Issued Patents 2003
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6538135 | Method for producing 4-amino-5-chloro-1-phenyl pyridazinone-(6) | Klaus Herbig, Erich Fretschner, Helmut Fröhlich | 2003-03-25 |
| 6515139 | Method for producing N-substituted 2-pyrazoline-5-one | Erich Fretschner, Knut Koob | 2003-02-04 |