| Number | Name | Date | Kind | 
|---|---|---|---|
| 2658889 | Goldberg et al. | Nov 1953 | |
| 3157569 | Addor et al. | Nov 1964 | |
| 3839564 | Wright et al. | Oct 1974 | |
| 4830957 | Sato et al. | May 1989 | |
| 4837142 | Sato et al. | Jun 1989 | 
| Number | Date | Country | 
|---|---|---|
| 765569 | Nov 1979 | FRX | 
| 1355304 | Jun 1974 | GBX | 
| Entry | 
|---|
| Hassaneen et al., Heterocycles, 36(8):1775-1781, 1993. |