| Number | Name | Date | Kind |
|---|---|---|---|
| 4370257 | Imai et al. | Jan 1987 | |
| 4609754 | Hall et al. | Sep 1986 | |
| 4792640 | Mehta | Dec 1989 | |
| 4820879 | Mehta | Apr 1989 | |
| 4952737 | Inkrott | Aug 1990 |
| Number | Date | Country |
|---|---|---|
| 36510 | Feb 1985 | JPX |
| Entry |
|---|
| Cason "Essential Principles of Organic Chemistry" (1956) pp. 25-30. |