Table 2. SAR Study for Analogues with Substitution on the Piperazine Core.

					P. falciparum strain EC50
compd	R1	R2	R3	mouse microsome hepatic extraction ratio	3D7 (nM)	W2 (nM)
31	H	H	4-MePh	0.80	161 ± 13	178 ± 12
32	H	=O	4-MePh	0.70	1079 ± 285	1168 ± 188
33	Me	=O	4-MePh	0.72	138 ± 10	136 ± 20
34	Me	=O	3Cl,4F-Ph	0.61	36 ± 2	65 ± 3
35	Me	H	4-MePh	0.77	13 ± 2	13 ± 1
36	Me	H	4-FPh	0.80	5 ± 1	5 ± 1