Novel pyrimidinone derivatives: synthesis, antitumor and antimicrobial evaluation

Starting from 6-aryl-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile (4a-d), a series of mono- and dialkyl derivatives 5a-j and 6a, b was synthesized. Hydrazinolysis of 4a, b, d and 5d afforded the hydrazino derivatives 7a-c which were cyclised to give the triazolopyrimidinones 8a-c and the pyrimidotriazinones 9a-c through the reaction with formic acid and chloroacetyl chloride, respectively. Most of the newly synthesized compounds were evaluated for their in-vitro antitumor activity. Compounds 6a and b displayed promising anticancer activity against leukaemia, non-small cell lung, melanoma, and renal cancer. On the other hand, all compounds prepared were screened for their in-vitro antibacterial and antifungal activities. Compounds 5h and j showed significant activity against Staphylococcus aureus, while compounds 5e, 7c and 8c displayed moderate inhibitory activity against Candida albicans.     

A convenient synthesis of 2-hydrazinoethylphosphonic acid and derivatives

2-Hydrazinoethylphosphonic acid was prepared using a simple procedure involving Michael addition of hydrazine hydrate to diethyl ethenylphosphonate, followed by hydrolysis with hydrochloric acid. The product was converted into five- and six-membered heterocycles.     

Novel deoxy-selenylconduritols: chemoenzymatic synthesis and biological evaluation

The first synthesis of two selenyldeoxycyclitols (4-bromo-2-phenylselenyl conduritol F and 6-phenylselenylconduritol F) is reported via a chemoenzymatic enantioselective route. The key step of the synthesis is the selenolysis of a vinyl epoxide. The new compounds were evaluated for their capacity to inhibit the growth of different microorganisms using a modification of the agar diffusion technique with thin layer chromatography plates as support.     

Dendrimer-based prodrugs: design, synthesis, screening and biological evaluation

Dendrimers are a new class of artificial macromolecules with well-defined hyperbranched structures which enable bio-active molecules such as drugs to be presented in a highly multi-valent fashion. Covalent conjugation of drugs to the surface of dendrimers can be easily achieved either by direct chemical reactions between dendrimers and drug molecules including esterification and amidation or through cleavable linkers, depending on the functional groups on the surface of dendrimers. The pharmacological properties of these dendrimer-based prodrugs such as biocompatibility, biodistribution, biostability, bioadhesion and biopermeability can be modulated by further modifying dendrimers with specific functional molecules to fit a specific medicinal purpose. In this mini-review, recent advances on the use of dendrimers as prodrug nano-scaffolds were briefly demonstrated. The design and synthesis of dendrimer-based prodrugs as well as screening their intrinsic properties in biological systems were fully discussed.     

New benzimidazole derivatives: Design,synthesis, docking,and biological evaluation

The aim of this study was to synthesize novel enaminonitrile derivatives starting from 2-aminobenzimidazole and utilize this derivative for the preparation of novel heterocyclic compounds and assess their function for biological activity screening. The key precursor N-(1H-benzo[d]imidazol-2-yl)carbonohydrazonoyl dicyanide (2) was prepared in pyridine by coupling of diazotized 2-aminobenzimidazole (1) with malononitrile. Compound 2 was subjected to react with various secondary amines such as piperidine, morpholine, piperazine, diphenylamine, N-methylglucamine, and diethanolamine in boiling ethanol to give the acrylonitriles (2Z)-2-((1H-benzo[d]imidazol-2-yl)diazenyl)-3-amino-3-(piperidin-1-yl)acrylonitrile (3), (2Z)-2-((1H-benzo[d]imidazol-2-yl)diazenyl)-3-amino-3-morpholinoacrylonitrile (4), (2Z)-2-((1H-benzo[d]imidazol-2-yl)diazenyl)-3-amino-3-(piperazin-1-yl)acrylonitrile (5), (2Z)-2-((1H-benzo[d]imidazol-2-yl)diazenyl)-3-amino-3-(diphenylamino)acrylonitrile (6), (2Z)-2-((1H-benzo[d]imidazol-2-yl)diazenyl)-3-amino-3-(methyl((2S,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl)amino)acrylonitrile (7), and (2Z)-2-((1H-benzo[d]imidazol-2-yl)diazenyl)-3-amino-3-(bis(2-hydroxyethyl)amino)acrylonitrile (8), respectively. It has been found that the behaviour of nitrile derivative 2 towards hydrazine hydrate to the creation of 4-((1H-benzo[d]imidazol-2-yl)diazenyl)-1H-pyrazole-3,5-diamine (9). The reaction of malononitrile with compound 2 in an ethanolic solution catalyzed with sodium ethoxide afforded 4-amino-1-(1H-benzo[d]imidazol-2-yl)-6-imino-1,6-dihydropyridazine-3,5-dicarbonitrile (11). Moreover, malononitrile reacted with 7 in a boiling ethanolic sodium ethoxide solution to give 2-(5-((1H-benzo[d]imidazol-2-yl)diazenyl)-4-amino-6-(methyl((2S,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl)amino)pyrimidin-2-yl)acetonitrile (14). Heating 7 in boiling acetic anhydride and pyridine afforded (2R,3R,4R,5S)-6-(((1E)-2-((1-acetyl-1H-benzo[d]imidazol-2-yl)diazenyl)-1-(N-acetylacetamido)-2-cyanovinyl)(methyl)amino)hexane-1,2,3,4,5-pentayl pentaacetate (15). When compound 15 is heated for a long time in refluxing DMF including a catalytic of TEA, cyclization occurs to give the corresponding (2R,3R,4R,5S)-6-((1-acetyl-3-((1-acetyl-1H-benzo[d]imidazol-2-yl)diazenyl)-4-amino-6-oxo-1,6-dihydropyridin-2-yl)(methyl)amino)hexane-1,2,3,4,5-pentayl pentaacetate (16). In addition, triethyl orthoformate was reacted with compound 7 in the presence of acetic anhydride to afford the corresponding ethoxymethyleneamino derivative (2R,3R,4R,5S)-6-(((1E)-2-((1-acetyl-1H-benzo[d]imidazol-2-yl)diazenyl)-2-cyano-1-(((E) ethoxymethylene)amino)vinyl)(methyl)amino)hexane-1,2,3,4,5-pentayl pentaacetate (17). Also, it has been found that heating a mixture of 7 with DMF/DMA in anhydrous xylene yielded compound (1E)-N'-((1E)-2-((1H-benzo[d]imidazol-2-yl)diazenyl)-2-cyano-1-(methyl((2S,3R,4R,5R)-2,3,4,5,6-pentahydroxyhexyl)amino)vinyl)-N,N-dimethylformimidamide (18). In addition, compound 7, when reacted with several acid anhydrides, allowed the matching phthalimide derivatives 19–26. The results showed that compound 14 has significantly higher ABTS and antitumor activities than the other compounds. Molecular modelling was also studied for compounds 22 and 24. The viability of four many cell lines—the African green monkey kidney epithelial cells (VERO), human breast adenocarcinoma cell line (MCF-7), human lung fibroblast cell line (WI-38), and human hepatocellular liver carcinoma cell line (HepG2) was examined to determine the antitumor activities of the newly synthesized compounds. Also, it was found that compounds 9, 11, 15, 16, 22, 23, 24 and 25 are strong against HepG2 cell lines, while 16, 22, and 25 are strong against WI-38 cell lines. Moreover, it was also found that compounds 16 and 22 are strong against VERO cell lines. On the other hand, compounds 7, 14, 15, 16, and 22 are strong while the rest of the other compounds are moderate against the MCF-7 cell line. The result of docking showed that compound 24 got stabilized inside the pocket with a very promising binding score of ? 8.12 through hydrogen bonds with Arg184 and Lys179, respectively.     

Calix[4]arene based 1,3,4-oxadiazole and thiadiazole derivatives: design, synthesis, and biological evaluation

In the present investigation, we describe some novel calixarene based heterocyclic compounds (5a-5i) in which 1,3,4-oxadiazole and 1,3,4-thiadiazole derivatives have been coupled with 5,11,17,23-tetra-tert-butyl-25,27-bis(chlorocarbonyl-methoxy)-26,28-dihydroxy calix[4]arene. All the newly synthesized calixarene based heterocyclic compounds have been characterized by elemental analysis and various spectroscopic methods like FTIR, (1)H NMR, (13)C NMR, and FAB-MS. All the final scaffolds have been subjected to antioxidant activity, in vitro antimicrobial screening against two gram (+ve) bacteria (S. aureus, S. pyogenes), two gram (-ve) bacteria (E. coli, P. aeruginosa) and two fungal strains (C. albicans, A. clavatus) and also have been screened for their antitubercular activity against Mycobacterium tuberculosis H(37)Rv.     

Novel benzothiazole, benzimidazole and benzoxazole derivatives as potential antitumor agents: synthesis and preliminary in vitro biological evaluation

In a previous hit-to-lead research program targeting anticancer agents, two promising lead compounds, 1a and 1b, were found. However, the poor solubility of 1a and 1b made difficult further in vivo studies. To solve this problem, a lead optimization was conducted through introducing N-methyl-piperazine groups at the 2-position and 6-position. To our delight, the optimized analogue 1d showed comparable antiproliferative activity in vitro with better solubility, compared with 1a. Based on this result, the replacement of the benzothiazole scaffold with benzimidazole and benzoxazole moieties afforded 1f and 1g, whose activities were fundamentally retained. In the preliminary in vitro biological evaluation, the immunofluorescence staining of HCT116 cells indicated that 1d, 1f and 1g led to cytosolic vacuolization which was not induced by 1a at low micromolecular concentrations. These results suggest that these optimized compounds might potentially constitute a novel class of anticancer agents, which merit further studies.     

Novel d-seco paclitaxel analogues: synthesis, biological evaluation, and model testing

Four new D-secopaclitaxel analogues were synthesized from paclitaxel. The key step of the synthesis involved the opening of the D-ring by Jones oxidation. Two of the compounds had been predicted to be nearly as active as paclitaxel in a minireceptor model of the binding site on tubulin, but all were biologically inactive in an in vitro cytotoxic assay and a tubulin assembly assay. The biological results identify a weakness in our predictive minireceptor model and suggest a corrective remedy in which additional amino acids are needed to accommodate ligand-protein steric effects around the oxetane ring. These changes to the model lead to correct predictions of the bioactivity. Conformational analysis and dynamics simulations of the compounds showed that the 4-acetyl substituent is as important as the oxetane in determining the A ring conformation.     

Novel 8-arylidenetetrahydroquinazoline N-oxides: synthesis,photophysical properties and biological evaluation

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氨基酸衍生物的反应、合成和生物活性研究

讨论了我们小组近年来以氨基酸衍生物为主线，在代谢型谷氨酸受体及蛋白激酶C有选择性的调节剂的发现和合成，在发展新反应以及天然产物合成方面所取得的一些结果。     

A convenient synthesis of dihydrocoumarins from phenols and cinnamic acid derivatives

A facile procedure for synthesis of dihydrocoumarin derivatives was described. Although the yield of the products in the reaction of phenols with acrylates in trifluoroacetic acid in the presence of Pd(OAc)₂ giving coumarins was found to be very low, dihydrocoumarin derivatives were obtained in good to high yields in the absence of Pd(OAc)₂ when ethyl cinnamates bearing electron-donating groups were employed in this reaction.     

Antioxidant activity of diphenylpropionamide derivatives: synthesis, biological evaluation and computational analysis

We report the synthesis, antioxidant and antiproliferative activity and a QSAR analysis of synthetic diphenylpropionamide derivatives. Synthesis of these compounds was achieved by direct condensation of 2,2- and 3,3-diphenylpropionic acid and appropriate amines using 1-propylphoshonic acid cyclic anhydride (PPAA) as catalyst. Compound structures were elucidated by NMR analysis and their melting points were measured. The in vitro antioxidant activity of these compounds was tested by evaluating the amount of scavenged ABTS radical and estimating ROS and NO production in LPS stimulated J774.A1 macrophages. All compounds were tested for their effect on viability of cells and results demonstrated that they are not toxic towards the cell lines used. The cytotoxic activity of all compounds was evaluated by a Brine Shrimp Test.     

Novel synthesis of zerumbone-pendant derivatives and their biological activity

Zerumbone 1, having powerful latent reactivity and containing two conjugated double bonds and a double conjugated carbonyl group is the major component of the essential oil of wild ginger, Zingiber zerumbet Smith. The conjugation system plays an important role in the expression of biological activity. N-Bromosuccinimide (NBS) reaction of 1 gave high reactive intermediate 2 with an exo-methylene group, which was obtained from 1 quantitatively. Treatment of 2 with nucleophiles gave various zerumbone-pendant derivatives, including C–H, C–O, C–N, and C–C bond formation, maintaining the conjugation system through S_N2′-type reaction. Almost all zerumbone-pendant derivatives showed a good value of IC₅₀ against the suppressive effect of NO generation. Among them, amine derivative 5, binding with 2 mol of zerumbone, showed the strongest activity (IC₅₀: 0.24 μM).     

Novel methyl helianthrones as photosensitizers: synthesis and biological evaluation

A combination of light, oxygen and a photosensitizer is used to induce death of cancer cells by photodynamic therapy. In this study, we have synthesized several new methyl helianthrone derivatives and compared their phototoxicity with that of hypericin. In contrast to hypericin, methyl helianthrones are soluble in aqueous solutions and have a broad range of light absorbance, which allows the use of polychromatic light. Structural modifications of methyl helianthrone demonstrated that substitution of hydrogen atoms of methyl helianthrone at Positions 2 and 5 with Br atoms or methylation of its phenolic hydroxyls, significantly increases the corresponding singlet oxygen quantum yield and their phototoxicity toward alphaT3-1, M2R and LNCaP cells. The phototoxicity of some of these compounds was similar to that of hypericin. Methyl helianthrones, like hypericin, accumulated mainly in the perinuclear region as evident by confocal microscopy. Irradiation of cells pretreated with methyl helianthrone derivatives generates intracellular reactive oxygen species and lipid free radicals, as shown by a fluorescentic probe and electron paramagnetic resonance methods, respectively. The phototoxicity of these methyl helianthrones as well as their ability to oxidize membrane lipids were significantly decreased on addition of specific Type-II inhibitors, suggesting the involvement of singlet oxygen as the main oxidant.     

Substituted-nicotinyl thiourea derivatives bearing pyrimidine moiety: synthesis and biological evaluation

A series of substituted-nicotinyl thiourea derivatives containing pyrimidine ring were synthesized in good to excellent yield using PEG-400 as solid?Cliquid phase transfer catalyst under ultrasonic irradiation. The structures of all newly synthesized compounds were elucidated and confirmed by IR, ¹H NMR and elemental analysis. The preliminary biological tests show that some of the target compounds present good inhibitory activities against the root and stalk of dicotyledon plants and are safe for monocotyledon plants.     

Target-based design,synthesis and biological activity of new pyrazole amide derivatives

Based on the similarities in the conformation of VS008 (N-(4-methylphenyl)-3-(tert-butyl)-1-(phenylmethyl)-1H-pyrazole-5-carboxamide) and BYIO6830 (N'-(3,5-dimethylbenzoyl)-N'-tert-butyl-5-methyl-2,3-dihydro-1,4-benzodioxine-6-carbohydrazide) bound to the active site of the EcR subunit of the ecdysone receptor (EcR)-ultraspiracle protein (USP) heterodimeric receptor, a series of new pyrazole amide derivatives were designed and synthesized. Their structures were confirmed by IR, ¹H NMR, ¹³C NMR and elemental analysis. Results from a preliminary bioassay revealed that two of the pyrazole derivatives exhibited promising insecticidal activity. Specifically, compounds 6e and 6i exhibited good activity against Helicoverpa armigera (cotton bollworm) at low concentration. Symptoms displayed by tebufenozide-treated H. armigera were identical with those displayed by its treated counterpart. 6i showed the same poisoning symptoms as those of tebufenozide. In addition, results from molecular docking result indicated that the binding modes of 6e and 6i at the active site of the EcR subunit of the heterodimeric receptor were similar to that of the bound tebufenozide.     

Efficient synthesis and biological evaluation of 4-arylcoumarin derivatives

Two bioactive natural 4-arylcoumarins,5,7,4’-trimethoxy-4-phenylcoumarin(1a),5,7-dimethoxy-4-phenylcoumarin(1b) and five closely related derivatives 1c-g were synthesized.In vitro evaluation with a catechol subunit for antioxidant and antimicrobial activity,these compounds using standard methods showed that compounds 1d,1f displayed promise radical scavenging activity and 1f was found to be the most active one against Bacillus dysenteriae.     

Design,synthesis and biological evaluation of isoxazole-naphthalene derivatives as anti-tubulin agents

In this study, a novel series of isoxazole-naphthalene derivatives as tubulin polymerization inhibitors were designed, synthesized and evaluated for their anti-proliferative activities against human breast cancer cell line MCF-7. Most of the synthesized compounds exhibited moderate to potent antiproliferative activity (IC₅₀ < 10.0 μM), as compared to cisplatin (15.24 ± 1.27 μM). Among them, compound 5j containing 4-ethoxy substitution at phenyl ring was found to be the most active compound with IC₅₀ value of 1.23 ± 0.16 μM. Mechanistic studies revealed that compound 5j arrested cell cycle at G2/M phase and induces apoptosis. Furthermore, in vitro tubulin polymerization assay showed that compound 5j displayed better inhibition activity on tubulin polymerization (IC₅₀ = 3.4 μM) than colchicine (IC₅₀ = 7.5 μM). Molecular docking study also revealed that compound 5j binds to the colchicine binding site of tubulin.     

Glycosylated diazeniumdiolate-based oleanolic acid derivatives: synthesis, in vitro and in vivo biological evaluation as anti-human hepatocellular carcinoma agents

A series of O(2)-glycosylated diazeniumdiolate-based derivatives of oleanolic acid (4-19) were synthesized and their anti-human hepatocellular carcinoma (HCC) activities were evaluated. Compound 6 selectively inhibited HCC, but not non-tumor liver cell proliferation. This inhibition was attributed to high levels of nitric oxide (NO) released in HCC cells. Importantly, 6 exhibited low acute toxicity (LD(50) = 173.3 mg kg(-1)) and potent inhibition of HCC tumor growth in mice (3 mg kg(-1) iv). Furthermore, 6 induced HCC cell apoptosis, which was accompanied by lower mitochondrial membrane potentials and Bcl2 expression, but with higher cytochrome C release, Bax, caspase 3 and 9 expression activities in HCC cells. Collectively, 6 may be a promising candidate drug for the intervention of HCC.