Design, Synthesis, and Pharmacological Evaluation of N-Acylhydrazones and Novel Conformationally Constrained Compounds as Selective and Potent Orally Active Phosphodiesterase-4 Inhibitors

Design, Synthesis, Experimental and Theoretical Characterization of a New Multitarget 2-Thienyl-N-Acylhydrazone Derivative

Pulmonary arterial hypertension (PAH) is a chronic cardiovascular disease that displays inflammatory components, which contributes to the difficulty of adequate treatment with the available therapeutic arsenal. In this context, the N-acylhydrazone derivative LASSBio-1359 was previously described as a multitarget drug candidate able to revert the events associated with the progression of PAH in animal models. However, in spite of having a dual profile as PDE4 inhibitor and adenosine A_2A receptor agonist, LASSBio-1359 does not present balanced potencies in the modulation of these two targets, which difficult its therapeutic use. In this paper, we describe the design concept of LASSBio-1835, a novel structural analogue of LASSBio-1359, planned by exploiting ring bioisosterism. Using X-ray powder diffraction, calorimetric techniques, and molecular modeling, we clearly indicate the presence of a preferred synperiplanar conformation at the amide function, which is fixed by an intramolecular 1,5-N∙∙∙S σ-hole intramolecular interaction. Moreover, the evaluation of LASSBio-1835 (4) as a PDE4 inhibitor and as an A_2A agonist confirms it presents a more balanced dual profile, being considered a promising prototype for the treatment of PAH.

Potent immunosuppressive activity of a phosphodiesterase-4 inhibitor N-acylhydrazone in models of lipopolysaccharide-induced shock and delayed-type hypersensitivity reaction

Immunosuppressive drugs are widely used for the treatment of immune-mediated diseases and inflammation, but the toxicity and side effects of the available immunosuppressors make the search of new agents of great relevance. Here, we evaluated the immunomodulatory activity of an N-acylhydrazone derivative, (E)-N'-(3,4-dimethoxybenzylidene)-4-methoxybenzohydrazide (LASSBio-1386), a phosphodiesterase-4 (PDE-4) inhibitor. LASSBio-1386 inhibited lymphocyte activation in a concentration-dependent fashion, decreasing lymphoproliferation and IFN-γ and IL-2 production stimulated by anti-CD3/CD28 mAbs or concanavalin A (Con A) and inducing cell-cycle arrest in the G0/G1 phase. These effects were not blocked by RU486, a glucocorticoid receptor (GR) antagonist, indicating an effect independent of glucocorticoid receptor activation. Combination index-isobologram analysis indicates a synergistic effect between LASSBio-1386 and dexamethasone in lymphoproliferation inhibition. LASSBio-1386 presented immunomodulatory action in macrophage cultures, as observed by a significant and concentration-dependent decrease in NO and TNF-α production, an effect achieved by reducing IĸB expression and NF-κB activation. In the mouse model of endotoxic shock, LASSBio-1386 at 50 and 100 mg/kg protected 50 and 85% of mice against LPS-induced lethality, respectively. In agreement to its in vitro action, treatment with 100 mg/kg of LASSBio-1386 reduced TNF-α and IL-1β serum levels, while increased IL-6 and IL-10. Finally, LASSBio-1386 reduced the paw edema in a BSA-induced delayed-type hypersensitivity model. These findings demonstrate the immunomodulatory and immunosuppressant effects of LASSBio-1386 and indicate this molecule is a promising pharmacologic agent for immune-mediated diseases.

Synthesis, Structure, Chemical Stability, and In Vitro Cytotoxic Properties of Novel Quinoline-3-Carbaldehyde Hydrazones Bearing a 1,2,4-Triazole or Benzotriazole Moiety

A small library of novel quinoline-3-carbaldehyde hydrazones (Series 1), acylhydrazones (Series 2), and arylsulfonylhydrazones (Series 3) bearing either a 1,2,4-triazole or benzotriazole ring at position 2 was prepared, characterized by elemental analyses and IR, NMR, and MS spectra, and then subjected to in vitro cytotoxicity studies on three human tumor cell lines: DAN-G, LCLC-103H, and SISO. In general, compounds 4, 6, and 8 substituted with a 1,2,4-triazole ring proved to be inactive, whereas the benzotriazole-containing quinolines 5, 7, and 9 elicited pronounced cancer cell growth inhibitory effects with IC50 values in the range of 1.23⁻7.39 µM. The most potent 2-(1H-benzotriazol-1-yl)-3-[2-(pyridin-2-yl)hydrazonomethyl]quinoline (5e) showed a cytostatic effect on the cancer cell lines, whereas N′-[(2-(1H-benzotriazol-1-yl)quinolin-3-yl)methylene]-benzohydrazide (7a) and N′-[(2-1H-benzotriazol-1-yl)quinolin-3-yl)methylene]-naphthalene-2-sulfonohydrazide (9h) exhibited selective activity against the pancreas cancer DAN-G and cervical cancer SISO cell lines. Based on the determined IC50 values, the compound 5e seems to be leading compound for further development as anticancer agent.

Phenylpyridine-2-ylguanidines and rigid mimetics as novel inhibitors of TNFα overproduction: Beneficial action in models of neuropathic pain and of acute lung inflammation

4-phenylpyridin-2-yl-guanidine (5b): a new inhibitor of the overproduction of pro-inflammatory cytokines (TNFα and Il1β) was identified from a high-throughput screening of a chemical library on human peripheral blood mononuclear cells (PBMCs) after LPS stimulation. Derivatives, homologues and rigid mimetics of 5b were designed and synthesized, and their cytotoxicity and ability to inhibit TNFα overproduction were evaluated. Among them, compound 5b and its mimetic 12 (2-aminodihydroquinazoline) showed similar inhibitory activities, and were evaluated in vivo in models of lung inflammation and neuropathic pain in mice. In particular, compound 12 proved to be active (5 mg/kg, ip) in both models.

Synthesis and biological evaluation of pyridazinone derivatives as potential anti-inflammatory agents

Cyclic nucleotide phosphodiesterase type 4 (PDE4), that controls intracellular level of cyclic nucleotide cAMP, has aroused scientific attention as a suitable target for anti-inflammatory therapy in respiratory diseases. Here we describe the development of two families of pyridazinone derivatives as potential PDE4 inhibitors and their evaluation as anti-inflammatory agents. Among these derivatives, 4,5-dihydropyridazinone representatives possess promising activity, selectivity towards PDE4 isoenzymes and are able to reduce IL-8 production by human primary polymorphonuclear cells.

Synthesis of azulene-substituted benzofurans and isocoumarins via intramolecular cyclization of 1-ethynylazulenes, and their structural and optical properties

The preparation of azulene-substituted benzofurans and isocoumarins was established by two types of intramolecular cyclization reaction of 1-ethynylazulenes.

LASSBio-897 Reduces Lung Injury Induced by Silica Particles in Mice: Potential Interaction with the A2A Receptor

Silicosis is a lethal fibro-granulomatous pulmonary disease highly prevalent in developing countries, for which no proper therapy is available. Among a small series of N-acylhydrazones, the safrole-derived compound LASSBio-897 (3-thienylidene-3, 4-methylenedioxybenzoylhydrazide) raised interest due to its ability to bind to the adenosine A_2A receptor. Here, we evaluated the anti-inflammatory and anti-fibrotic potential of LASSBio-897, exploring translation to a mouse model of silicosis and the A_2A receptor as a site of action. Pulmonary mechanics, inflammatory, and fibrotic changes were assessed 28 days after intranasal instillation of silica particles in Swiss–Webster mice. Glosensor cAMP HEK293G cells, CHO cells stably expressing human adenosine receptors and ligand binding assay were used to evaluate the pharmacological properties of LASSBio-897 in vitro. Molecular docking studies of LASSBio-897 were performed using the genetic algorithm software GOLD 5.2. We found that the interventional treatment with the A_2A receptor agonist CGS 21680 reversed silica particle-induced airway hyper-reactivity as revealed by increased responses of airway resistance and lung elastance following aerosolized methacholine. LASSBio-897 (2 and 5 mg/kg, oral) similarly reversed pivotal lung pathological features of silicosis in this model, reducing levels of airway resistance and lung elastance, granuloma formation and collagen deposition. In competition assays, LASSBio-897 decreased the binding of the selective A_2A receptor agonist [³H]-CGS21680 (IC₅₀ = 9.3 μM). LASSBio-897 (50 μM) induced modest cAMP production in HEK293G cells, but it clearly synergized the cAMP production by adenosine in a mechanism sensitive to the A_2A antagonist SCH 58261. This synergism was also seen in CHO cells expressing the A_2A, but not those expressing A_2B, A₁ or A₃ receptors. Based on the evidence that LASSBio-897 binds to A_2A receptor, molecular docking studies were performed using the A_2A receptor crystal structure and revealed possible binding modes of LASSBio-897 at the orthosteric and allosteric sites. These findings highlight LASSBio-897 as a lead compound in drug development for silicosis, emphasizing the role of the A_2A receptor as its putative site of action.

15-Deoxy-Delta-12,14-Prostaglandin J2 Inhibits Lung Inflammation and Remodeling in Distinct Murine Models of Asthma

15-deoxy-Δ-12,14-prostaglandin J₂ (15d-PGJ₂) has been described as an anti-inflammatory lipid mediator in several in vitro and in vivo studies, but its effect on allergic pulmonary inflammation remains elusive. The aim of this study was to investigate the therapeutic potential of 15d-PGJ₂ based on distinct murine models of allergic asthma triggered by either ovalbumin (OVA) or house dust mite extract (HDM). Characteristics of lung inflammation, airway hyper-reactivity (AHR), mucus exacerbation, and lung remodeling in sensitized A/J mice treated or not with 15d-PGJ₂ were assessed. 15d-PGJ₂ treatments were carried out systemically or topically given via subcutaneous injection or intranasal instillation, respectively. Analyses were carried out 24 h after the last allergen provocation. Irrespective of the route of administration, 15d-PGJ₂ significantly inhibited the peribronchial accumulation of eosinophils and neutrophils, subepithelial fibrosis and also mucus exacerbation caused by either OVA or HDM challenge. The protective effect of 15d-PGJ₂ occurred in parallel with inhibition of allergen-induced AHR and lung tissue production of pro-inflammatory cytokines, such as interleukin (IL)-5, IL-13, IL-17, and TNF-α. Finally, 15d-PGJ₂ was found effective in inhibiting NF-κB phosphorylation upon HDM challenge as measured by Western blotting. In conclusion, our findings suggest that 15d-PGJ₂ can reduce crucial features of asthma, including AHR, lung inflammation, and remodeling in distinct murine models of the disease. These effects are associated with a decrease in lung tissue generation of pro-inflammatory cytokines by a mechanism related to downregulation of NF-κB phosphorylation.

α-bisabolol-loaded lipid-core nanocapsules reduce lipopolysaccharide-induced pulmonary inflammation in mice

Acute respiratory distress syndrome (ARDS) is a severe clinical condition of respiratory failure due to an intense inflammatory response with different etiologies. Despite all efforts, therapy remains limited, and ARDS is still associated with high mortality and morbidity. Plants can provide a vast source of active natural products for the discovery of new drugs. α-bisabolol (α-bis), a constituent of the essential oil from chamomile, has elicited pharmacological interest. However, the molecule has some limitations to its biological application. This study was conducted to develop a drug delivery system using lipid-core nanocapsules (LNCs) to improve the anti-inflammatory effects of orally administered α-bis. α-bis-loaded LNCs (α-bis-LNCs) were prepared by interfacial deposition of poly(ε-caprolactone) and orally administered in a mouse model of ARDS triggered by an intranasal administration of lipopolysaccharide (LPS). We found that α-bis-LNCs (30, 50, and 100 mg kg^-1) significantly reduced airway hyperreactivity (AHR), neutrophil infiltration, myeloperoxidase activity, chemokine levels (KC and MIP-2), and tissue lung injury 18 hours after the LPS challenge. By contrast, free α-bis failed to modify AHR and neutrophil accumulation in the bronchoalveolar lavage effluent and lung parenchyma and inhibited elevation in the myeloperoxidase and MIP-2 levels only at the highest dose. Furthermore, only α-bis-LNCs reduced LPS-induced changes in mitogen-activated protein kinase signaling, as observed by a significant reduction in phosphorylation levels of ERK1/2, JNK, and p38 proteins. Taken together, our results clearly show that by using LNCs, α-bis was able to decrease LPS-induced inflammation. These findings may be explained by the robust increase of α-bis concentration in the lung tissue that was achieved by the LNCs. Altogether, these results indicate that α-bis-LNCs should further be investigated as a potential alternative for the treatment of ARDS.

New piperidine-hydrazone derivatives: Synthesis, biological evaluations and molecular docking studies as AChE and BChE inhibitors

Hydrazones and the piperidine ring containing compounds were considered as beneficial substrates in drug design. Therefore, this study was aimed at the synthesis of new benzoyl hydrazones derived from ethyl 4-oxopiperidine-1-carboxylate and 2,6-diphenylpiperidin-4-one. The synthesized compounds (1-19) were screened for their antioxidant, anticholinesterase and anticancer activities. The antioxidant capacity of the compounds was evaluated by using four complementary tests. The results showed that compound 7 and 17 have the higher lipid peroxidation inhibitory activity than the other compounds. In DPPH˙ scavenging assay, compounds 5, 6, 10, 14, 17 demonstrated better activity than that of standard BHT, while in ABTS⁺˙ scavenging assay compound 6 and 17 exhibited better activity among the other compounds. The CUPRAC assay disclosed that compound 2 displayed better activity than α-tocopherol. The anticholinesterase activity was performed against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Compound 11 (IC₅₀: 35.30 ± 1.11 μM) inhibited BChE better than galantamine (IC₅₀: 46.03 ± 0.14 μM). We conclude that the compound 11 can be considered as a candidate for BChE inhibitor. Moreover docking method was applied to elucidate the AChE and BChE inhibitory mechanism of the compound 11. Molecular docking analysis revealed that compound 11 bound to BChE enzyme more efficiently when compared to the AChE due to its orientations and different types of interactions. In addition, the non-cytotoxic properties of the compounds brought them into prominence, although they did not show significant anticancer properties.

Treatment with Adenosine Receptor Agonist Ameliorates Pain Induced by Acute and Chronic Inflammation

Rheumatoid arthritis is an inflammatory autoimmune condition, and tumor necrosis factor-α (TNF-α) plays an important role in its pathophysiology. In vitro, (E)-N'-(3,4-dimethoxybenzylidene)-N-methylbenzohydrazide (LASSBio-1359) has exhibited anti-TNF-α properties, and in vivo these effects are mediated via activation of adenosine receptor. This work investigates the antinociceptive action of LASSBio-1359 in murine models of acute and chronic inflammatory pain. Male mice received an intraperitoneal injection of LASSBio-1359 and then were evaluated in formalin- and carrageenan-induced paw edema assays. Complete Freund's adjuvant (CFA) was used to induce a mouse model of monoarthritis. These mice were treated with LASSBio-1359 by oral gavage to evaluate thermal and mechanical hyperalgesia. TNF-α and inducible nitric oxide synthase (iNOS) expression as well as histologic features were analyzed. The time of reactivity to formalin in the neurogenic phase was reduced from 56.3 ± 6.0 seconds to 32.7 ± 2.2 seconds and 23.8 ± 2.6 seconds after treatment with LASSBio-1359 at doses of 10 mg/kg and 20 mg/kg, respectively. A reversal of the antinociceptive action of LASSBio-1359 was observed in the inflammatory phase after treatment with ZM 241385 [4-(2-[7-amino-2-(2-furly)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol], an adenosine A2A antagonist. Carrageenan-induced thermal and mechanical hyperalgesia were reduced after treatment with LASSBio-1359. Similarly, CFA-induced thermal and mechanical hyperalgesia were reduced after treatment with LASSBio-1359 (25 and 50 mg/kg). Levels of TNF-α and iNOS expression increased in the monoarthritis model and were normalized in animals treated with LASSBio-1359, which was also associated with beneficial effects in the histologic analysis. These results suggest that LASSBio-1359 represents an alternative treatment of monoarthritis.

Potential of PEGylated Toll-Like Receptor 7 Ligands for Controlling Inflammation and Functional Changes in Mouse Models of Asthma and Silicosis

Prior investigations show that signaling activation through pattern recognition receptors can directly impact a number of inflammatory lung diseases. While toll-like receptor (TLR) 7 agonists have raised interest for their ability to inhibit allergen-induced pathological changes in experimental asthma conditions, the putative benefit of this treatment is limited by adverse effects. Our aim was to evaluate the therapeutic potential of two PEGylated purine-like compounds, TMX-302 and TMX-306, characterized by TLR7 partial agonistic activity; therefore, the compounds are expected to induce lower local and systemic adverse reactions. In vitro approaches and translation to murine models of obstructive and restrictive lung diseases were explored. In vitro studies with human PBMCs showed that both TMX-302 and TMX-306 marginally affects cytokine production as compared with equivalent concentrations of the TLR7 full agonist, TMX-202. The PEGylated compounds did not induce monocyte-derived DC maturation or B cell proliferation, differently from what observed after stimulation with TMX-202. Impact of PEGylated ligands on lung function and inflammatory changes was studied in animal models of acute lung injury, asthma, and silicosis following Lipopolysaccharide (LPS), allergen (ovalbumin), and silica inhalation, respectively. Subcutaneous injection of TMX-302 prevented LPS- and allergen-induced airway hyper-reactivity (AHR), leukocyte infiltration, and production of pro-inflammatory cytokines in the lung. However, intranasal instillation of TMX-302 led to neutrophil infiltration and failed to prevent allergen-induced AHR, despite inhibiting leukocyte counts in the BAL. Aerosolized TMX-306 given prophylactically, but not therapeutically, inhibited pivotal asthma features. Interventional treatment with intranasal instillation of TMX-306 significantly reduced the pulmonary fibrogranulomatous response and the number of silica particles in lung interstitial space in silicotic mice. These findings highlight the potential of TMX-306, emphasizing its value in drug development for lung diseases, and particularly silicosis.

Design, Synthesis, and Pharmacological Evaluation of Novel N-Acylhydrazone Derivatives as Potent Histone Deacetylase 6/8 Dual Inhibitors

This manuscript describes a novel class of N-acylhydrazone (NAH) derivatives that act as histone deacetylase (HDAC) 6/8 dual inhibitors and were designed from the structure of trichostatin A (1). Para-substituted phenyl-hydroxamic acids presented a more potent inhibition of HDAC6/8 than their meta analogs. In addition, the effect of compounds (E)-4-((2-(4-(dimethylamino)benzoyl)hydrazono)methyl)-N-hydroxybenzamide (3c) and (E)-4-((2-(4-(dimethylamino)benzoyl)-2-methylhydrazono)methyl)-N-hydroxybenzamide (3f) on the acetylation of α-tubulin revealed an increased level of acetylation. These two compounds also affected cell migration, indicating their inhibition of HDAC6. An analysis of the antiproliferative activity of these compounds, which presented the most potent activity, showed that compound 3c induced cell cycle arrest and 3g induced apoptosis through caspase 3/7 activation. These results suggest HDAC6/8 as a potential target of future molecular therapies for cancer.

Phenyliodonium diacetate mediated carbotrifluoromethylation of N-acylhydrazones

A concise, efficient and direct trifluoromethylation method of aldehyde-derived N-acylhydrazones has been firstly developed by using the combination of inexpensive, stable and commercially available TMSCF₃ and PhI(OAc)₂ as the CF₃ source under mild reaction conditions.

Microwave-assisted synthesis and photophysical studies of novel fluorescent N-acylhydrazone and semicarbazone-7-OH-coumarin dyes

Emissive 7-OH-coumarins were synthesized by a microwave-assisted protocol and spectral changes were induced after conformational changes in low polarity media.

Antiplasmodial and anti-inflammatory effects of an antimalarial remedy from the Wayana Amerindians, French Guiana: takamalaimë (Psidium acutangulum Mart. ex DC., Myrtaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Field investigations highlighted the use of Psidium acutangulum Mart. ex DC (syn. P. persoonii McVaugh), a small tree used by the Wayana Amerindians in Twenke-Taluhwen and Antecume-Pata, French Guiana, for the treatment of malaria, and administered either orally in the form of a decoction or applied externally over the whole body. This use appears limited to the Wayana cultural group in French Guiana and has never been reported anywhere else. Our goal was to evaluate the antimalarial and anti-inflammatory activities of a P. acutangulum decoction to explain the good reputation of this remedy.

MATERIALS AND METHODS

Interviews with the Wayana inhabitants of Twenke-Taluhwen and Antecume-Pata were conducted within the TRAMAZ project according to the TRAMIL methodology, which is based on a quantitative and qualitative analysis of medicinal plant uses. A decoction of dried aerial parts of P. acutangulum was prepared in consistency with the Wayana recipe. In vitro antiplasmodial assays were performed on chloroquine-resistant FcB1 ([(3)H]-hypoxanthine bioassay) and 7G8 (pLDH bioassay) P. falciparum strains and on chloroquine sensitive NF54 ([(3)H]-hypoxanthine bioassay) P. falciparum strain. In vitro anti-inflammatory activity (IL-1β, IL-6, IL-8, TNFα) was evaluated on LPS-stimulated human PBMC and NO secretion inhibition was measured on LPS stimulated RAW murine macrophages. Cytotoxicity of the decoction was measured on L6 mammalian cells, PBMCs, and RAW cells. A preliminary evaluation of the in vivo antimalarial activity of the decoction, administered orally twice daily, was assessed by the classical four-day suppressive test against P. berghei NK65 in mice.

RESULTS

The decoction displayed a good antiplasmodial activity in vitro against the three tested strains, regardless to the bioassay used, with IC50 values of 3.3µg/mL and 10.3µg/mL against P. falciparum FcB1 and NF54, respectively and 19.0µg/mL against P. falciparum 7G8. It also exhibited significant anti-inflammatory activity in vitro in a dose dependent manner. At a concentration of 50µg/mL, the decoction inhibited the secretion of the following pro-inflammatory cytokines: TNFα (-18%), IL-1β (-58%), IL-6 (-32%), IL-8 (-21%). It also exhibited a mild NO secretion inhibition (-13%) at the same concentration. The decoction was non-cytotoxic against L6 cells (IC50>100µg/mL), RAW cells and PBMC. In vivo, 150µL of the decoction given orally twice a day (equivalent to 350mg/kg/day of dried extract) inhibited 39.7% average parasite growth, with more than 50% of inhibition in three mice over five. The absence of response for the two remaining mice, however, induced a strong standard deviation.

CONCLUSIONS

This study highlighted the in vitro antiplasmodial activity of the decoction of P. acutangulum aerial parts, used by Wayana Amerindians from the Upper-Maroni in French Guiana in case of malaria. Its antioxidant and anti-inflammatory potential, which may help to explain its use against this disease, was demonstrated using models of artificially stimulated cells.

Beneficial effects of a novel agonist of the adenosine A2A receptor on monocrotaline-induced pulmonary hypertension in rats

BACKGROUND AND PURPOSE

Pulmonary arterial hypertension (PAH) is characterized by enhanced pulmonary vascular resistance, right ventricular hypertrophy and increased right ventricular systolic pressure. Here, we investigated the effects of a N-acylhydrazone derivative, 3,4-dimethoxyphenyl-N-methyl-benzoylhydrazide (LASSBio-1359), on monocrotaline (MCT)-induced pulmonary hypertension in rats.

EXPERIMENTAL APPROACH

PAH was induced in male Wistar rats by a single i.p. injection of MCT (60 mg·kg(-1)) and 2 weeks later, oral LASSBio-1359 (50 mg·kg(-1)) or vehicle was given once daily for 14 days. Echocardiography was used to measure cardiac function and pulmonary artery dimensions, with histological assay of vascular collagen. Studies of binding to human recombinant adenosine receptors (A1, A2A, A3) and of docking with A2A receptors were also performed.

KEY RESULTS

MCT administration induced changes in vascular and ventricular structure and function, characteristic of PAH. These changes were reversed by treatment with LASSBio-1359. MCT also induced endothelial dysfunction in pulmonary artery, as measured by diminished relaxation of pre-contracted arterial rings, and this dysfunction was reversed by LASSBio-1359. In pulmonary artery rings from normal Wistar rats, LASSBio-1359 induced relaxation, which was decreased by the adenosine A2A receptor antagonist, ZM 241385. In adenosine receptor binding studies, LASSBio-1359 showed most affinity for the A2A receptor and in the docking analyses, binding modes of LASSBio-1359 and the A2A receptor agonist, CGS21680, were very similar.

CONCLUSION AND IMPLICATIONS

In rats with MCT-induced PAH, structural and functional changes in heart and pulmonary artery were reversed by treatment with oral LASSBio-1359, most probably through the activation of adenosine A2A receptors.

Development of novel Asf1-H3/H4 inhibitors

The histone chaperone anti-silencing function 1 (Asf1) has emerged as a promising target for therapeutic intervention for multiple cancers (Cell2006, 127, 458). Asf1 is involved in the packaging of the eukaryotic genome into chromatin, which is essential for normal growth, development, and differentiation, as this regulates all nuclear processes that use DNA as a substrate. Starting from a collection of HTS leads, we identified a series of N-acyl hydrazones as novel inhibitors of the Asf-histone H3/H4 interaction. These compounds represent the first example of inhibitors capable of disrupting the Asf1-H3/H4 complex.

Synthesis, biological evaluation, and molecular docking studies of novel 2-styryl-5-nitroimidazole derivatives containing 1,4-benzodioxan moiety as FAK inhibitors with anticancer activity

A series of 2-styryl-5-nitroimidazole derivatives containing 1,4-benzodioxan moiety (3a-3r) has been designed, synthesized and their biological activities were also evaluated as potential antiproliferation and focal adhesion kinase (FAK) inhibitors. Among all the compounds, 3p showed the most potent activity in vitro which inhibited the growth of A549 with IC50 value of 3.11 μM and Hela with IC50 value of 2.54 μM respectively. Compound 3p also exhibited significant FAK inhibitory activity (IC50=0.45 μM). Docking simulation was performed for compound 3p into the FAK structure active site to determine the probable binding model.

3-substituted indazoles as configurationally locked 4EGI-1 mimetics and inhibitors of the eIF4E/eIF4G interaction

4EGI-1, the prototypic inhibitor of eIF4E/eIF4G interaction, was identified in a high-throughput screening of small-molecule libraries with the aid of a fluorescence polarization assay that measures inhibition of binding of an eIF4G-derived peptide to recombinant eIF4E. As such, the molecular probe 4EGI-1 has potential for the study of molecular mechanisms involved in human disorders characterized by loss of physiological restraints on translation initiation. A hit-to-lead optimization campaign was carried out to overcome the configurational instability in 4EGI-1, which stems from the E-to-Z isomerization of the hydrazone function. We identified compound 1 a, in which the labile hydrazone was incorporated into a rigid indazole scaffold, as a promising rigidified 4EGI-1 mimetic lead. In a structure-activity relationship study directed towards probing the structural latitude of this new chemotype as an inhibitor of eIF4E/eIF4G interaction and translation initiation we identified 1 d, an indazole-based 4EGI-1 mimetic, as a new and improved lead inhibitor of eIF4E/eIF4G interaction and a promising molecular probe candidate for elucidation of the role of cap-dependent translation initiation in a host of pathophysiological states.

Preparation of highly substituted (β-acylamino)acrylates via iron-catalyzed alkoxycarbonylation of N-vinylacetamides with carbazates

A simple and efficient iron-catalyst system was applied for the synthesis of various (β-acylamino)acrylate derivatives under mild reaction conditions.

N-2-Hydroxybenzaldehyde acylhydrazone–Fe(iii) complex: synthesis, crystal structure and its efficient and selective N-methylation

The n-acylhydrazone–Fe(iii) complexes permit ligand's amide N to be easily methylated and suppress the O-methylation side reactions of phenol.

Lead optimization of an acylhydrazone scaffold possessing antiviral activity against Lassa virus

Previously we reported the optimization of antiviral scaffolds containing benzimidazole and related heterocycles possessing activity against a variety of arenaviruses. These series of compounds were discovered through an HTS campaign of a 400,000 small molecule library using lentivirus-based pseudotypes incorporated with the Lassa virus envelope glycoprotein (LASV GP). This screening also uncovered an alternate series of very potent arenavirus inhibitors based upon an acylhydrazone scaffold. Subsequent SAR analysis of this chemical series involved various substitutions throughout the chemical framework along with assessment of the preferred stereochemistry. These studies led to an optimized analog (ST-161) possessing subnanomolar activity against LASV and submicromolar activity against a number of other viruses in the Arenaviridae family.

Characterization of amide bond conformers for a novel heterocyclic template of N-acylhydrazone derivatives

Herein we describe NMR experiments and structural modifications of 4-methyl-2-phenylpyrimidine-N-acylhydrazone compounds (aryl-NAH) in order to discover if duplication of some signals in their ¹H- and ¹³C-NMR spectra was related to a mixture of imine double bond stereoisomers (E/Z) or CO-NH bond conformers (syn and anti-periplanar). NMR data from NOEdiff, 2D-NOESY and ¹H-NMR spectra at different temperatures, and also the synthesis of isopropylidene hydrazone revealed the nature of duplicated signals of a 4-methyl-2-phenylpyrimidine-N-acylhydrazone derivative as a mixture of two conformers in solution. Further we investigated the stereoelectronic influence of substituents at the ortho position on the pyrimidine ring with respect to the carbonyl group, as well as the electronic effects of pyrimidine by changing it to phenyl. The conformer equilibrium was attributed to the decoplanarization of the aromatic ring and carbonyl group (generated by an ortho-alkyl group) and/or the electron withdrawing character of the pyrimidine ring. Both effects increased the rotational barrier of the C-N amide bond, as verified by the ΔG^≠ values calculated from dynamic NMR. As far as we know, it is the first description of aryl-NAH compounds presenting two CO-NH bond- related conformations.