Table 3. Dissociation Constants (K_d) of 4, 5, 6, 7, and 8 Determined by ITC Measurements^a.

compound	Kd (nM)
4	120 ± 30
5	40 ± 19
6	66 ± 3.0
7	53 ± 16
8	42 ± 9.0
1	138 ± 13
3	78 ± 16

^aThe K_d values of 1 and 3 are indicated for comparison. Each experiment was independently conducted four to six times. All results are presented as average values with their corresponding standard deviations.