- An efficient synthesis of (+)-subersic acid
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This paper describes a concise and practical route to (+)-subersic acid from naturally occurring (-)-Sclareol in 7 steps. The key step of this route relied on the cross coupling of the diterpene with the arene fragment using the arylation of allylic acetate followed by β-acetoxy elimination type Heck reaction. A seven-step synthetic route was developed to synthesize (+)-subersic acid from (-)-Sclareol. The cross coupling of the diterpene with the arene fragment using the arylation of allylic acetate followed by β-acetoxy elimination type Heck reaction was acted as the key reaction.
- Wang, Jing,Wang, Peiqiang,Li, Jue,Wu, Peiying,Ren, Jiangmeng,Zeng, Bubing
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Read Online
- CuLi2Cl4 catalysed cross-coupling strategy for the formal synthesis of the diterpenoid (+)-subersic acid from (?)-sclareol
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A CuLi2Cl4-catalysed regioselective cross-coupling is used in a key step leading to the concise synthesis of (+)-subersic acid with an overall yield of 25.7% from commercially available (-)-sclareol. The coupled product 15-(2-methoxy-5-carbomethoxy)phenyl-labda-8(9),13Ediene was obtained in 62% yield under CuLi2Cl4 conditions starting from 2-iodo-4-carbomethoxyanisole and 15-acetoxy-labda-8(9),13Ediene. These were derived from 4-hydroxybenzoic acid and (-)-sclareol respectively. The 15-(2-methoxy-5-carbomethoxy)phenyl-labda- 8(9),13E-diene was easily transformed into (+)-subersic acid by demethylation of the phenol ether and ester. This cross-coupling strategy showed a good functional group tolerance and various (+)-subersic acid derivatives were obtained in moderate yields.
- Wu, Qiangyong,Wang, Peiqiang,Zhou, Bin,Hua, Sikai,Ren, Jiangmeng,Zeng, Bu-Bing
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p. 394 - 397
(2017/08/07)
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- Compound for treatment or prevention of hyperuricemia or gout
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The invention discloses a compound for treatment or prevention of hyperuricemia or gout. The compound is the compound shown as formula (I) or formula (II) or pharmaceutical acceptable salts thereof. The compound or its pharmaceutical acceptable salts can be applied to urate excretion promotion so as to treat or prevent hyperuricemia or gout. (formula (1), formula (II)).
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Paragraph 0134; 0135
(2017/01/26)
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- Gold(I)-catalyzed iodination of arenes
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A wide variety of electron-rich arenes were efficiently converted into the corresponding iodinated compounds via a gold(I)-catalyzed reaction under mild conditions. Georg Thieme Verlag Stuttgart. New York.
- Leboeuf, David,Ciesielski, Jennifer,Frontier, Alison J.
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supporting information
p. 399 - 402
(2014/03/21)
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- An in situ acidic carbon dioxide/glycol system for aerobic oxidative iodination of electron-rich aromatics catalyzed by Fe(NO3)3·9H2O
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An environmentally benign CO2/glycol reversible acidic system was developed for the iron(iii)-catalyzed aerobic oxidative iodination of electron-rich aromatics without the need for any conventional acid additive or organic solvent. Notably, moderate to high isolated yields (up to 97%) of the aryl iodides were attained with comparable regioselectivity when ferric nitrate nonahydrate was used as the catalyst with molecular iodine under 1 MPa of CO2.
- Ma, Ran,Huang, Cheng-Bin,Liu, An-Hua,Li, Xue-Dong,He, Liang-Nian
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p. 4308 - 4312
(2015/01/08)
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- Mild arming and derivatization of natural products via an In(OTf) 3-catalyzed arene iodination
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Figure presented Iodination of arene-containing natural products employing N-iodosuccinimide catalyzed by In(OTf)3 at ambient temperature is reported as a versatile and mild method for natural product derivatization amenable to small scale. This process facilitates natural product derivatization of arene moieties for SAR studies, homo- and heterodimerization of natural products, and also conjugation with reporters such as biotin via subsequent metal-mediated coupling reactions.
- Zhou, Cong-Ying,Li, Jing,Peddibhotla, Satyamaheshwar,Romo, Daniel
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supporting information; experimental part
p. 2104 - 2107
(2010/09/15)
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- Reactive trityl derivatives: Stabilised carbocation mass-tags for life sciences applications
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The rational design of novel triarylmethyl (trityl)-based mass tags (MT) for mass-spectrometric (MS) applications is described. We propose a "pKR+ rule" to correlate the stability of trityl carbocations with their MS performance: trityls with higher pKR+ values ionise and desorb better. Trityl blocks were synthesised that have high pKR+ values and are stable in conditions of MS analysis; these MTs can be ionised by matrix as well as irradiation with a 337 nm nitrogen laser. 13C-Labelled tags were prepared for MS quantitation applications. Moreover, the tags were equipped with a variety of functional groups allowing conjugation with different functionalities within (bio)molecules to enhance the MS characteristics of the latter. The MS behaviour of model polycationic trityl compounds with and without the matrix was studied to reveal that poly-trityl clusters are always singly charged under the (MA)LDI-TOF conditions. Several peptide-trityl conjugates were prepared and comparisons revealed a beneficial effect of trityl tags on the conjugate detection in MS. Trityl compounds containing para-methoxy- and dimethylamine groups, as well as a xanthene fragment, showed considerable enhancement in MS detection of model peptides; thus they are promising tools for proteomic applications. Dimethoxytrityl derivatives allow one to distinguish between Arg- and Lys-containing peptides. Maleimido trityl derivatives are suitable for the efficient derivatisation of thiol-containing peptides in pyridine.
- Ustinov, Alexey V.,Shmanai, Vadim V.,Patel, Kaajal,Stepanova, Irina A.,Prokhorenko, Igor A.,Astakhova, Irina V.,Malakhov, Andrei D.,Skorobogatyi, Mikhail V.,Bernad, Pablo L.,Khan, Safraz,Shahgholi, Mona,Southern, Edwin M.,Korshun, Vladimir A.,Shchepinov, Mikhail S.
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supporting information; experimental part
p. 4593 - 4608
(2009/03/12)
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- Oxidative iodination of deactivated arenes in concentrated sulfuric acid with I2/NaIO4 and KI/NaIO4 iodinating systems
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Deactivated arenes were mono- or diiodinated with strong electrophilic I+ reagents, which were prepared from NaIO4 and either I2 or KI in concentrated H2SO4 (minimum 95% by weight). In general a small excess of the dark brown iodinating solution was used (1.1/1.5 equivalents, for nitrobenzene two equivalents was required). The iodinations were conducted at 25-30 °C with a reaction time of 1-2 hours using either a 'direct' or an 'inverse' method of aromatic iodination to give mono- or diiodinated pure products in 31-91% optimized yields. Georg Thieme Verlag Stuttgart.
- Kraszkiewicz, Lukasz,Sosnowski, Maciej,Skulski, Lech
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p. 1195 - 1199
(2007/10/03)
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- Eco-friendly oxidative iodination of various arenes with sodium percarbonate as the oxidant http://www.mdpi.org
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Six easy laboratory procedures are presented for the oxidative iodination of various aromatics, mostly arenes, with either molecular iodine or potassium iodide (used as the sources of iodinating species, I+ or I 3+), in the presence of sodium percarbonate (SPC), a stable, cheap, easy to handle, and eco-friendly commercial oxidant.
- Zielinska, Agnieszka,Skulski, Lech
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p. 1307 - 1317
(2007/10/03)
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- Derivatised molecules for mass spectrometry
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Compounds of formula (IIa): are provided where:X is a group capable of being cleaved from the α-carbon atom to form an ion of formula (I')C is a carbon atom bearing a single positive charge or a single negative charge; The invention further provides compounds of formula (IIb): where:X is a counter-ion to C. The compounds of formula (IIa) and (IIb) may form ions of formula (I') by either cleaving the C-X bond between X and the α-carbon atoms in the case of the compounds of formula (IIa) or dissociating X in the case of compounds of formula (IIb).
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- Easy, inexpensive and effective oxidative iodination of deactivated arenes in sulfuric acid
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Two 'model' deactivated arenes, benzoic acid and nitrobenzene, were effectively monoiodinated within 1 h at 25-30 °C, with strongly electrophilic I+ reagents, prior prepared from diiodine and various oxidants (CrO3, KMnO4, active MnO2, HIO 3, NaIO3, or NaIO4) in 90% (v/v) concd sulfuric acid (ca. 75 mol% H2SO4). Next, an I2/ NaIO3/90% (v/v) concd H2SO4 exemplary system was used to effectively mono- or diiodinate a number of deactivated arenes. All former papers dealing with the direct iodination of deactivated arenes are briefly reviewed.
- Kraszkiewicz, Lukasz,Sosnowski, MacIej,Skulski, Lech
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p. 9113 - 9119
(2007/10/03)
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- Eco-friendly Oxidative Iodination of Various Arenes with a Urea-Hydrogen Peroxide Adduct (UHP) as the Oxidant
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Three easy eco-friendly laboratory procedures are presented for the oxidative iodination of various activated and deactivated arenes with molecular iodine, in the presence of UHP (percarbamide), a stable, strongly H-bonded, solid urea-hydrogen peroxide adduct as the oxidant.
- Lulinski, Piotr,Kryska, Anna,Sosnowski, Maciej,Skulski, Lech
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p. 441 - 445
(2007/10/03)
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- A New Preparative Route to Substituted Dibenzofurans by Benzannulation Reaction. An Application to the Synthesis of Cannabifuran
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A new regioselective pathway to substituted dibenzofuran derivatives is described here. According to this procedure substituted 1-acetoxy-3- alkoxycarbonyl dibenzofurans are obtained by treatment of 6-(2-methoxyaryl)-3- alkoxycarbonylhex-3-en-5-ynoic acids with acetic anhydride in the presence of sodium acetate. The latter acids are prepared from the easily available substituted o-iodo-anisoles by Sonogashira coupling with propargylic alcohol and Wittig reaction as the key steps. The described benzannulation reaction proceeds in regioselective fashion and a range of substituents are tolerated. Its synthetic utility is demonstrated by a new synthesis of cannabifuran, a naturally occurring dibenzofuran.
- Serra, Stefano,Fuganti, Claudio
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p. 2005 - 2008
(2007/10/03)
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- Reactivity and synthetic utility of 1-(arenesulfonyloxy) benziodoxolones
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The reactivity and synthetic use of 1-(arenesulfonyloxy)benziodoxolones were studied. In the presence of iodine, 1-(arenesulfonyloxy)benziodoxolones iodinated various aromatics to give iodoarenes in moderate to good yields. In particular, 1-(p-chlorobenzenesulfonyloxy)benziodoxolone showed the best reactivity. Using a halide salt such as lithium bromide or lithium chloride instead of iodine, the corresponding aryl bromides and chlorides were also obtained in good yields. In the absence of aromatics, 1- (arenesulfonyloxy)benziodoxolones gave rise to desulfonyloxyiodination reactions to give the corresponding aryl iodides via electrophilic ipso substitution on the aromatic rings. Furthermore, the l-(p- toluenesulfonyloxy)benziodoxolone/iodine system iodotosyloxylated alkynes in good yields. These reactions proceeded via the formation of arenesulfonyl hypoiodites.
- Muraki, Takahito,Togo, Hideo,Yokoyama, Masataka
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p. 2883 - 2889
(2007/10/03)
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- Iodothyronine Deiodinase Mimics. Deiodination of o,o'-Diiodophenols by Selenium and Tellurium Reagents
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To better understand, and in the extension mimic, the action of the three selenium-containing iodothyronine deiodinases, o,o'-diiodophenols were reacted under acidic conditions with sodium hydrogen telluride, benzenetellurol, sodium hydrogen selenide, or benzeneselenol and under basic conditions with the corresponding deprotonated reagents. Sodium hydrogen telluride was found to selectively remove one iodine from a variety of 4-substituted o,o'-diiodophenols, including a protected form of thyroxine (T4). Thus, it mimics the D1 variety of the iodothyronine deiodinases. Sodium telluride was a more reactive deiodinating agent toward o,o'-diiodophenols, often causing removal of both halogens. Benzenetellurol and sodium benzenetellurolate sometimes showed useful selectivity for monodeiodination. However, the products were often contaminated by small amounts of organotellurium compounds. Sodium hydrogen selenide, sodium selenide, benzeneselenol, and sodium benzeneselenolate were essentially unreactive toward o,o'-diiodophenols. To gain more insight into thyroxine inner-ring deiodination, substituted 2,6-diiodophenyl methyl ethers were treated with some of the chalcogen reagents. Reactivity and selectivity for monodeiodination varied considerably depending on the substituents attached to the aromatic nucleus. In general, it was possible to find reagents that could bring about the selective mono- or dideiodination of these substrates.
- Vasil'ev, Andrei A.,Engman, Lars
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p. 3911 - 3917
(2007/10/03)
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