Synthesis and biological evaluation of carbohydrate appended hydrazinocyclopentenes with potent glycation and α-glucosidase inhibition activities

Synthesis and biological evaluation of novel alkylidenecyclopentene glycohybrids via palladium and click chemistry are described. Out of the six molecules synthesized, four molecules were screened against α-glucosidase, α-amylase, and glycation reactions. The results showed that the compound 7f with a galactose appendage is a good α-glucosidase inhibitor and a potent anti-glycation agent under in vitro conditions with an IC₅₀ value of 0.075 μM and 0.022 μM, respectively. The toxicity of the compounds against normal cell lines was checked by MTT assay.     

Solvothermal Synthesis of Multiple Dihydropyrimidinones at a Time as Inhibitors of Eg5

Solvothermal synthesis of multiple dihydropyrimidinones at a time has been developed in inexpensive and green bio-based solvent lactic acid without any additional catalysts or additives. By this method, thirty new dihydropyrimidinone derivatives were synthesized in two batches and characterized. All of the compounds were screened by Eg5 motor protein ATPase assay, and the positive compounds were tested against the Caco-2 cell line, HeLa cell line, L929 cell line and T24 cell line in vitro. Among them, compound C9 exhibited the best inhibitory activity against motor protein ATPase with an IC₅₀ value of 30.25 μM and significant cytotoxic activity in the micromolar range against the cells above. The Lineweaver–Burk plot revealed that compound C9 was a mixed-type Eg5 inhibitor. A molecular modeling study using the Discovery Studio program was performed, where compound C9 exhibited good binding interaction with Eg5 motor protein ATPase, and this was consistent with the attained experimental results.     

Total synthesis of dehydroaltenusin

The first total synthesis of dehydroaltenusin, a natural enzyme inhibitor, is described. The key step involves Suzuki-coupling reaction of an aryl triflate prepared from 2,4,6-trihydroxybenzoic acid with a catechol-derived boronic acid or boronic ester. The synthetic product was evaluated as a potent inhibitor against eukaryotic DNA polymerase α and other DNA polymerases.     

Design,Synthesis, and Antitumor Activity of Olmutinib Derivatives Containing Acrylamide Moiety

Two series of olmutinib derivatives containing an acrylamide moiety were designed and synthesized, and their IC₅₀ values against cancer cell lines (A549, H1975, NCI-H460, LO2, and MCF-7) were evaluated. Most of the compounds exhibited moderate cytotoxic activity against the five cancer cell lines. The most promising compound, H10, showed not only excellent activity against EGFR kinase but also positive biological activity against PI3K kinase. The structure–activity relationship (SAR) suggested that the introduction of dimethylamine scaffolds with smaller spatial structures was more favorable for antitumor activity. Additionally, the substitution of different acrylamide side chains had different effects on the activity of compounds. Generally, compounds H7 and H10 were confirmed as promising antitumor agents.     

Practical synthesis of a peptidomimetic thrombin inhibitor

Compound 1 is a low molecular weight thrombin inhibitor developed for treatment of deep vein thrombosis and cardiovascular diseases. We herein report our efforts to develop a robust, efficient and reproducible process suitable for large-scale synthesis of compound 1.     

Discovery of Novel Dual Extracellular Regulated Protein Kinases (ERK) and Phosphoinositide 3-Kinase (PI3K) Inhibitors as a Promising Strategy for Cancer Therapy

Concomitant inhibition of MAPK and PI3K signaling pathways has been recognized as a promising strategy for cancer therapy, which effectively overcomes the drug resistance of MAPK signaling pathway-related inhibitors. Herein, we report the scaffold-hopping generation of a series of 1H-pyrazolo[3,4-d]pyrimidine dual ERK/PI3K inhibitors. Compound 32d was the most promising candidate, with potent inhibitory activities against both ERK2 and PI3Kα which displays superior anti-proliferative profiles against HCT116 and HEC1B cancer cells. Meanwhile, compound 32d possessed acceptable pharmacokinetic profiles and showed more efficacious anti-tumor activity than GDDC-0980 and the corresponding drug combination (BVD-523 + GDDC-0980) in HCT-116 xenograft model, with a tumor growth inhibitory rate of 51% without causing observable toxic effects. All the results indicated that 32d was a highly effective anticancer compound and provided a promising basis for further optimization towards dual ERK/PI3K inhibitors.     

Two new proanthocyanidin trimers isolated from Cistus incanus L. demonstrate potent anti-inflammatory activity and selectivity to cyclooxygenase isoenzymes inhibition

Two new proanthocyanidin trimers have been isolated from Cistus incanus herb; gallocatechin-(4α→6)-gallocatechin-(4α→8)-gallocatechin (compound 1) and epigallocatechin-3-O-gallate-(4ß→8)-epigallocatechin-3-O-gallate-(4ß→8)-gallocatechin (compound 2). The structures were determined on the basis of 1D- and 2D-NMR (HSQC, HMBC) of their peracetylated derivatives, MALDI-TOF-MS and by acid-catalysed degradation with phloroglucinol. A more abundant proanthocyanidin oligomer was also isolated, purified and its chemical constitution studied by ¹³C-NMR and phloroglucinol degradation. The mean molecular weight of the polymer was estimated to be about 7 to 8 flavan-3-ol-units with a ratio of procyanidin?:?prodelphinidin units at 1:5, some of which are derivatised by gallic acid. Water extract and higher oligomeric proanthocyanidin fractions of C. incanus significantly inhibited TPA-induced oedema when applied topically at doses of 0.5 and 1 mg/ear in mice. Furthermore, the extracts and the pure compounds inhibited COX-1 and COX-2 activities. In addition, compound 2 exhibited an IC₅₀ of 4.5 μM against COX-2 indicating its high selectivity towards COX-2.     

Trienic α-pyrone and ochratoxin derivatives from a sponge-derived fungus Aspergillus ochraceopetaliformis

A new trienic α-pyrone derivative asteltoxin G (1) bearing a tetrahydrofuran ring and a new ochratoxin derivative named ochratoxin A₁ (5), along with seven known compounds, were isolated from a sponge-derived fungus Aspergillus ochraceopetaliformis. The compounds (1–9) were evaluated on the basis of spectroscopic analyses and comparison with those of the reported data. The new compound ochratoxin A₁ (5) exhibited anti-inflammatory activity against IL-6 and TNF-α expression of the LPS-induced THP-1 cells with inhibitory rates of 74.4 and 67.7% at concentration of 10 μM, respectively.     

Synthesis, α-glucosidase inhibition and molecular docking studies of natural product 2-(2-phenyethyl)chromone analogues

A series of natural product (2-phenyethyl)chromone analogues (3–34) were designed, synthesized, and screened for their α-glucosidase inhibitory activity. The results indicated that some of the synthesized derivatives displayed inhibitory activities against α-glucosidase with IC₅₀ values ranging from 11.72 ± 0.08 to 85.58 ± 2.30 μM when compared to the standard drug acarbose (IC₅₀ = 832.22 ± 2.00 μM). Among them, compound 4 with a hydroxyl group at the 7-position of chromone and a chloro group at the 4-position of the benzene ring, displayed the most significant inhibitory activity with the IC₅₀ value of 11.72 ± 0.08 μM. The inhibitory mechanism of compound 4 against α-glucosidase was studied by enzyme kinetic, circular dichroism spectra, fluorescence quenching, and molecular docking. Sucrose loading test in vivo further demonstrated that it could decrease blood glucose levels after sucrose administration in normal Kunming mice. In vitro cytotoxicity showed that 4 exhibited low cytotoxicity against normal human cell lines. The ADME study suggested that all compounds are likely to be orally active as they obeyed Lipinski’s rule of five. In summary, our studies showed that these derivatives are a new class of α-glucosidase inhibitors.     

Heterodimers of Histidine and Amantadine as Inhibitors for Wild Type and Mutant M2 Channels of Influenza A

Inhibitors bearing the imidazole, adamantane and related structures were synthesized and tested against WT, S31N and S31N‐L26I mutant M2 channels. Although amantadine ( 1 ) only inhibited WT M2 channel, compound 6 containing the imidazole and adamantane groups showed good inhibitory activity to WT and mutant M2 channels. The stereochemistry and basic pK_a of α‐amine are important for the activity of inhibitors and our data showed that derivatives of natural histidine are more active for M2 channels than those of unnatural histidine. The significance of our present results is that we have established a prospective strategy of drug discovery of WT and mutant M2 channels against influenza A.     

Four New Anthraquinones with Histone Deacetylase Inhibitory Activity from Ventilago denticulata Roots

Chromatographic separation of the crude extracts from the roots of Ventilago denticulata led to the isolation of four new anthraquinones, ventilanones L–O (1–4), together with eight known anthraquinones (5–12). Their structures were elucidated by spectroscopic methods (UV, IR, ¹H NMR, ¹³C NMR, and 2D NMR) and mass spectrometry (MS), as well as comparison of their spectroscopic data with those reported in the literature. HDACs inhibitory activity evaluation resulted that compound 2 exhibited moderate antiproliferative activity against HeLa and A549 cell lines but nontoxic to normal cell. Molecular docking indicated the phenolic functionality of 2 plays crucial interactions with class II HDAC4 enzyme.     

A bioactive new protostane-type triterpenoid from Alisma plantago-aquatica subsp. orientale (Sam.) Sam.

A new protostane-type triterpenoid, 5β,29-dihydroxy alisol A (1) was isolated from Alisma plantago-aquatica subsp. orientale (Sam.) Sam. as well as 12-deoxyphorbol-13α-pentadecanoate (2). We first report the presence of compound 2 in the genus Alisma. Their structures were established on the basis of 1D and 2D NMR, and HRESIMS spectroscopic analyses. All the isolated compounds were assayed for their inhibitory effects against human carboxylesterase 2 (HCE-2). Compounds 1 and 2 displayed inhibitory activities against HCE-2 with IC₅₀ values of 29.2 and 4.6 μM, respectively. The interaction mechanisms of HCE-2 with compounds 1 and 2 were investigated by molecular docking, respectively.     

Synthesis of 2-substituted endo-hymenialdisine derivatives

The first synthesis of 2-substituted endo-hymenialdisine derivatives 1-4 is described started with 2-substituted pyrroles and 5-substituted pyrrolo-2-carboxylic acids.     

Design,Synthesis and Biological Evaluation of Novel Pyrazolo[1,2,4]triazolopyrimidine Derivatives as Potential Anticancer Agents

Three novel pyrazolo-[4,3-e][1,2,4]triazolopyrimidine derivatives (1, 2, and 3) were designed, synthesized, and evaluated for their in vitro biological activity. All three compounds exhibited different levels of cytotoxicity against cervical and breast cancer cell lines. However, compound 1 showed the best antiproliferative activity against all tested tumor cell lines, including HCC1937 and HeLa cells, which express high levels of wild-type epidermal growth factor receptor (EGFR). Western blot analyses demonstrated that compound 1 inhibited the activation of EGFR, protein kinase B (Akt), and extracellular signal-regulated kinase (Erk)1/2 in breast and cervical cancer cells at concentrations of 7 and 11 µM, respectively. The results from docking experiments with EGFR suggested the binding of compound 1 at the ATP binding site of EGFR. Furthermore, the crystal structure of compound 3 (7-(4-bromophenyl)-9-(pyridin-4-yl)-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine) was determined by single crystal X-ray analysis. Our work represents a promising starting point for the development of a new series of compounds targeting EGFR.     

Discovery of Novel 2,4-Dianilinopyrimidine Derivatives Containing 4-(Morpholinomethyl)phenyl and N-Substituted Benzamides as Potential FAK Inhibitors and Anticancer Agents

Focal adhesion kinase (FAK) is responsible for the development and progression of various malignancies. With the aim to explore novel FAK inhibitors as anticancer agents, a series of 2,4-dianilinopyrimidine derivatives 8a–8i and 9a–9g containing 4-(morpholinomethyl)phenyl and N-substituted benzamides have been designed and synthesized. Among them, compound 8a displayed potent anti-FAK activity (IC₅₀ = 0.047 ± 0.006 μM) and selective antiproliferative effects against H1975 (IC₅₀ = 0.044 ± 0.011 μM) and A431 cells (IC₅₀ = 0.119 ± 0.036 μM). Furthermore, compound 8a also induced apoptosis in a dose-dependent manner, arresting the cells in S/G2 phase and inhibiting the migration of H1975 cells, all of which were superior to those of TAE226. The docking analysis of compound 8a was performed to elucidate its possible binding modes with FAK. These results established 8a as our lead compound to be further investigated as a potential FAK inhibitor and anticancer agent.     

Design,Synthesis and Cytotoxicity of Thiazole-Based Stilbene Analogs as Novel DNA Topoisomerase IB Inhibitors

A series of new thiazole-based stilbene analogs were designed, synthesized and evaluated for DNA topoisomerase IB (Top1) inhibitory activity. Top1-mediated relaxation assays showed that the synthesized compounds possessed variable Top1 inhibitory activity. Among them, (E)-2-(3-methylstyryl)-4-(4-fluorophenyl)thiazole (8) acted as a potent Top1 inhibitor with high Top1 inhibition of ++++ which is comparable to that of CPT. A possible binding mode of compound 8 with Top1–DNA complex was further provided by molecular docking. An MTT assay against human breast cancer (MCF-7) and human colon cancer (HCT116) cell lines revealed that the majority of these compounds showed high cytotoxicity, with IC₅₀ values at micromolar concentrations. Compounds 8 and (E)-2-(4-tert-butylstyryl)-4-(4-fluorophenyl)thiazole (11) exhibited the most potent cytotoxicity with IC₅₀ values of 0.78 and 0.62 μM against MCF-7 and HCT116, respectively. Moreover, the preliminary structure–activity relationships of thiazole-based stilbene analogs was also discussed.     

Synthesis and α-amylase inhibitory activity of glucose-deoxynojirimycin conjugates

Inhibitors of α-amylase have attracted attention for their putative effects against diabetes mellitus. Although numerous studies have explored natural small molecule inhibitors, acarbose is currently the only compound with sufficient inhibitory potency and drug-like characteristics to be considered as a potential therapeutic agent. We have synthesized conjugates of the potent glucosidase inhibitor, 1-deoxynojirimycin, and glucose, with the aim of enhancing inhibitory activity against α-amylase. This synthetic conjugate showed increased inhibition of α-amylase compared to 1-deoxynojirimycin alone, suggesting that similar modifications of existing glucosidase inhibitors may yield more potent α-amylase inhibitors.     

Preparation of (1R,1′R)-1,1′-(anthracene-9,10-diyl)bis(2,2,2-trifluoroethanamine): a chiral diamine with low basicity

A new chiral diamine with low basicity was synthesized in enantiopure form. (1R,1′R)-1,1′-(Anthracene-9,10-diyl)bis(2,2,2-trifluoroethanamine) was obtained by means of several stereochemically controlled reactions. The structures of the title compound and several intermediates were studied.     

The selectivity and promiscuity of brain-neuroregenerative inhibitors between ROCK1 and ROCK2 isoforms: An integration of SB-QSSR modelling,QM/MM analysis and in vitro kinase assay

The Rho-associated kinases (ROCKs) have long been recognized as an attractive therapeutic target for various neurological diseases; selective inhibition of ROCK1 and ROCK2 isoforms would result in distinct biological effects on neurogenesis, neuroplasticity and neuroregeneration after brain surgery and traumatic brain injury. However, the discovery and design of isoform-selective inhibitors remain a great challenge due to the high conservation and similarity between the kinase domains of ROCK1 and ROCK2. Here, a structure-based quantitative structure–selectivity relationship (SB-QSSR) approach was used to correlate experimentally measured selectivity with the difference in inhibitor binding to the two kinase isoforms. The resulting regression models were examined rigorously through both internal cross-validation and external blind validation; a nonlinear predictor was found to have high fitting stability and strong generalization ability, which was then employed to perform virtual screening against a structurally diverse, drug-like compound library. Consequently, five and seven hits were identified as promising candidates of 1-o-2 and 2-o-1 selective inhibitors, respectively, from which seven purchasable compounds were tested in vitro using a standard kinase assay protocol to determine their inhibitory activity against and selectivity between ROCK1 and ROCK2. The structural basis, energetic property and biological implication underlying inhibitor selectivity and promiscuity were also investigated systematically using a hybrid quantum mechanics/molecular mechanics (QM/MM) scheme.     

α-Fluoro Phosphonocarboxylates: the NMR Analysis of the Heteronuclear ABMX Spin System

Abstract

The α-fluorophosphonocarboxylate analogs of bisphosphonates have recently received attention due to their activity against Rab geranylgeranyl transferase, an enzyme implicated in a number of disease conditions. Most of the NMR data reported in the literature describing dialkyl α-fluorophosphonates are defined as first-order spectra. Here, we report a second-order pattern observed in ¹⁹F NMR spectrum, being a part of heteronuclear ABMX spin system. Such a spin system, CH₂C(F)P, was subjected to NMR analysis supported by iteration.