Table 2.

SAR results for select analogues from libraries 17–21 chosen based on an initial single-point potentiation screen at rat M₄.^[a]

Compd	R1	R2	EC50[b] [μM]	Fold-shift[c]
17 a			2.58	7 x
17 o			2.75	14 x
18 a			7.42	40 x
18 b			6.25	67 x
18 c			5.81	51 x
18 g			7.15	36 x
18 h			8.73	62 x
19 m			5.40	28 x
19 n			> 10	41 x
21 n			2.44	44 x
21 o			3.78	64 x

^[a]These data represent the mean values from at least three experiments with similar results.

^[b]Concentration of compound eliciting an effect 50 % of its own maximal potentiation of an ACh EC₂₀.

^[c]Leftward shift of an ACh CRC in the presence of 30 μM compound relative to ACh CRC control.