Table 1.

Experimental binding affinities (IC₅₀) of the isatin sulfonamide analogues to caspase-3 used in this study. All values represent the average (± standard error) of multiple determinations as reported in literature.¹⁰, ¹¹

Ligand	R1	R2	R3	IC50 (nM)
Region I: Pyrrolidine analogues
1		—CH3	=O	119.2 ± 17.0
2		—H	=O	240.0 ± 10.0
3			=O	12.2 ± 0.3
4			=O	14.5 ± 1.6
5			=O	12.1 ± 2.1
6			=O	12.4 ± 2.1
7			=O	12.0 ± 1.5
8			=O	13.5 ± 2.4
9			=O	9.85 ± 0.9
10			=O	10.3 ± 1.5
11			=O	21.3 ± 3.2
12			=O	9.1 ± 1.8
13			=O	9.7 ± 1.3
14		—H	=O	58.3 ± 7.6
15		—CH3	=O	23.3 ± 3.1
16			=O	5.2 ± 1.6
17			=O	3.9 ± 0.9
18			=O	4.4 ± 1.4
19			=O	8.4 ± 2.0
20			=O	3.9 ± 0.6
21			=O	3.6 ± 0.5
22		—H	=O	20.4 ± 1.7
23		—H		272 ± 24.7
24		—CH3		119.3 ± 4.0
25				27.8 ± 2.5
26				31.8 ± 6.2
27				20.1 ± 1.3
28				7.6 ± 1.1
29				7.8 ± 1.9
30				5.1 ± 0.7
31				7.8 ± 1.5
Region I: Azetidine analogues
32		—H	=O	286.7 ± 24.7
33		—CH3	=O	91.7 ± 7.6
34			=O	9.7 ± 1.6
35			=O	8.4 ± 1.2
36			=O	11.3 ± 1.2
37			=O	8.8 ± 1.4
38			=O	9.4 ± 0.3
39			=O	10.9 ± 1.4
40			=O	29.2 ± 5.2
41			=O	5.8 ± 1.0
Region I: Miscellaneous rings
42			=O	1430 ± 40
43			=O	1028 ± 259
44				583 ± 68
45				1405 ± 219
46				529 ± 69.3
47				4700 ± 700
48				4633 ± 1000
49				1550 ± 70.0
50				1454 ± 170
51				1672 ± 348
52				1993 ± 86
53			=O	114.2 ± 30.4
54				323 ± 15.6
55				718 ± 216
56				365 ± 48.8
57				671 ± 107
58				673 ± 31.8
59				724 ± 151