| Number | Name | Date | Kind |
|---|---|---|---|
| 3211679 | updegraff | Oct 1965 | |
| 3717655 | Godefroi | Feb 1973 | |
| 4723984 | Holmwood et al. | Feb 1988 | |
| 4983589 | Tsang et al. | Jan 1991 | |
| 5348947 | Patel | Sep 1994 |
| Number | Date | Country |
|---|---|---|
| 1218623 | Jan 1971 | GBX |
| Entry |
|---|
| Farf an et al, J. Chem. Soc. Perkin Trans. 2, pp. 527-532 (1992). |