Table 3.

IC₅₀ values of the AChE and BChE inhibitory effects of 2(a–o).

Compounds	Substituents				IC50 (µM) AChE	IC50 (µM) BChE
2a	R1 = adamantan-1-yl	R2 = H	R3 = H	R4 = H	>2000	>2000
2b	R1 = adamantan-1-yl	R2 = CH3	R3 = H	R4 = H	657 ± 60	706 ± 37
2c	R1 = adamantan-1-yl	R2 = H	R3 = CH3	R4 = H	270 ± 21	>2000
2d	R1 = adamantan-1-yl	R2 = H	R3 = H	R4 = CH3	>2000	>2000
2e	R1 = adamantan-1-yl	R2 = H	R3 = Cl	R4 = H	>2000	>2000
2f	R1 = 1,1′-biphenyl	R2 = H	R3 = H	R4 = H	208 ± 17	>2000
2g	R1 = 1,1′-biphenyl	R2 = CH3	R3 = H	R4 = H	288 ± 48	315 ± 6
2h	R1  =1,1′-biphenyl	R2  =H	R3  =H	R4  =CH3	79 ± 10	496 ± 27
2i	R1 = 1,1′-biphenyl	R2 = Cl	R3 = H	R4 = H	253 ± 25	>2000
2j	R1 = 3,4-dichlorophenyl	R2 = H	R3 = H	R4 = H	>2000	65 ± 13
2k	R1 = 3,4-dichlorophenyl	R2 = CH3	R3 = H	R4 = H	>2000	191 ± 29
2l	R1 = 4-methoxyphenyl	R2 = H	R3 = H	R4 = H	>2000	>2000
2m	R1 = 4-methoxyphenyl	R2 = CH3	R3 = H	R4 = H	>2000	>2000
2n	R1 = 4-chlorophenyl	R2 = CH3	R3 = H	R4 = H	>2000	722 ± 48
2o	R1 = 4-bromophenyl	R2 = CH3	R3 = H	R4 = H	>2000	>2000
Tacrine					0.24 ± 0.04	0.03 ± 0.01