Table 1. Apparent IC₅₀ Values of Substituted 2-(Isoxazol-3-yl)-2-oxo-N′-phenyl-acetohydrazonoyl Cyanide Scaffolds with Modifications on the Phenyl Ring for Competing with 8-NBD-cAMP in Binding to EPAC2.

Compd	R1	IC50 (μM)a	relative affinity (RA)b
cAMP		32.0 ± 5.9	1.0
1	3-Cl	8.9 ± 1.2	3.6
8	H	59.8 ± 9.4	0.5
9	2-Cl	28.3 ± 4.0	1.1
10	4-Cl	26.5 ± 4.1	1.2
11	3-Br	14.0 ± 2.4	2.3
12	3-F	22.4 ± 2.8	1.4
13	3-CF3	11.9 ± 1.7	2.7
14	3-NO2	31.3 ± 5.5	1.0
15	3-COOEt	71.4 ± 23.8	0.4
16	3-CN	67.8 ± 23.5	0.5
17	3-COCH3	NEc
18	3-OMe	NE
19	3-CH2OH	NE
20	3-Me	25.1 ± 4.8	1.3
21	2,5-di-Cl	7.3 ± 1.2	4.4
22	3,5-di-Cl	1.9 ± 0.339	16.8
23	3,4-di-Cl	3.0 ± 0.6	10.7
24	2,3-di-Cl	35.6 ± 7.9	0.9
25	3,5-di-CF3	6.4 ± 0.9	5.0
26	3-F, 5-CF3	5.8 ± 0.9	5.5
27	3,5-di-F	5.3 ± 0.8	6.0
28	3-Cl, 5-CF3	1.6 ± 0.3	20.0
29	3-F, 5-Cl	2.5 ± 0.4	12.8
30	3-F, 4-Cl	4.3 ± 0.5	7.4
31	3-Cl, 4-F	2.7 ± 0.3	11.9
32	3-CF3, 4-Cl	2.9 ± 0.5	11.0
33	3,4-di-F	6.6 ± 0.8	4.8
34	3-Cl, 4-CF3	3.6 ± 0.6	8.9
35	3,4,5-tri-Cl	0.9 ± 0.2	35.6
36	3,4,5-tri-F	1.1 ± 0.2	29.1
37	2,4,6-tri-Cl	19.0 ± 1.7	1.7

^aThe values are the mean ± SE of at least three independent experiments.

^bRA = IC_50,cAMP/IC_50,compound.

^cNE: no effect, indicating that a specific IC₅₀ cannot be calculated from the data points collected.