| Number | Date | Country | Kind |
|---|---|---|---|
| 3986/85 | Sep 1985 | CHX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3651216 | Ringel et al. | Mar 1972 |
| Entry |
|---|
| Edwards et al., Tetrahedron Letters, vol. 7, No. 40, pp. 4867-4870 (1966). |
| Jansen et al., Tetrahedron Letters, vol. 26, No. 49, pp. 6031-6034 (1985). |