| Number | Date | Country | Kind |
|---|---|---|---|
| 4004321 | Feb 1990 | DEX | |
| 4032090 | Oct 1990 | DEX |
| Number | Date | Country |
|---|---|---|
| 0262399 | Apr 1988 | EPX |
| 0355599 | Aug 1989 | EPX |
| Entry |
|---|
| Liebigs Annalen der Chemie, No. 5, 1985, pp. 1095-1098, Wienheim, DE; R. Schmierer et al.: "Cyclisierung von N-Acylalanin- und N-Acylglycinestern". |