Table 1.

Chiral piperazine analogs

Compd	R1	R2	mGlu1 pIC50a (±SEM)	mGlu1 IC50 (nM)	% Glu maxa,b (±SEM)
7	H	H	6.20 ± 0.21	630	1.1 ± 0.8
14	(S)-CH3	H	5.62 ± 0.18	2420	−1.4 ± 2.5
15	(R)-CH3	H	6.79 ± 0.15	161	2.5 ± 0.5
16	H	(S)-CH3	6.01 ± 0.13	988	1.8 ± 1.0
17	H	(R)-CH3	6.78 ± 0.14	166	2.0 ± 0.4

^aCalcium mobilization mGlu₁ assay; values are average of n≥3.

^bAmplitude of response in the presence of 30 µM test compound as a percentage of maximal response (100 µM glutamate); average of n≥3.