Di-Isatropolone C, a Spontaneous Isatropolone C Dimer Derivative with Autophagy Activity.

Isatropolone C from Streptomyces sp. CPCC 204095 features a fused cyclopentadienone-tropolone-oxacyclohexadiene tricyclic moiety in its structure. Herein, we report an isatropolone C dimer derivative, di-isatropolone C, formed spontaneously from isatropolone C in methanol. Notably, the structure of di-isatropolone C resolved by NMR reveals a newly formed cyclopentane ring to associate the two isatropolone C monomers. The configurations of four chiral carbons, including a ketal one, in the cyclopentane ring are assigned using quantum NMR calculations and DP4+ probability. The plausible molecular mechanism for di-isatropolone C formation is proposed, in which complex dehydrogenative C-C bond coupling may have happened to connect the two isatropolone C monomers. Like isatropolone C, di-isatropolone C shows the biological activity of inducing autophagy in HepG2 cells.

Design, synthesis and antiproliferative evaluation of new tricyclic fused thiazolopyrimidines targeting topoisomerase II: Molecular docking and apoptosis inducing activity.

A novel series of thiazolopyrimidines and fused thiazolopyrimidines was designed and synthesized as topoisomerase II alpha inhibitors. All synthesized compounds were screened by the National Cancer Institute (NCI), Bethesda, USA for anticancer activity against 60 human cancer cell lines representing the following cancer types: leukemia, non-small cell lung, colon, CNS, melanoma, ovarian, renal, prostate, and breast cancers. Compound 3a was found to be the most potent inhibitor on renal cell line (A-498) causing 83.03% inhibition (IC50 = 1.89 µM). DNA-flow cytometric analysis showed that compound 3a induce cell cycle arrest at G2/M phase leading to cell proliferation inhibition and apoptosis. Moreover, fused thiazolopyrimidines 3a showed potent topoisomerase II inhibitory activity (IC50 = 3.19 µM) when compared with reference compound doxorubicin (IC50 = 2.67 µM). Docking study of all the synthesized compounds showed that compound 3a interacts in a similar pattern to etoposide and stabilizing the topoisomerase cleavage complex (Top2-cc) that accounts for its high potency.

Temperature-responsive mixed-mode column containing temperature-responsive polymer-modified beads and anionic polymer-modified beads.

We developed temperature-responsive mixed-mode columns packed with poly(N-isopropylacrylamide) (PNIPAAm)-modified beads and poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS)-modified beads in various ratios. The PNIPAAm-modified silica beads and PAMPS-modified silica beads were prepared by surface-initiated atom transfer radical polymerization of N-isopropylacrylamide and 2-acrylamido-2-methylpropane sulfonic acid, respectively. We confirmed polymer modification of the silica beads by CHN elemental analysis, FTIR, zeta-potential measurements, and SEM. To determine the column separation efficiency, we examined the elution behaviors of cold medicine active ingredients and monoamines from each column. Analyte separation occurred on columns with PNIPAAm to PAMPS ratios of 1:20 and 1:10, whereas a column containing only PNIPAAm-modified beads did not retain the analytes. The analytes were retained on the columns through hydrophobic and electrostatic interactions with PNIPAAm and PAMPS, respectively. The separation performance improved with increasing column temperature because of dehydration of PNIPAAm and enhancement of hydrophobic interactions at elevated temperatures. The mixed-mode columns will be useful for separating basic bioactive compounds because the retention of analytes can be modulated by changing the column temperature and the composition.

Antimicrobial Activity of Substituted Benzopentathiepin-6-amines.

A number of substituted benzopentathiepin-6-amines and their analogues without a polysulfur ring were synthesized and evaluated in vitro for antimicrobial activity against a panel of reference bacterial and fungal strains. Trifluoroacetamide 14 demonstrated high antibacterial activity against Staphylococcus aureus (MRSA strain) with a MIC of 4 µg/mL, which was four-fold higher than the activity of a reference drug amoxicillin. This compound was also most active against the Candida albicans fungus (MIC of 1 µg ml-1), whereas amide 17 containing a morpholine substituent was most active against the Cryptococcus neoformans fungus (MIC of 2 µg ml-1). These compounds have no hemolytic activity and are low cytotoxic. Replacement of the pentathiepine ring with 1,3-dithiolan-2-one or 1,3-dithiolane moieties leads to loss of antimicrobial activity. Based on the QSAR analysis and molecular docking data, bacterial DNA ligase might be one of the targets for the antibacterial activity of substituted benzopentathiepin-6-amines against S. aureus.

The Human Fecal Microbiota Metabolizes Foodborne Heterocyclic Aromatic Amines by Reuterin Conjugation and Further Transformations.

SCOPE: Heterocyclic aromatic amines (HAAs) are process-induced food contaminants with high mutagenic and/or carcinogenic potential. Although the human gut microbiota is known to affect the metabolism of dietary constituents, its impact on HAA metabolism and toxicity has been little studied. Here, the glycerol-dependent metabolism of seven foodborne HAAs (AαC, Trp-P-1, harman, norharman, PhIP, MeIQx, and MeIQ) by the human fecal microbiota is investigated. METHODS AND RESULTS: As analyzed by HPLC-DAD/FLD, the extent of conversion is strongly dependent on glycerol supplementation and HAA structure. AαC (60-100%) and the 2-aminoimidazoazarenes (up to 58%) are especially prone to microbial conversion. Based on high-resolution MS and/or NMR spectroscopy data, 70 fecal metabolites are identified in total, mainly formed by chemical reactions with one or two molecules of microbially derived reuterin. Moreover, it has been demonstrated that the human fecal microbiota can further transform reuterin adducts by reduction and/or hydroxylation reactions. Upon isolation, some reuterin-induced HAA metabolites appear to be partially unstable, complicating structural identification. CONCLUSION: The formation of microbial metabolites needs to be incorporated into risk assessment considerations for HAAs in human health. In this study, several HAA metabolites, mainly reuterin-dependent, are identified in vitro, providing the basis for future human studies investigating microbial HAA metabolism.

The influence of some promising fused azaisocytosine-containing congeners on zebrafish (Danio rerio) embryos/larvae and their antihaemolytic, antitumour and antiviral activities.

The present study was aimed at broadening the profile of toxicity and biological activity of promising fused azaisocytosine-containing congeners (I-VI) possessing medical applicability and important pharmacokinetic properties. For this purpose, the in vivo zebrafish test was applied for evaluating embryotoxic effects of test compounds, whereas the ex vivo model of oxidatively-stressed rat erythrocytes was developed for assessing their antihaemolytic activities. Additionally, the MTT-based assays suitable for assessing cytotoxic and antiviral activities of I-VI were employed. The influence of compounds I-VI on zebrafish embryos/larvae was carefully investigated in relation to lack or presence of various substituents at the phenyl moiety. The least embryotoxic proved to be the parent compound (I) and its para-methyl (II) and ortho-chloro (III) derivatives. Simultaneously, they revealed the minimum embryotoxic concentrations higher than that of aciclovir, what makes them safer than this pharmaceutic. Moreover, most of test compounds showed protective effects (better or comparable to that of ascorbic acid) on oxidatively-stressed erythrocytes. All the investigated compounds were effective at inhibiting the growth of human solid tumours of pharynx (FaDu) and tongue (SCC-25). The majority of molecules showed good selectivity indices. The most selective proved to be II showing in normal Vero cells over a 5-fold and an almost 3-fold decreased cytotoxicity relative to that in tumour SCC-25 and FaDu cells, respectively. Additionally, a 3,4-dichloro derivative (VI) was shown to possess concentration-dependent inhibitory effects on the replication of Herpes simplex virus type 1 and simultaneously at active concentrations was found to be nontoxic for normal Vero cells.

A Greener and Efficient Method for Nucleophilic Aromatic Substitution of Nitrogen-Containing Fused Heterocycles.

A simple and efficient methodology for the nucleophilic aromatic substitution of nitrogen-containing fused heterocycles with interesting biological activities has been developed in an environmentally sound manner using polyethylene glycol (PEG-400) as the solvent, leading to the expected compounds in excellent yields in only five minutes.

Synthetic Studies on Heteropolycyclic Natural Products: Development of Divergent Strategy.

The divergent total syntheses of three types of heteropolycyclic natural products, namely gelsedine-type alkaloids, amathaspiramide alkaloids, and erythrina alkaloids, are outlined. A strategy involving a late-stage pluripotent common synthetic intermediate prepared via original and innovative transformations was employed. A brief description of the philosophy and criteria for choosing the synthetic targets and common synthetic precursors, as well as details regarding the development of the overall synthetic schemes from a common intermediate are discussed.

Multinuclear Phthalocyanine-Fused Molecular Nanoarrays: Synthesis, Spectroscopy, and Semiconducting Property.

The post-cyclization strategy rather than the conventional ante-cyclotetramerization method was employed for the synthesis of multinuclear phthalocyanine-fused molecular nanoarrays. Reaction of 2,3,9,10,16,17-hexakis(2,6-dimethylphenoxy)-23,24-diaminophthalocyaninato zinc(II) with 2,7-di-tert-butylpyrene-4,5-dione, 2,7-di-tert-butylpyrene-4,5,9,10-tetraone, and hexaketocyclohexane in refluxing acetic acid afforded the corresponding mono-, bi-, and trinuclear phthalocyanine-fused zinc complexes (Pz-pyrene){Zn[Pc(OC8 H9 )6 ]} (1), (Pz2 -pyrene){Zn[Pc(OC8 H9 )6 ]}2 (2), {(HAT){Zn[Pc(OC8 H9 )6 ]}3 } (3) in 46, 13, and 25 % yield, respectively, which extend the scope of multinuclear phthalocyanine-fused nanoarrays with different molecular skeletons. The self-assembly behavior of trinuclear phthalocyanine 3 in THF/CH3 CN was investigated by electronic absorption spectroscopy and SEM, and the fabricated nanorods showed interesting semiconducting properties, which suggest good application potential of these multinuclear phthalocyanine-fused molecular nanoarrays.

A One-Pot Multicomponent 1,3-Dipolar Cycloaddition Strategy: Combinatorial Synthesis of Dihydrothiophenone-Engrafted Dispiro Hybrid Heterocycles.

The combinatorial syntheses of a library of novel dihydrothiophenone-engrafted dispiro oxindole/indenoquinoxaline-pyrrolidine/pyrrolothiazole/indolizine hybrid heterocycles have been realized through a chemo-, regio-, and stereoselective multicomponent 1,3-dipolar cycloaddition strategy.

A Tandem Enzymatic sp2 -C-Methylation Process: Coupling in Situ S-Adenosyl-l-Methionine Formation with Methyl Transfer.

A one-pot, two-step biocatalytic platform for the regiospecfic C-methylation and C-ethylation of aromatic substrates is described. The tandem process utilises SalL (Salinospora tropica) for in situ synthesis of S-adenosyl-l-methionine (SAM), followed by alkylation of aromatic substrates by the C-methyltransferase NovO (Streptomyces spheroides). The application of this methodology is demonstrated for the regiospecific labelling of aromatic substrates by the transfer of methyl, ethyl and isotopically labelled 13 CH3,13 CD3 and CD3 groups from their corresponding SAM analogues formed in situ.

Design of New Benzo[h]chromene Derivatives: Antitumor Activities and Structure-Activity Relationships of the 2,3-Positions and Fused Rings at the 2,3-Positions.

A series of novel 4H-benzo[h]chromenes 4, 6-11, 13, 14; 7H-benzo[h]chromeno[2,3-d]pyrimidines 15-18, 20, and 14H-benzo[h]chromeno[3,2-e][1,2,4]triazolo[1,5-c]pyrimidine derivatives 19a-e, 24 was prepared. The structures of the synthesized compounds were characterized on the basis of their spectral data. Some of the target compounds were examined for their antiproliferative activity against three cell lines; breast carcinoma (MCF-7), human colon carcinoma (HCT-116) and hepatocellular carcinoma (HepG-2). The cytotoxic behavior has been tested using MTT assay and the inhibitory activity was referenced to three standard anticancer drugs: vinblastine, colchicine and doxorubicin. The bioassays demonstrated that some of the new compounds exerted remarkable inhibitory effects as compared to the standard drugs on the growth of the three tested human tumor cell lines. The structure-activity relationships (SAR) study highlights that the antitumor activity of the target compounds was significantly affected by the lipophilicity of the substituent at 2- or 3- and fused rings at the 2,3-positions.

Three-Component, Diastereoselective Prins-Ritter Reaction for cis-Fused 4-Amidotetrahydropyrans toward a Precursor for Possible Neuronal Receptor Ligands.

Here, we report an unprecedented, highly diastereoselective Prins-Ritter reaction of aldehydes, homoallylic alcohols, and nitriles in a three-component coupling reaction for the synthesis of tetra-cis-substituted 4-amidotetrahydropyrans. In this study, the reaction was not only applied for carbohydrate-based heterobicycles but also for more complex heterotricycles, showing acceptable levels of conversion yield (42-97% BRSM) and exclusive diastereoselectivity. Furthermore, the latter heterotricycles were converted to nine analogues of our neuronal receptor ligands IKM-159 and MC-27. An in vivo assay by intracerebroventricular injection in mice suggested that the substituent at C9 of the novel analogues interferes with the molecular interactions with the AMPA receptor, which was originally observed in the complex of IKM-159 and the GluA2 ligand binding domain. Our research has thus shown the power of a multicomponent coupling reaction for the preparation of a structurally diverse compound collection to study structure-activity relationships of biologically active small molecules.

[Synthetic Studies of Bioactive Heterocyclic Natural Products and Fused Heterocyclic Compounds Based on the Thermal Electrocyclic or Azaelectocyclic Reaction of 6π-Electron or Aza-6π-electron Systems].

Since 1979, synthetic studies of bioactive heterocyclic natural products and condensed heteroaromatic compounds based on the thermal electrocyclic reaction of 6π-electron or aza-6π-electron systems incorporating the double bond of the principal aromatic or heteroaromatic ring have been conducted by our research group. In this review, five types of electrocyclic and azaelectrocyclic reaction are described: 1) the synthesis of the carbazole alkaloids hyellazole and 6-chlorohyellazole through the electrocyclic reaction of 2,3-bisalkenylindoles; 2) synthetic studies of the pyridocarbazole alkaloids ellipticine and olivacine through the electrocyclic reactions of the indole-2,3- and pyridine-3,4-quinodimethane intermediates; 3) synthetic studies of polysubstituted carbazole alkaloids through the allene-mediated electrocyclic reactions involving the indole 2,3-bond; 4) synthetic studies of fused pyridine rings through the azaelectrocyclic reaction of the 1-aza-6π-electron system using the oxime or oxime ether; and 5) synthetic studies of fused pyridine rings through the azaelectrocyclic reaction of the 2-aza-6π-electron system using a carbodiimide or isocyanate.

Current Progresses and Trends in the Development of Progesterone Receptor Modulators.

The progesterone receptor (PR) is a ligand-activated steroid receptor in the nuclear receptor (NR) superfamily of transcription factor. Besides gynecological and obstetrical indications, the involvement/mechanism of PR in many other diseases, such as oncology, neurology, immunology, etc. has been revealed and studied in recent decades. Therapeutic agents that selectively activate or inhibit PR have been developed. PR agonists have generally been used in oral contraception and postmenopausal hormone replacement therapy (HRT), typically in combination with estrogens. PR antagonists and selective PR modulators (SPRMs) can be useful therapies for hormone dependent breast and prostate cancers, nonmalignant chronic conditions such as fibroids, and endometriosis. This review provides an overview and detailed discussions about the recent development of chemical structures of the PR ligands, their structural characteristics (particularly those contributing to their activity and selectivity), in vitro/in vivo studies and clinical trial outcomes, and the synthetic methodologies.