Claims
- 1. A process to prepare the E isomer of a 3-substituted (6R,7R)-7-phenyl-acetamido-ceph-3-em-4-carboxylic acid from a mixture of the E and Z-isomer of either the corresponding tert-butyl or the corresponding 4-methoxybenzyl ester of a 3-substituted (6R,7R)-7-phenylacetamido-ceph-3-em-4-carboxylate, characterized by the application of a compound selected from the group titanium tetrachloride, tin tetrachloride and tellurium tetrachloride.
- 2. A process according to claim 1, characterized by the preparation of the E-isomer of (6R,7R)-3-(2,4-dinitrostyryl)-7-phenylacetamido-ceph-3-em-4-carboxylic acid from a mixture of the E and Z-isomer of the tert-butyl ester of (6R,7R)-3-(2,4-dinitrostyryl)-7-phenylacetamido-ceph-3-em-4-carboxylic acid.
Priority Claims (1)
Number |
Date |
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95202992 |
Nov 1995 |
EPX |
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PRIOR APPLICATION
This application is a continuation of U.S. patent application Ser. No. 09/051,189 filed Apr. 1, 1998, now U.S. Pat. No. 5,922,861 which is a 371 filing of PCT Application PCT/EP96/04880 filed Nov. 6, 1996.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4985554 |
Verweig et al. |
Jan 1991 |
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5922861 |
De Vroom et al. |
Jul 1999 |
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Continuations (1)
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Parent |
051189 |
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