Acetyl cholinesterase inhibition of phenoxy pendant isatins PI1–12^a.

Compounds	R1	R2	IC50 (μg ml−1) ± SEM
PI1	H	H	0.52 ± 0.073
PI2	Cl	H	0.72 ± 0.012
PI3	Br	H	ND
PI4	F	H	0.68 ± 0.011
PI5	H	Cl	ND
PI6	Cl	Cl	0.91 ± 0.015
PI7	Br	Cl	ND
PI8	F	Cl	ND
PI9	H	Br	0.91 ± 0.083
PI10	Cl	Br	0.98 ± 0.055
PI11	Br	Br	1.14 ± 0.013
PI12	F	Br	1.31 ± 0.083
Donepezil	—	—	0.73 ± 0.015

^aND = not determined, SEM = standard error of mean.