Table 3.

Antinociceptive activities of N-methylmorphinan-6-ones 5 and 6 and their 6-CN substituted analogues 5a–9a.

	ED50 (mg/kg, s.c.) a
	Hot-Plate Test	Tail-Flick Test	PPQ Abdominal Stretching Test
5	1.37	0.94	0.38
5a	0.50	1.88	0.18
6	1.02	0.80	0.22
6a	0.25	0.21	0.11
7a	0.15	0.12	0.026
8a	0.080	0.040	0.0023
9a	0.089	0.12	0.003

^a Determined in mice after s.c. administration. Data from [81,84]. For compound structures, refer to Scheme 3, Scheme 4 and Scheme 5.