•Twenty-one novel 2,4,5-trisubstituted thiazoles were designed and synthesized.•Reasonable design and combination of optimal substituents increased the activity.•SAR exploration focused on positions 4 and 5 of the thiazole ring.•Some compounds showed inhibition against both WT and some mutant viruses.In our previous work, novel 2,4,5-trisubstituted thiazole derivatives (TSTs) were synthesized, and their activities were evaluated against HIV-1 reverse transcriptase. Some interesting results were obtained, which led us to a new discovery regarding these TSTs. In the present study, 21 new 2,4,5-trisubstituted thiazole derivatives were rationally designed and synthesized as HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) in accordance with our previous study. Among the synthesized target compounds, compounds 14, 16, 17, and 19 showed more potent inhibitory activities against HIV-1 with an IC50 value of 0.010 μM. Compounds 4, 9, 10, 11, 13 and 16 were further tested on nine NNRTI-resistant HIV-1 strains, and all of these compounds exhibited inhibitory effects. A molecular docking study was conducted, and the results showed a consistent and stable binding mode for the typical compounds. These results have provided deeper insights and SAR of these types of NNRTIs.

•2,4,5-Trisubstituted thiazole, a novel scaffold as NNRTIs.•30 compounds inhibited HIV-1 replication with IC50 0.046–9.59 μM.•Compounds 8, 9, 21, 23, 24 showed inhibition against WT and seven common mutants.•We studied the SAR and the possible binding mode of this type NNRTIs.•The 3D-QSAR results gave the further direction to the research.Novel 2,4,5-trisubstituted thiazole derivatives (TSTs) were designed and synthesized as HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs). Among the thirty-eight synthesized target compounds, thirty TSTs showed potent inhibition against HIV-1 replication in wild type HIV-1 at submicromolar concentrations (from 0.046 to 9.59 μM). Compounds 21, 23 and 24 were also tested on seven NNRTI-resistant HIV-1 strains, and all exhibited inhibitory effects with fold changes in IC50 ranging from 2.6 to 111, which were better than those of nevirapine (15.6-fold–371-fold). Docking simulations of compound 24 revealed a reasonable mechanism for the binding mode, and three-dimensional quantitative structure activity relationship (3-DQSAR) studies on this novel series of TST further elucidated the structure–activity relationship (SAR). The results suggested the great potential of TSTs as a novel class of NNRTIs with antiviral efficacy and a good resistance profile.

A series of 2-(6-methylpyridin-2-yl)-1H-imidazoles were synthesized and evaluated for ALK5 inhibitory activity in cell-based luciferase reporter assays. The compound 4-(((1-(benzo[d][1,3]dioxol-5-yl)-2-(6-methylpyridin-2-yl)-1H-imidazol-4-yl)methyl)amino)benzenesulfonamide (27a) exhibited slightly higher inhibition (IC50 = 0.24 μM) than SB431542 (IC50 = 0.35 μM), a well known potent ALK5 inhibitor. The binding mode of 27a generated by flexible docking study shows that it fits well into the site cavity of ALK5 by forming several tight interactions.The synthesis of 1,2,4-trisubstituted imidazoles and evaluation for their ALK5 inhibitory activity is reported. A comparison of molecular docking between 27a and SB431542 is reported.