Table 2. Activity of novel indole compounds against DYRK1A and related kinases relative to ID-8.

Compound	R1	R2	R3	IC50 (μM)
				DYRK1A	DYRK1B	DYRK2	CLK1	CLK4	GSK3α	GSK3β	LRRK2	PIM1	PIM3
ID-8	6-OH	NO2	p-OCH3	0.104	0.040	NC	1.37	1.05	0.428	0.153	0.100	0.376	0.176
34	6-OCOCH3	NHCOCH3	p-OCH3	NC	NC	NC	NC	NC	NC	NC	NC	NC	NC
28	6-OCH3	NO2	p-OCH3	0.346	0.695	NC	NC	2.23	2.36	3.44	0.854	0.176	0.259
29	6-OCH2C6H5	NO2	p-OCH3	6.52	3.57	NC	NC	NC	18.0	14.3	8.16	18.5	8.28
30	6-OCOCH3	NO2	p-OCH3	0.680	0.299	NC	NC	11.95	22.15	1.71	0.891	4.15	1.21
45	6-OH	NO2	p-OH	0.122	0.060	2.30	0.364	0.163	0.375	0.233	0.046	0.243	0.180
48	6-OH	NO2	m-OCH3	0.594	0.257	NC	13.0	4.77	2.32	0.692	2.17	0.654	0.593
49	6-OH	NO2	o-OCH3	0.829	0.341	41.9	10.7	8.59	6.12	3.82	1.98	1.44	0.892
51	5-NO2	NO2	p-OCH3	NC	NC	NC	NC	NC	NC	NC	NC	7.62	4.57
38	H	NO2	p-OCH3	NC	NC	NC	NC	NC	NC	NC	NC	NC	20.74