To obtain the 2-nitroimidazole-based prodrugs, we planned a three-step synthetic scheme. The first step involved the synthesis of different reported 2-aminobenzamides I-II and IV-VI, which were synthesized according to previously reported procedures . The second step was the synthesis of 1-methyl-2-nitro-1H-imidazole-5-methanol (1), which was prepared according to our previously reported method . Then, the alcohol intermediate The synthesized prodrugs, in addition to the parent HDAC inhibitors, were tested for their inhibitory activity against human class I HDACs (HDAC1, 2, and 3) using a fluorogenic peptide derived from p53 (Ac-RHKK(Acetyl)-AMC) (Table ). The prodrugs were tested against HDAC1, 2, and 3 at three different concentrations (10, 1, and 0.1 µM) (Table , Supp. Information Tables ). As previously described , compounds IV-VI were designed as a novel series of class I HDAC inhibitors based on different structural modifications of the general scaffold of the reported HDAC 1-3 inhibitors tacedinaline (I) and entinostat (III). For the previously developed HDAC inhibitors we showed target engagement by measuring the hyperacetylation on H3K9 (HDAC1 substrate). For the developed inhibitors the phenyl ring in the middle of tacedinaline was replaced with the more polar pyrazine ring as in the case of compound VI, which showed improved inhibitory activity against HDAC1-3 compared to tacedinaline (Table ). On the other hand, the replacement of the phenyl ring with a pyrimidine ring, as in the case of compound V, resulted only in a slight decrease in the inhibitory activity against HDAC1 compared to compound VI.