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1.
The deoxygenation reaction of heptanones, cycloheptanone, cycloheptatrienone or substituted cycloheptatrienone with dihalo-carbene results in carbon monoxide and corresponding halides. The yield of CO produced by 2 , 4 , 6-triphenylcycloheptatrienone is 2.6-3.5 times as high as that produced by the saturated heptanones. The structures, energies, charge distributions, bond orders, and other relative parameters of the dihalocarbonyl glides were calculated by using the SCF-MNDO method. The obtained data reveal that the ylides from cycloheptatrienone have aromatic structure and are different from those produced from saturated cycloheptanone. The reactivities of the dihalocarbonyl ylides are discussed. It is proposed that this aromatic structure should be responsible for the high yield of CO from the reaction of cycloheptatrienone with dihalocarbene. 相似文献
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The regioselective synthesis of N-alkyl pyridones can be facilitated by alkylation of 2-methoxypyridines with activated halides. The syntheses are facile and high yielding with no traces of 2-alkoxypyridines. 相似文献
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The thermal rearrangement of 9-allyloxy-10-phenyl-anthracene (and related ethers) to 10-allyl-10-phenylanthrone (and related anthrones) is described. Evidence supporting a radical rearrangement pathway is presented. 相似文献
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O-Cyanomethyl ethers of carbohydrates are shown to be versatile intermediates for the preparation of sugar amines, carboxylic acids, amides, and amidine salts. This methodology for the functionalization of carbohydrates can thus provide a new array of analogs for the study of carbohydrate binding proteins. In addition, the resulting O-aminoethyl and O-carboxymethyl carbohydrates can be coupled to amino acids under standard conditions used in solid-phase peptide synthesis, providing a method for the construction of glycopeptides in which the carbohydrate moiety can be linked through any of its hydroxyl groups to the C- or the N-terminus of a given peptide. 相似文献
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D. V. Nasyrov A. A. Bobyleva A. A. Abramov S. N. Anfilogova M. A. Vasil'kov A. V. Anisimov 《Chemistry of Heterocyclic Compounds》2002,38(4):456-465
12- and 15-Membered thia- and oxathiacrown ethers and podands containing cycloheptane and cyclooctane fragments have been synthesized. The properties of the synthesized compounds as extractants for Ra2+ and Pd2+ ions have been studied. 相似文献
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We are grateful to the donors of the Petroleum Research Fund, administered by the American Chemical Society, to the National Science Foundation and to the Research Board of the University of Illinois for support of this research, to Dr. B. Willhalm for useful comments and to the Department of Organic Chemistry, University of Geneva, for its hospitality (1971/72). 相似文献
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The reduction of aryl aldehydes and ketones in neutral medium, to the corresponding hydrocarbons via carbon-nitrogen bond cleavage of the intermediate N-(arylmethyl)anilines with low-valent titanium reagents is described. It provides a mild, convenient and selective pathway for deoxygenation of carbonyls without the production of any side product. 相似文献
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Charles W. Jefford Maria G. H. Vicente Yvan Jacquier France Favarger Jiri Mareda Patricia Millasson-Schmidt Gerhard Brunner Ulrich Burger 《Helvetica chimica acta》1996,79(5):1475-1487
The treatment of artemisinin ( 1 ) and β-artemether ( 6 ) with Zn dissolving in AcOH for a few hours results in mono-deoxygenation giving deoxyartemisinin ( 5 ) and deoxy-β-artemether ( 7 ), respectively, as the sole product. In contrast, submission of 1 to FeCl2 · 4 H2O in MeCN at room temperature for 15 min causes only isomerization, (3aS,4R,6aS,7R,10S,10aR)-octahydro-4,7-dimethyl-8-oxo-2H-10H-furo[3,2-i] benzopyran-10-yl acetate ( 8 ) and (3R)-3-hydroxydeoxyartemisinin ( 9 ) being produced in 78 and 17% yield, respectively. The action of FeCl2 · 4 H2O in MeCN on 6 is similar. Under the same conditions, 6 gives products analogous to 8 and 9 accompanied by an epimeric mixture of 2-[4-methyl-2-oxo-3-(3-oxobutyl)cyclohexyl]propanaldehyde in yields of 32, 23, and 16%, respectively. No epoxide is formed on repeating the last two experiments in the presence of cyclohexene. The deoxygenation of 1 and 6 by Zn is rationalized in terms of its oxophilic nature. The catalyzed isomerization of 1 and 6 by Fe2+ is attributed to the redox properties of the Fe2+/Fe3+ system. 相似文献
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建立了液液萃取耦合气相色谱/质谱联用(GC/MS/MS)分析斑马鱼卵中10种多溴联苯醚(PBDEs),12种甲氧基化多溴联苯醚(MeO-PBDEs)和9种羟基化多溴联苯醚(HO-PBDEs)不同极性组分的同步分析方法。优化了前处理步骤和色谱质谱条件,采用液液萃取法提取目标化合物,不必分离即可实现目标化合物的衍生化,使样品前处理时间大大缩短,实现了不同极性组分化合物的同步分析。采用干法制备酸性硅胶柱纯化,用15 mL正己烷和15 mL二氯甲烷正己烷(1:1,V/V)混合溶剂洗脱效果良好。31种化合物在4.0~500μg/L浓度范周内线性良好,相关系数均大于0.99,回收率在71.6%~133.0%之间;相对标准偏差低于21.5%;检出限在0.09~17.0 ng/g之间。本方法应用到斑马鱼亲子代间转移研究中,对实际样品的检测良好,并发现BDE-47,6-HO-BDE-47,6-MeO-BDE-47,2’-HO BDE-28和2’-MeC-BDE 28可通过母代斑马鱼暴露后,不同程度地转移到子代中。 相似文献
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Lebedeva N. N. Mazaev V. V. Tret'yakov N. Yu. 《Russian Journal of Applied Chemistry》2001,74(8):1415-1417
Monoalkyl ethers of ethylene and triethylene glycols were prepared and tested for intensification of oil recovery. The features of oil displacement with aqueous solutions of glycol ethers from bulk models of strata and the effect of glycol ethers on acid treatment of oil-saturated samples were examined. A correlation between the structure of ether and its performance was revealed. The interphase tension at the boundary between the aqueous solution of the glycol ether and kerosene was determined. 相似文献
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蔬菜中多溴联苯醚的定量测定及其对人体的生物有效性 总被引:4,自引:1,他引:4
建立了以索氏抽提,凝胶渗透色谱及硅胶-氧化铝复合层析柱净化,测定蔬菜中13种多溴联苯醚(PBDEs)的GC-NCI MS分析方法,方法的检出限以干重计为5.4 ~15.7 pg/g,加标样品的回收率和RSD分别为78% ~97%和0.6% ~10.0%.还研究了蔬菜中的PBDEs在人胃肠中对人体的生物有效性,胡萝卜和菠菜中PBDEs的总含量分别为424.1 pg/g和981.3 pg/g,对人体的平均生物有效性分别为33.5%和2.6%,计算得到13种PBDEs在胡萝卜和菠菜中的生物有效含量分别为132.6 pg/g和26.1 pg/g,研究结果对污染物的暴露风险评估有参考价值. 相似文献
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《Tetrahedron letters》1987,28(8):853-856
Irradiation of 9-diazofluorene in the presence of epoxides yields fluorenone and an equimolar concentration of the alkene formed from the stereospecific deoxygenation of the epoxide. 相似文献
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4-肟醚基喹唑啉类化合物的合成及其抗植物病毒TMV活性 总被引:7,自引:0,他引:7
4-氯喹唑啉与取代芳香肟在碱存在下进行亲核取代反应,合成了17种新型肟醚基喹唑啉衍生物,并对其结构进行了表征。生物活性测试表明,部分化合物抗植物烟草花叶病毒活性超过抗植物病毒商品药剂2,4-二氧六氢-1,3,5-三嗪。 相似文献
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Novel ethyl 2-oxo-4,6-diaryl-1,2,3,4-tetrahydropyridine-3-carboxylate and 4,6-diaryl-3,4-dihydropyridine-2(1H)-one derivatives have been synthesized from the cyclization of adducts of diethylmalonate to chalcones with ammonium acetate. The structures were established on the basis of extensive spectroscopic methods and further confirmed by X-ray crystallographic analysis. Antibacterial activity of obtained pyridones was investigated against four human pathogen microorganisms and the compounds showed poor activity.
[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] 相似文献
19.
Theo Maulbetsch Dr. Eva Jürgens Prof. Dr. Doris Kunz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(46):10634-10640
The use of carbon monoxide as a direct reducing agent for the deoxygenation of terminal and internal epoxides to the respective olefins is presented. This reaction is homogeneously catalyzed by a carbonyl pincer-iridium(I) complex in combination with a Lewis acid co-catalyst to achieve a pre-activation of the epoxide substrate, as well as the elimination of CO2 from a γ-2-iridabutyrolactone intermediate. Especially terminal alkyl epoxides react smoothly and without significant isomerization to the internal olefins under CO atmosphere in benzene or toluene at 80–120 °C. Detailed investigations reveal a substrate-dependent change in the mechanism for the epoxide C−O bond activation between an oxidative addition under retention of the configuration and an SN2 reaction that leads to an inversion of the configuration. 相似文献