Inhibitory effects of compounds 3a–3o against CDK2/cyclin A and CDK9/cyclin T1.

Compd.	R3	R4	R5	IC50a (μM)
				CDK2/cyclin A	CDK9/cyclin T1
2e	H	H		0.24 ± 0.04	0.095 ± 0.004
3a	H	H		1.10 ± 0.15	0.48 ± 0.22
3b	H	H		0.38 ± 0.06	0.08 ± 0.001
3c	H	H		0.30 ± 0.07	0.065 ± 0.023
3d	H	H		0.13 ± 0.02	0.66 ± 0.02
3e	H	H		0.75 ± 0.14	0.23 ± 0.01
3f	F	H		NDb	ND
3g	H	F		0.083 ± 0.035	0.10 ± 0.01
3h	OCH3	H		ND	ND
3i	H	OCH3		0.57 ± 0.08	0.19 ± 0.02
3j	H	CH3		2.90 ± 0.06	0.16 ± 0.02
3k	H		H	0.44 ± 0.04	0.083 ± 0.002
3l		H	H	ND	ND
3m	H	H		0.47 ± 0.04	0.290 ± 0.002
3n	H	H		0.95 ± 0.27	1.6 ± 0.1
3o	H	CH3		5.60 ± 0.03	0.74 ± 0.04

^aThe IC₅₀ value was interpolated from dose–response data with six different concentrations. Each test was performed in duplicate. Data represent the average of duplicate measurements.

^bNot determined due to the lack of significant inhibition at the concentration of 10 μM.