Chao Tian

Design, synthesis, and biological evaluation of (e)-3,4-dihydroxystyryl aralkyl sulfones and sulfoxides as novel multifunctional neuroprotective agents.

Novel (E)-3,4-dihydroxystyryl aralkyl sulfones and sulfoxides were designed and synthesized as new analogues of 1, which showed interesting multifunctional neuroprotective effects, including antioxidative and antineuroinflammatory properties. Specifically, target compounds display excellent potency in scavenging reactive free radicals and demonstrate potent effects against various kinds of toxicities, including H2O2, 6-hydroxydopamine, and lipopolysaccharide in different types of neuronal cells. The antioxidative properties of the target compounds are more potent than that of 1, and the antineuroinflammatory properties are less strong than that of 1. According to the parallel artificial membrane permeation assay for the blood-brain barrier, target compounds possess greater blood-brain barrier (BBB) permeability than 1. In short, due to improvement of the antioxidative effect, stability, and BBB permeability, (E)-3,4-dihydroxystyryl aralkyl sulfones and sulfoxides can thus be considered as potential multifunctional neuroprotective agents and serve as new lead candidates in the treatment of neurodegenerative diseases.

Novel Pyridinone Derivatives As Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs) with High Potency against NNRTI- Resistant HIV‑1 Strains

Novel 6-substituted-4-cycloalkyloxy-pyridin-2(1H)-ones were synthesized as non-nucleoside reverse transcriptase inhibitors (NNRTIs), and their biological activity was evaluated. Most of the compounds, especially 26 and 22, bearing a 3-isopropyl and 3-iodine group, respectively, exhibited highly potent activity against wild-type HIV-1 strains and those resistant to reverse transcriptase inhibitors (RTIs). The diastereoisomers of 26-trans and 26-cis were synthesized separately and confirmed with HPLC and NOESY spectra. The 26-trans isomers had an activity about 400-fold more potent than that of 26-cis. The pair of 26-trans enantiomers, one of the most potent inhibitors with EC50 of 4 nM and selectivity index (SI) of 75000, was highly effective against a panel of RTIs-resistant strains with single (Y181C and K103N) or double (A17) mutations in reverse transcriptase. The results suggest that these novel pyridinone derivatives have the potential to be further developed as new antiretroviral drugs with improved antiviral efficacy and drug resistance profile.

Mechanism-based design, synthesis and biological studies of N5-substituted tetrahydrofolate analogs as inhibitors of cobalamin-dependent methionine synthase and potential anticancer agents

A number of 8-deazatetrahydrofolates bearing electrophilic groups on N(5) were designed and synthesized based on the action mechanism of methionine synthase, and their biological activities were investigated as well. Compounds (11b, 12b and 16) showed the most active against methionine synthase (IC(50): 8.11 μM, 1.73 μM, 1.43 μM). In addition, the cytotoxicity to human tumor cell lines and dihydrofolate reductase (DHFR) inhibition by target compounds were evaluated.

Synthesis and neuroprotective effect of E-3,4-dihydroxy styryl aralkyl ketones derivatives against oxidative stress and inflammation

E-3,4-Dihydroxy styryl aralkyl ketones as well as their 3,4-diacetylated derivatives as the analogues of neuroprotective agent CAPE were designed and synthesized for improving stability and lipid solubility. The neuroprotective activities of target compounds 10a-g and 11a-g were tested by three models in vitro, including 1,1-diphenyl-2-picrylhydrazyl radical scavenging capacity, neuronal protecting effect against damage induced by H2O2 in PC12 cells and nitric oxide suppression effect in BV2 microglial cells. The results demonstrated that compounds 10f and 11f exhibited the most potent neuroprotective effect against oxidative stress and inflammation, which is higher than that of the lead compound CAPE.

Design, synthesis and pharmacological evaluation of (E)-3,4-dihydroxy styryl sulfonamides derivatives as multifunctional neuroprotective agents against oxidative and inflammatory injury

A novel class of (E)-3,4-dihydroxy styryl sulfonamides and their 3,4-diacetylated derivatives as caffeic acid phenethyl ester (CAPE) analogs was designed and prepared for improving stability and solubility of the lead compound. Their neuroprotective properties were assessed by several models. The results showed that target compounds displayed positive free radical quenching abilities, superior to that of CAPE. Compounds 6j-k and 7j-k demonstrated remarkable protection effects against damage induced by hydrogen peroxide which were apparently stronger than that of CAPE. Most of target compounds could inhibit nitric oxide production. Additionally, target compounds showed high blood-brain barrier permeability.

Synthesis and Biological Evaluation of Novel 2-Arylalkylthio-5-iodine-6-substituted-benzyl-pyrimidine-4(3H)-ones as Potent HIV-1 Non-Nucleoside Reverse Transcriptase Inhibitors

A novel series of 2-arylalkylthio-5-iodine-6-substitutedbenzyl-pyrimidine-4(3H)-ones (S-DABOs) 8a–x had been synthesized via an efficient method. Their biological activity against HIV virus and RT assay were evaluated. Some compounds, especially 8h, 8l and 8n, displayed promising activity against HIV-1 RT with IC50 values in a range of 0.41 μM to 0.71 μM, which were much better than that of nevirapine. Molecular modeling studies revealed that the binding mode would be affected via forming an additional hydrogen bond by incorporating an oxygen atom on the C-2 side chain. The biological activity was in accordance with the docking results.

Synthesis and biological evaluation of pyridinone analogues as novel potent HIV-1 NNRTIs

A novel 2-pyridinone scaffold was rationally designed and synthesized based on the active anti-HIV agent 1 (LAM-trans) via an efficient method. The biological results revealed that some target compounds inhibited HIV-1 reverse transcriptase in the lower micromolar concentration range (IC50 0.089-0.68 μm). Notably, the most promising compound 25b exhibited extremely potent inhibitory activity against HIV-1 replication with an EC50 value of 0.0563 μM and the viral selectivity index amounted to 3466.8. Molecular modeling studies were performed, and some SARs were rationalized.

Synthesis, Antifolate and Anticancer Activities of N(5) -Substituted 8,10-Dideazatetrahydrofolate Analogues.

Based on our previous work, seven N5‐substituted 8,10‐dideazatetrahydrofolate analogues and one 8‐deazatetrahydrofolate analogue were designed and synthesized as human dihydrofolate reductase (hDHFR) inhibitors. All compounds were assayed versus DHFR and five different cancer cell lines. The biological assay indicated that replacing N10 with carbon would significantly increase inhibitory activities against DHFR and cytotoxicities against cancer cell lines. Compound 19a with 4‐amino and N5‐formyl showed great antitumour activities against HL‐60, Bel‐7402 and BGC823 which were much better than MTX.

Neuroprotective effects of (E)-3,4-diacetoxystyryl sulfone and sulfoxide derivatives in vitro models of Parkinson's disease

Abstract (E)-3,4-dihydroxystyryl aralkyl sulfones and sulfoxides have been reported as novel multifunctional neuroprotective agents in previous studies, which as phenolic compounds display antioxidative and antineuroinflammatory properties. To further enhance the neuroprotective effects and study structure-activity relationship of the derivatives, we synthesized their acetylated derivatives, (E)-3,4-diacetoxystyryl sulfones and sulfoxides, and examined their neuroprotective effects in vitro models of Parkinson’s disease. The results indicate that (E)-3,4-diacetoxystyryl sulfones and sulfoxides can significantly inhibit kinds of neuron cell injury induced by toxicities, including 6-OHDA, NO, and H2O2. More important, they show higher antineuroinflammatory properties and similar antioxidative properties to corresponding un-acetylated compounds. Thus, we suggest that (E)-3,4-diacetoxystyryl sulfones and sulfoxides may have potential for the treatment of neurodegenerative disorders, especially Parkinson’s disease.

Synthesis and biological evaluation of 2,6-disubstituted- 9H -purine, 2,4-disubstitued-thieno[3,2- d ]pyrimidine and -7H -pyrrolo[2,3- d ]pyrimidine analogues as novel CHK1 inhibitors

Checkpoint kinase 1 (CHK1) inhibitors can potentiate the effectiveness of deoxyribonucleic acid (DNA) damaging agents in the treatment of cancer. A novel series of 2,6-disubstituted-9H-purine (3a-p, 5a and 5b), 2,4-disubstituted-thieno[3,2-d]pyrimidine (8a-c) and 2,4-disbustituted-7H-pyrrolo[2,3-d]pyrimidine (11a-c) analogues were designed and synthesized as potent CHK1 inhibitors. Compounds (3a, 3d, 3f and 3j-l) with 9H-purine core displayed more potent inhibition against CHK1. The most potent compound (3l) also exhibited low anti-proliferative effects towards HT29 and Hek293 cell lines. In addition, 3l showed strong potentiating effect (7-fold) on the anti-proliferative activity of gemcitabine towards HT29 cells. The results of cell cycle assay indicated that 3l could strikingly affect the cell cycle distribution of the gemcitabine-treated HT29 cells and induce a significant S phase accumulation. The kinase selectivity profile of 3l displayed acceptable selectivity against other kinases. These results rendered 3l a potent lead compound of CHK1 inhibitor for further investigation.