| Number | Date | Country | Kind |
|---|---|---|---|
| 1-121366 | May 1989 | JPX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4876263 | Shiokawa et al. | Oct 1989 |
| Number | Date | Country |
|---|---|---|
| 366085 | May 1990 | EPX |
| 64-3184 | Jan 1989 | JPX |
| Entry |
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| Chem. Ber., vol. 119, pp. 2208-2219 (1968). |
| J. Chem. Soc. Perkin Trans. I, 1979, pp. 2361-2363. |
| Journal of Heterocyclic Chem., vol. 17, p. 1413 (1980). |
| Heterocycles 15, p. 437 (1980). |