Eight novel oxdiazolo[3,4-d]pyrimidine nucleoside derivatives (I-VIII) were synthesized to investigate their anti-tumor effects and possible mechanisms. Four human cancer cell lines including Hela, ECA109, HepG2 and A459 cells were used. Compounds VI and VIII showed significant inhibition on cancer cell proliferation by MTT assay and IC50 values were around 30-70 micromol l(-1). Both compounds could release nitric oxide (NO), led to a significant intracellular free Ca2+ overloading and resulted in mitochondrial dysfunction, showing a decrease in mitochondrial membrane potential in HepG2 cells in a dose-dependent manner. Furthermore, compound VIII induced obvious DNA damage on HepG2 cells. These data indicate that compounds VI and VIII are two active antitumor compounds, and both DNA damage and mitochondrial dysfunction are involved in the mechanisms underlying oxadiazolo[3,4-d]pyrimidine nucleoside derivative-induced cancer cell death, which might also be related to the released NO.
Abstract A three‐step, one‐pot tandem reaction including radical nucleophilic alkylation/cyclization/aromatization was developed using 0.3 equivalents of silver(I) acetate (AgOAc) as the catalyst and 2 equivalents of ammonium persulfate [(NH 4 ) 2 S 2 O 8 ] as the oxidant. This strategy is highly efficient for the assembly of pentacyclic complex carbazoles from aryl‐fused bromobenzoquinones and indol‐3‐ylpropanoic acid acids in 52–72% overall yields (three steps). This new approach provides a significant improvement over the previously reported methods and would greatly facilitate analog library construction of pentacyclic complex carbazoles and benefit further biological evaluation of these compounds.
Background: Halofuginone hydrobromide (1) is recognized as an effective drug against several species of Eimeria (E.) in poultry. In this paper, we describe a convenient and low cost preparation method for the compound, as well as primary validation of its activity. Methods: First, 7-bromo-6-chloroquinazolin-4(3H)-one (2) was prepared from m-chlorotoluene by a conventional process, and then chloroacetone was creatively introduced in two steps. Finally, halofuginone hydrobromide (1) was obtained from 7-bromo-6-chloro-3-(3-cholroacetonyl) quinazolin-4(3H)-one (4) by a four-step reaction sequence including condensation, cyclization, deprotection and isomerization. The structures of the relative intermediates and target compound were characterized by melting point, IR, MS and ¹H-NMR. Besides, the protective effect of compound 1-supplemented chicken diet at doses of 6, 3 and 1.5 mg per 1 kg were evaluated on chickens infected with E. tenella, by reduction in mortality, weight loss, fecal oocyst excretion and gut pathology, respectively. Results: Halofuginone hydrobromide (1) was prepared successfully by and improved and innovative method based on traditional research. Moreover, the synthesized halofuginone hydrobromide significantly exhibited an anti-coccidial property. Conclusions: The fruitful work described in this Communication has resulted in halofuginone hydrobromide, which has a good pharmaceutical development prospects, becoming more available for large-scale production.
The cyclization reactions of arylamines with 2-deoxy-D-ribose or glycals were reinvestigated in the current report. In the montmorillonite KSF- or InCl(3)-initiated reactions of 2-deoxy-D-ribose with arylamines, a pair of diastereomeric tetrahydro-2H-pyran-fused tetrahydroquinolines was obtained in a nearly 1:1 ratio where the structure of one diastereomer was incorrectly assigned in the literature. Meanwhile, the diastereoselectivity in InBr(3)-catalyzed cyclization of glycals with arylamines was also incorrectly reported previously. It was found that high diastereomeric selectivity was achieved only when a C5-substituted glycal was used; otherwise, a pair of diastereomers was obtained in moderate yield with 1:1 diastereomeric ratio. Furthermore, tetrahydrofuran-fused tetrahydroquinolines 5b and 5b' were also prepared successfully by using TBDPS-protected ribose as the glycal precursor and montmorillonite KSF as the activator.
The strategies,methods,paths,characters,starting materials and nitrating systems of synthesizing 2,4,6-trinitro-2,4,6-triazacyclohexanone(Keto-RDX) were summarized,analysized and reviewed with 22 references.Considering that direct method using urotropine and urea as starting materials has the advantages of less steps,lower cost and higher yield and the disadvantages of difficult separation and purification from a mixtures of Keto-RDX and RDX,while the multistep method of synthesizing Keto-RDX via 1,3,5-triazine intermediates has the disadvantages of more reaction steps and higher cost and the advantages of easier separation and purification.
A new ruthenium catalytic system was developed for the construction of a C(sp2)–Se bond with the assistance of directing groups. This protocol features mild reaction conditions, wider substrate scope, and convenient late-stage selenylation of bioactive molecules.
Matrix metalloproteinase-9 (MMP-9) has been considered as an attractive target involving cancer therapy. In this study, the 3D QSAR pharmacophore model of MMP-9 inhibitors is built, and its reliability is subsequently validated based on different methods. The built pharmacophore model consists of the four chemical features, including two hydrogen bond acceptors (HBA), one hydrophobic (HY), and one ring aromatic (RA). Among them, both HY and RA are found to be especially important features because they involve the interactions of inhibitors with the S1′ pocket of MMP-9, which determines the selectivity of MMP-9 inhibitors. By combining pharmacophore model with molecular docking, the virtual screening is carried out to identify the selective MMP-9 inhibitors from natural products. The four potential selective MMP-9 inhibitors of natural products are found. One of them was used to carry out the bioassay experiment inhibiting MMP-9, and the estimated IC50 value of only 26.94 µM clearly shows its strongly inhibitory activity; besides, both the hybrid quantum mechanics/molecular mechanics (QM/MM) calculation and the molecular dynamics simulation are performed to examine the reliability regarding the binding mode of this inhibitor with MMP-9 active sites predicted by molecular docking. All the screened four natural products are found to well bind with the MMP-9 active sites by different kinds of interactions. Finally, the ADMET properties of screened four natural products are assessed. These screened MMP-9 inhibitors of natural products could be used as the lead compounds to perform structural modifications and optimizations in the future work.Communicated by Ramaswamy H. Sarma
In this paper, the various antineoplastic mechanisms of Vitamin K3 were observed. The structureactivity relationship of VK3 derivates was explained in detail. A variety of small compounds derived from the prodrug (1, 4-naphthoquinone) of VK3 was also described. In addition, the anti-tumor activity and outlooks of these compounds were particularly discussed.
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