17 research outputs found

    Iron-Catalyzed, Chelation-Induced Remote C–H Allylation of Quinolines via 8‑Amido Assistance

    No full text
    An iron-catalyzed, 8-amido-enabled regiodivergent C–H allylation of quinolines is described. This reaction represents a rare example of chelation-induced geometrically inaccessible C–H functionalization, allowing for the highly regio- and stereoselective preparation of either the C5- or the C4-allylated quinoline scaffolds regiocontrolled by the catalytic systems

    Aminocyanation by the Addition of N–CN Bonds to Arynes: Chemoselective Synthesis of 1,2-Bifunctional Aminobenzonitriles

    No full text
    An efficient aminocyanation by the direct addition of aryl cyanamides to arynes is described, enabling incorporation of highly useful amino and cyano groups synchronously via cleavage of inert N–CN bonds, affording synthetically useful 1,2-bifunctional aminobenzonitriles. The postsynthetic functionalization of the aminocyanation products allows diverse formation of synthetically important derivatives such as drug molecule Ponstan and fused heterocycles

    Iron-Catalyzed Regio- and Stereoselective Chlorosulfonylation of Terminal Alkynes with Aromatic Sulfonyl Chlorides

    No full text
    Terminal alkynes react with aromatic sulfonyl chlorides in the presence of an iron(II) catalyst and a phosphine ligand to give (<i>E</i>)-β-chlorovinylsulfones with 100% regio- and stereoselectivity. Various functional groups, such as chloride, bromide, iodide, nitro, ketone, and aldehyde, are tolerated under the reaction conditions. Addition of tosyl chloride to a 1,6-enyne followed by radical 5-<i>exo</i>-<i>trig</i> cyclization gave an exocyclic alkenylsulfone

    Site-Selective Silylation of Aliphatic C–H Bonds Mediated by [1,5]-Hydrogen Transfer: Synthesis of α‑Sila Benzamides

    No full text
    The first example of site-selective silylation of C­(sp<sup>3</sup>)–H bonds mediated by a [1,5]-hydrogen transfer is reported. This reaction occurs selectively at the α-position of benzamides with a combination of <i>tert</i>-butylmagnesium chloride and a catalytic amount of 4,4′-di-<i>tert</i>-butylbipyridine (dtbpy) ligand and provides a facile route for the creation of biologically interesting α-sila benzamides. Late-stage functionalization of the incorporated silyl moieties facilitates the synthesis of <i>N</i>-formyl, <i>cis</i>-enamine, β-hydroxyl, amino, and pyrrole-containing derivatives

    Site-Selective Silylation of Aliphatic C–H Bonds Mediated by [1,5]-Hydrogen Transfer: Synthesis of α‑Sila Benzamides

    No full text
    The first example of site-selective silylation of C­(sp<sup>3</sup>)–H bonds mediated by a [1,5]-hydrogen transfer is reported. This reaction occurs selectively at the α-position of benzamides with a combination of <i>tert</i>-butylmagnesium chloride and a catalytic amount of 4,4′-di-<i>tert</i>-butylbipyridine (dtbpy) ligand and provides a facile route for the creation of biologically interesting α-sila benzamides. Late-stage functionalization of the incorporated silyl moieties facilitates the synthesis of <i>N</i>-formyl, <i>cis</i>-enamine, β-hydroxyl, amino, and pyrrole-containing derivatives

    Synthesis of 2‑Benzylphenyl Ketones by Aryne Insertion into Unactivated C–C Bonds

    No full text
    A transition-metal-free procedure to access to functionalized 2-benzylphenyl ketones is described by direct insertion of arynes into benzylic C–C bonds. This reaction was promoted by cesium fluoride at room temperature, allowing the products to form in high selectivity and achieve good functional group tolerance

    Synthesis of 2‑Benzylphenyl Ketones by Aryne Insertion into Unactivated C–C Bonds

    No full text
    A transition-metal-free procedure to access to functionalized 2-benzylphenyl ketones is described by direct insertion of arynes into benzylic C–C bonds. This reaction was promoted by cesium fluoride at room temperature, allowing the products to form in high selectivity and achieve good functional group tolerance

    Regio- and Chemoselective Kumada–Tamao–Corriu Reaction of Aryl Alkyl Ethers Catalyzed by Chromium Under Mild Conditions

    No full text
    Acting as an environmentally benign synthetic tool, the cross-coupling reactions with aryl ethers via C–O bond activation have attracted broad interest. However, the functionalizations of C–O bonds are mainly limited to nickel catalysis, and selectivity has long been a prominent challenge when several C–O bonds are present in the one molecule. We report here the first chromium-catalyzed selective cross-coupling reactions of aryl ethers with Grignard reagents by the cleavage of C–O­(alkyl) bonds. Diverse transformations were achieved using simple, inexpensive chromium­(II) precatalyst combining imino auxiliary at room temperature. It offers a new avenue for buildup functionalized aromatic aldehydes with high efficiency and selectivity

    Predisposing factors of recurrent vulvovaginal candidiasis III.

    No full text
    SOUHRN V práci jsme se zabývali problematikou rekurentní vulvovaginální kandidózy. Vulvovaginální kandidóza patří mezi nejběžnější genitální infekce. Předpokládá se, že 75% žen v reprodukčním věku minimálně 1krát za život prodělá ataku VVK. RVVK je nejčastěji definována čtyřmi nebo více atakami symptomatických vaginálních kandidóz během jednoho roku. Incidence tohoto onemocnění není přesně známá, předpokládá se okolo 5%, některé studie uvádějí až 8% žen v reprodukčním věku. Naše studie uvádí incidenci 7,6%. Pro účel této práce byly vypracovány dotazníky, pomocí nichž jsme se snažili zjistit možné predispoziční faktory tohoto onemocnění. Každý dotazník se skládal z 17 stran a obsahoval 49 otázek. Plné znění dotazníku je uvedeno v příloze. Dotazník obsahoval 15 silně orámovaných otázek určených jen ženám, které mají zkušenost s opakovaným kvasinkovým zánětem. Hodnotili jsme skupinu 184 žen, které vyplnily náš dotazník (návratnost byla 184 ze 199 dotazníků, což je 92,5%). Při vyhodnocování otázek dotazníku jsme popsali několik faktorů, které zvyšují riziko výskytu RVVK, jsou to zejména tyto: konzumace potravin s vysokým obsahem sacharidů, trvalé používáni intimek i mimo menstruaci, dlouhá horká sprcha, nošení těsných kalhot, kouření cigaret, vyšší počet sexuálních partnerů, vyholování ochlupení v klíně z větší...1 ABSTRACT In this study we are dealing with problems of recurrent vulvovaginal candidiasis. Vulvovaginal candidiasis is one of the most frequent genital infections. It is hypothesized that 75% of woman experience during their reproductive age at least 1 episode of VVC in their lifetime. RVVC can be defined as four or more attacks of symptomatic vulvovaginal candidiasis in 12 month period. The true incidence of RVVC remains unknown. Estimates over many years suggest that the incidence is approximately 5%, another recent study determined that the incidence is approximately 8% woman during their reproductive age. Our study determined that the incidence is approximately 7,6%. For purpose of this study were made questionnaires, which help to examine possible risk factors of RVVC. Each questionnaire is composed of 17 pages and contains 49 questions. Fulltext of the questionnaire is showed in enclosure. Questionnaire contain 15 heavily-circumscribed questions addressed only to woman, that have experience repeated episodes of vulvovaginal candidiasis. A sample of 199 woman were interviewed, 184 of them completed our questionnaire (92,5%). By evaluation of the questionnaire we have described number of factors, which increase risk of RVVC, these are primarily: diet high in sugar, continuous use of panty-liners in...Katedra biologických a lékařských vědDepartment of Biological and Medical SciencesFaculty of Pharmacy in Hradec KrálovéFarmaceutická fakulta v Hradci Králov

    Kumada Arylation of Secondary Amides Enabled by Chromium Catalysis for Unsymmetric Ketone Synthesis under Mild Conditions

    No full text
    The synthesis of aromatic ketones by chromium-catalyzed Kumada arylation of secondary amides with organomagnesium reagents is described. This reaction was enabled by using low-cost chromium­(III) salt as a precatalyst, combined with trimethylsilyl chloride as an additive, and presents a rare example of catalytic transformation of secondary amides to ketones at room temperature. It was shown that catalytically active low-valent chromium species might be responsible for the amide–ketone exchange by mechanism involving the activation of benzimidate intermediate
    corecore