Table 4.

Antinociceptive Activity of Compounds 7a–r in Mouse WWTW Assay^a

	C-8 substitution	antinociceptive activity at 10 mg/kg	duration of action		C-8 substitution	antinociceptive activity at 10 mg/kg	duration of action
7a	benzyl	no activity		7j	methylmorpholine	no activity
7b	methyl	fully efficacious	1.5 h	7k	methylpiperazine	did not test
7c	ethyl	fully efficacious	1.0 h	7l	phenethyl	no activity
7d	n-propyl	no activity		7m	ethyl amide	no activity
7e	n-butyl	fully efficacious	2.5 h	7n	ethyl ester	fully efficacious	2.5 h
7f	t-butyl	partially active		7o	phenyl amide	did not test
7g	fluoro	no activity		7p	benzyl amide	no activity
7h	trifluoromethyl	no activity		7q	bromo	no activity
7i	methylpiperidine	no activity		7r	carboxylic acid	no activity

^aResults from the mouse WWTW assay after ip administration of compound 7a–r at 10 mg/kg. Antinociceptive activities defined as fully efficacious for 20 s latency to tail withdrawal, partially active for 10 s above baseline, or no activity for no significant difference from baseline. Duration of action is defined here as the time it takes to return to baseline after a 10 mg/kg bolus injection of test compound.