Synthesis of 11-hydroxydrim-8(9)-en-7-one and 11,12-dihydroxydrim-8(9)-en-7-one from drim-8(9)-en-7-one

A synthetic route to 11-hydroxydrim-8(9)-en-7-one and 11,12-hydroxydrim-8(9)-en-7-one, valuable key intermediates for the preparation of naturally occurring biologically active drimanic sesquiterpenoids, starting from easily available drim-8(9)-en-7-one was developed. 11-Hydroxydrim-8(9)-en-7-one was obtained by peracidic oxidation of the enol acetate of drim-8(9)-en-7-one. 11,12-Dihydroxydrim-8(9)-en-7-one was synthesized from drim-8(9)-en-7-one by two routes, namely, by a five-step procedurevia 11-hydroxydrim-8(9)-en-7-one and by bromination of drim-8(9)-en-7-one with NBS to give 11,12-dibromodrim-8(9)-en-7-one followed by its acetoxylation and deacetylation. Deceased Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 95–98, January, 2000.     

Synthesis of 11-hydroxydrim-8(9)-en-7-one and 11,12-dihydroxydrim-8(9)-en-7-one from drim-8(9)-en-7-one

A synthetic route to 11-hydroxydrim-8(9)-en-7-one and 11,12-hydroxydrim-8(9)-en-7-one, valuable key intermediates for the preparation of naturally occurring biologically active drimanic sesquiterpenoids, starting from easily available drim-8(9)-en-7-one was developed. 11-Hydroxydrim-8(9)-en-7-one was obtained by peracidic oxidation of the enol acetate of drim-8(9)-en-7-one. 11,12-Dihydroxydrim-8(9)-en-7-one was synthesized from drim-8(9)-en-7-one by two routes, namely, by a five-step procedurevia 11-hydroxydrim-8(9)-en-7-one and by bromination of drim-8(9)-en-7-one with NBS to give 11,12-dibromodrim-8(9)-en-7-one followed by its acetoxylation and deacetylation. Deceased Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 95–98, January, 2000.     

Effects of Explicit and Implicit Solvent Models on the Hydrolysis Cleavage of N-Glycosidic Bond in 8-Oxo-7,8-dihydro-2?-deoxyguanosine

8-Oxoguanine(8-oxoG), a critical mutagenic DNA lesion induced by reactive oxygen species, gives rise to a G·C→T·A transversion during replication and thereby must be repaired. The effects of explicit and implicit solvent molecules on the hydrolysis cleavage of N-Glycosidic bond in 8-oxo-7,8-dihydro-2'-deoxyguanosine(8-oxo-dG) have been systematically clarified in the present work based upon two types of computational models. Detailed potential energy surface(PES) scans and full unconstraint optimizations for all the representative points on PESs were carried out at the B3LYP/6-31+G(d) level of theory. The effect of implicit solvent was tested by single-point calculation at the SCRF/IEF-PCM model. The results illustrate that the direct hydrolysis model involving one explicit water molecule can't provide a complete depiction of the hydrolysis process of 8-oxo-dG, attributed to the insufficiency of nucleophile activation and leaving group stabilization. The expansion hydrolysis model involving four explicit water molecules, however, facilitates discrete proton transfer and therefore produces smooth reaction surfaces for both the dissociative(SN1) and concerted(SN2) pathways. The presence of the implicit solvent substantially lowers all activation energies and the SN1 process is more favorable than the SN2 process. The data and insights present here agree well with the experimental results and have given out a baseline for the enzymatic deglycosylation reaction of 8-oxo-dG.     

7-硝基-8-羟基喹啉的合成

以8-羟基喹啉为原料,经硝化和脱磺酸基保护两步反应合成了7-硝基-8-羟基喹啉,总收率69％,纯度高于99％.其结构经1H NMR,13C NMR和HR-MS确证.     

Chemoselective synthesis of 5-amino-7-bromoquinolin-8-yl sulfonate derivatives and their antimicrobial evaluation

Abstract

A series of new 5-amino-7-bromoquinolin-8-ol sulfonate derivatives 5(a–j) were synthesized from 8-hydroxyquinoline through multi-step process with high yields using mild, efficient and conventional methods. Chemoselectivity was observed during the transformation of 5-amino-7-bromoquinolin-8-ol to 5-amino-7-bromoquinolin-8-ol sulfonate with various sulfonylchlorides exclusively to afford sulfonate derivatives. Also, the products were investigated for their in vitro antimicrobial activities and compared with the standard drugs. Among all the synthesized compounds 5-amino-7-bromoquinolin-8-yl biphenyl-4-sulfonate (5b) and 5-amino-7-bromoquinolin-8-yl 2-hydroxy-5-nitrobenzenesulfonate (5g) have showed potent antibacterial activity, whereas 5-amino-7-bromoquinolin-8-yl biphenyl-4-sulfonate (5b) and 5-amino-7-bromoquinolin-8-yl 2-hydroxy-5-nitrobenzenesulfonate (5g) possessed potent antifungal activities among all the tested pathogens.     

Technology of Preparing 8-Hydroxy-5-nitroquinoline

An efficient, two stage method is proposed for the preparation of 8-hydroxy-5-nitroquinoline based on the nitrosation of 8-hydroxyquinoline and subsequent oxidation of the nitroso derivative using nitric acid. The conditions for the nitrosation and oxidation of the 8-hydroxyquinoline (concentration of nitric acid, temperature, and reaction time) were optimized. A method for purifying the target compound is presented. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1204–1207, August, 2005.     

Photooxidative dehydrogenation of Δ8-drimen-and Δ8-11-homodrimen-7-ones into α,α ′-dienones

An efficient two-step procedure for photooxidative dehydrogenation of drimane and 11-homodrimane compounds containing an 8-en-7-one structural unit into α,α′-dienones was elaborated. The method is based on the transformation of ketones into the respective enol acetates followed by photosensitized oxygenation. Methyl 7-oxo-11-homodrima-5,8-dien-12-oate, 5,6-dehydro-7-ketoisodrimenine, 11-acetoxydrima-5,8-dien-7-one and 11,12-diacetoxydrima-5,8-dien-7-one were prepared in high yields starting from methyl 7-oxo-11-homodrim-8-en-12-oate, 7-oxoisodrimenine, 11-hydroxydrim-8-en-7-one and 11,12-diacetoxydrim-8-en-7-one, respectively. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 678–682, April, 2006.     

A Convenient Modified Short Route for the Preparation of [32]ane‐N8 Hydrochloride

A convenient modified short‐cut route for the preparation of a 32‐membered octaazamacrocyclic molecule, 1,5,9,13,17,21,25,29‐octaazacyclodotriacontane hydrochloride, [32]ane‐N₈·8HCl has been described. The proper tetramine has been contemplated to go this new pathway which propagates [32]‐N8·8HCl more effectively.     

Modified Coumarins. II. Mannich Reaction of Substituted 4-Phenylcoumarins

Aminomethylation of 5-hydroxy- and 7-hydroxy-4-phenylcoumarins by substituted 1,1-diaminomethanes is studied. Mannich condensation of amino acids and their esters with 7-hydroxy-4-phenylcoumarin gives a series of 8-aminoacylmethylcoumarins and 4-phenyl-9,10-dihydro-2H,8H-chromeno[8,7-e][1,3]oxazin-2-ones     

Solvothermal Route to Prepare the Metastable Phase 3c-Fe7S8 with Hexagonal Platelet Morphology

The metastable phase 3c-Fe7S8 with the hexagonal platelct morphology has been prepared by using solvothermal route.The product was characterized by mcans of X-ray powder diffraction(XRD) and transmission electron microscopy (TEM) and X-ray photoelectron speetra (XPS).The experiment results show that the as-prepared Fe7S8 is a metastable phase with the hexagonal platelet morphology.     

Synthesis of 5,6-dehydro-7-oxoisodrimenin from drim-8-en-7-one

The natural drimane sesquiterpenoid lactone 5,6-dehydro-7-oxoisodrimenin was synthesized from drim-8-en-7-one as well as from 7-oxoisodrimenin.     

A Novel Sesquiterpenoid from Glechoma longituba

Glechoma longituba (NaKai) Kupr. as a folk medicine, widely distribute in China. The whole plant has been used for treatment of urosealith and urinary tract infection1. It was previously reported1, 2 that some compounds, such as glechomafuran, ursolic aci…     

8-羟基喹啉-7-醛缩氨基硫脲衍生物的微波合成及抗肿瘤活性研究

以8-羟基喹啉-7-醛和一系列芳基及烷基取代氨基硫脲为原料,合成了15种8-羟基喹啉缩氨基硫脲类化合物。缩合反应在绿色溶剂水中进行,微波辐射下15-30 min内反应完全,操作简单,收率高。化合物结构经1H NMR、IR和高分辨质谱确证。部分化合物经抗肿瘤活性初步测试结果表明,多数化合物对细胞周期分裂蛋白25B(CDC25B)抑制率达到90%以上,具有潜在的抗肿瘤活性。     

Synthesis of 8-halogenated-7-deaza-2′-deoxyguanosine as an 8-oxo-2′-deoxyguanosine analogue and evaluation of its base pairing properties

8-Halogenated-7-deaza-2′-deoxyguanosines (8-halo-7-deaza-dG) were designed to structurally mimic 8-oxo-2′-deoxyguanosine (8-oxo-dG), which is representative of an oxidized nucleoside. It has been shown by NMR that the conformation around the N-glycosidic bond of (8-halo-7-deaza-dG) is preferably syn, similar to 8-oxo-dG. The base pairing properties of 8-halo-7-deaza-dG were studied by measuring the thermal denaturation temperature of the duplexes, showing that their base pair with dC is destabilized compared with natural dG. These results also support their preference for syn conformation. Unlike 8-oxo-dG, 8-halo-7-deaza-dG did not form a stable base pair with dA, most likely due to the lack of N7-H hydrogen bonding with dA. In conclusion, the newly-designed 8-halo-7-deaza-dG analogs resemble 8-oxo-dG in its shape and preference for syn conformation, but they do not form Hoogsteen base pair with the opposing dA.     

Antiproliferative effect of isolated isoquinoline alkaloid from Mucuna pruriens seeds in hepatic carcinoma cells

The present study was undertaken to investigate the antiproliferative action of isolated M1 (6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid) from Mucuna pruriens seeds using human hepatic carcinoma cell line (Huh-7 cells). Initially, docking studies was performed to find out the binding affinities of M1 to caspase-3 and 8 enzymes. Later, cytotoxic action of M1 was measured by cell growth inhibition (MTT), followed by caspase-3 and 8 enzymes assay colorimetrically. Our results collectively suggested that M1 had strong binding affinity to caspase-8 in molecular modelling. M1 possessed antiproliferative activity on Huh-7 cells (EC₅₀ = 13.97 μM) and also inhibited the action of caspase-8 enzyme, signified process of apoptosis. M1 was active against Huh-7 cells that may be useful for future hepatic cancer treatment.     

Facile Synthesis of 9-Acetyl/Formyl/Cyano-Substituted Pyrano[2,3-f]flavones and Chromones Using the Baylis–Hillman Reaction

Condensation of 8-formyl-7-hydroxyflavones (2a–f) and 8-formyl-7-hydroxy-2-(2′-furyl)-3-methylchromone (2g) with methyl vinyl ketone (3), acrolein (4), and acrylonitrile (5) in the presence of diazabicyclo[2.2.2]octane (DABCO) under an N₂ atmosphere at room temperature using Baylis–Hillman reaction conditions afforded 9-acetyl/formyl/cyano-substituted pyrano2,3-f]flavones (6a–f, 7a–f, 8a–f) and chromones (6g, 7g, 8g).     

Chelate von Chinolin-8-ol-Derivaten. XII. Die Kristall- und Molekülstruktur von Bis(7-isopropylchinolin-8-olato)nickel(II)

Chelates of 8-Quinolinol Derivatives. XII. Crystal and Molecular Structure of Bis(7-isopropyl-8-quinolinato)nickel(II) The crystal and molecular structure of bis(7-isopropyl-8-quinolinato)nickel(II) was determined by X-ray diffraction. The structure is monoclinic with the space group P2₁/n (Z = 2, 1403 observed independent reflections, R = 0.049. Lattice dimensions at 20°C: a = 1328.3(5) pm, b = 632.8(2) pm, c = 1330.0(5) pm, β = 112.99(3)°). The coordination of the nickel atom is planar with the quinoline rings in trans position.     

Fabrication of ZiF-8 metal organic framework (MOFs)-based CuO-ZnO photocatalyst with enhanced solar-light-driven property for degradation of organic dyes

In this research, novel CuO-ZnO/ZiF-8 metal–organic frameworks (MOFs) photocatalyst with different mass percentages of ZiF-8 were prepared for water purification applications under visible light. The precipitation method was used to synthesize CuO-ZnO/ZiF-8 photocatalysts. Some techniques, including XRD, FESEM, EDX, BET-BJH, FTIR, DRS, and pH_pzc, were performed to determine the structural, chemical, and optical properties of the prepared samples. DRS analysis represented that CuO-ZnO/ZiF-8(20) had narrower band gap energy compared to CuO-ZnO and ZiF-8. Also, BET-BJH analysis results showed that CuO-ZnO had a low surface area that impeded the absorption of pollutant molecules. In contrast, the CuO-ZnO/ZiF-8(20) sample, due to the presence of ZiF-8, had a high specific surface area which enabled higher pollutant adsorption on the photocatalyst surface.Moreover, the synthesized samples were evaluated for the solar-light-driven removal of different organic dyes, such as Acid Orange 7, Methylene blue, and Malachite green. The tremendously enhanced photocatalytic activity under the simulated solar light with 98.1% removal of AO7 was observed over CuO-ZnO/ZiF-8(20) sample. Then, the effect of initial solution pH as an essential factor on photocatalytic activity was investigated. Finally, the reaction mechanism of AO7 degradation over CuO-ZnO/ZiF-8(20) was proposed.     

Oligonucleotides containing 7-propynyl-7-deazaguanine: synthesis and base pair stability

Oligonucleotides incorporating the propynyl derivative of 7-deaza-2′-deoxyguanosine (1) were synthesized by solid-phase oligonucleotide synthesis. As building blocks the phosphoramidites 7a,b were prepared. The incorporation of 1 into oligonucleotides exerts a positive effect on the DNA duplex stability. The duplex stabilization by 1 was higher than that of 7-iodo-7-deaza-2′-deoxyguanosine (2b). The stabilizing effect of the 7-propynyl group introduced in the 7-deazapurines is similar to that reported for 8-aza-7-deazapurines. From CD spectra it was deduced that the B-DNA structure is not significantly altered by compound 1.     

Three antibacterial naphthoquinone analogues from cultured mycobiont of lichen Astrothelium sp.

<正>A new naphthoquinone compound named 7-hydroxyl-8-methoxyltrypethelone 3 together with two known compounds trypethelone 1 and trypethelone methyl ether 2 was isolated from cultured mycobiont of Astrothelium sp.The structures were elucidated by 1D and 2D NMR spectroscopic analysis as well as comparison with those reported in literatures.Compound 1 displayed significant antibacterial activity against Bacillus subtilis(ATCC 6633),and showed modest antibacterial activity against Staphylococcus aureus col(MRSA)(CGMCC 1.2465),while compounds 2 and 3 showed modest antibacterial activity against Enterococcus faecalis 850E(CGMCC 1.2135) and S.aureus col(MRSA)(CGMCC 1.2465).