetrahydrofuran or toluene.
- 16. Process according to claim 15, characterized in that the reducing agent is sodium borohydride or lithium borohydride.
- 17. Process according to claim 1, characterized in that the compound of formula II dissolved in an organic solvent is added to the mixture of the Lewis acid and the nitrogenous reagent.
- 18. Process according to claim 1, characterized in that the compound of formula II and the Lewis acid are mixed together in an organic solvent and the nitrogenous reagent is added slowly to this mixture.
- 19. Process according to claim 1, characterized in that the compound of formula II is mixed with the nitrogenous reagent in an organic solvent and the Lewis acid is then added.
Priority Claims (1)
Number |
Date |
Country |
Kind |
00 06942 |
May 2000 |
FR |
|
Parent Case Info
[0001] This application claims priority from U.S. application Ser. No. 60/219,513, filed Jul. 20, 2000 and French application Ser. No. 00 06942, filed May 30, 2000. Each of these applications and each document cited or referenced in each of these applications (“application cited documents”), and each document cited or referenced in application cited documents, are hereby incorporated herein by reference.
Provisional Applications (1)
|
Number |
Date |
Country |
|
60219513 |
Jul 2000 |
US |