Table 4.

In vitro antiproliferative activity for selected HDAC inhibitors.

Compd	IC50 (μM)a
	K562	Molt-4	HEL	PC-3	SK-N-BE(2)
9a	NDb	ND	2.27	ND	ND
9d	1.75	1.24	0.69	1.27	0.93
9h	2.83	2.46	1.15	11.35	1.92
9m	1.54	0.75	0.53	4.82	0.96
9n	1.48	0.70	0.58	3.23	1.01
23a	5.28	5.13	2.75	10.19	8.98
MS-275	1.32	0.65	0.48	4.89	0.33

^aAssays were performed in replicate (n ≥ 2), the SD values are <20% of the mean.

^bNot determined.