Table 1.

Initial screening data of analogs of lapatinib 1.

Compd	GSK Number	R1	R2	R3	Tbb EC50 (μM)a,b
2	GW58337A		Cl	H	0.41
3	GW601906A		Cl	F	0.43
4	GW633460A		Cl	F	0.48
5	GW616030X		Cl	F	0.52
6	GW615311X		Cl	F	0.55
7	GW580496A		Br	H	0.56
8	GW576924A		F	F	0.60
9	GW616907X		Cl	F	1.51
1	lapatinib		Cl	F	1.54
	melarsoprol49				0.0063
	eflornithine50				16.4
	pentamidine49				0.0035
	SCYX-715851				0.794

^aAll EC₅₀ values are ± 7%.

^bConcentration giving 50% inhibition of growth of T brucei brucei Lister 427 cells