Table 2. SAR of S-Linked Series^a.

	X	IC50	L929		X	IC50	L929
thioether
5	2-Cl	0.58	>10	21	2-CO2Me	0.14	>10
6	3-Cl	0.12	1.11	22	3-OMe	0.12	2.64
7	4-Cl	0.15	2.02	23	4-NHCOMe	0.04	>10
8	3,4-Cl2	0.49	0.56	24	4-NH2	0.03	>10
20	4-NO2	0.32	>10
sulfoxide
10	2-Cl	0.18	>10	12	4-Cl	0.12	8.87
11	3-Cl	0.15	>10	13	3,4-Cl2	0.30	2.67
sulfone
15	2-Cl	0.10	>10	17	4-Cl	0.16	>10
16	3-Cl	0.22	>10	18	3,4-Cl2	0.52	>10

^aIC₅₀: growth inhibition of T. b. brucei 427 strain (μg/mL). L929: IC₅₀ against L929 cells (μg/mL). References: suramin and pentamidine.