Claims
- 1. A process for selectively isolating, in greater than about 95.0% purity, 2-deoxy-2,2-difluoro-D-erythro-pentofuranos-1-ulose-3,5-dibenzoate, which has the formula ##STR23## from an enantiomeric mixture of erythro and threo lactones of the formula ##STR24## comprising dissolving the enantiomeric mixture in methylene chloride, cooling the solution to a temperature in the range of about -5.degree. C. to about 10.degree. C., and collecting the precipitated erythro enantiomer.
- 2. A process of claim 1 comprising the additional step of adding hexane to the solution of the enantiomeric mixture dissolved in methylene chloride to provide a hexane/methylene chloride solvent mixture.
- 3. The process of claim 2 wherein the solvent mixture comprises 3 parts by volume of hexane to 2 parts by volume of methylene chloride.
- 4. A process of claim 1 comprising the additional step of adding isopropanol to the solution of the enantiomeric mixture dissolved in methylene chloride to provide an isopropanol/methylene chloride solvent mixture.
Parent Case Info
This application is a division of co-pending application 07/236,058, filed 08/24/88, now abandoned, which is a continuation-in-part of co-pending application 07/090,725, filed Aug. 28,1987, now abandoned.
US Referenced Citations (5)
Foreign Referenced Citations (3)
Number |
Date |
Country |
184365 |
Jun 1986 |
EPX |
211354 |
Feb 1987 |
EPX |
1055915 |
Jul 1951 |
FRX |
Non-Patent Literature Citations (2)
Entry |
Dowex::ION Exchange, The Dow Chemical Company, Midland, Mich., p. 71, 1959. |
Encyclopedia of Polymer Science and Engineering, Second Edition, H. F. Mark et al., eds., John Wiley and Sons, New York, 1987, vol. 8, p. 346. |
Divisions (1)
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Number |
Date |
Country |
Parent |
236058 |
Aug 1988 |
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Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
90725 |
Aug 1987 |
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