- Conformational analysis and selective hydrolysis of 2,5-disubstituted-1,3-dioxane-2-carboxylic acid esters
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5-Alkyl-2-methyl-2-carbomethoxy-1,3-dioxanes were found to have a cis preferential configuration in the equilibrium state, and the ester hydrolysis rate of the trans-isomers was faster than that of the cis-isomers. Conformational analysis and charge calculation of the carbomethoxy group in both dioxanes elucidated this selectivity.
- Harabe, Tetsuji,Matsumoto, Takatoshi,Shioiri, Takayuki
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- Synthesis of Enantiomerically Enriched 2-Hydroxymethylalkanoic Acids by Oxidative Desymmetrisation of Achiral 1,3-Diols Mediated by Acetobacter aceti
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The stereoselective desymmetrisation of achiral 2-alkyl-1,3-diols is performed by oxidation of one of the two enantiotopic primary alcohol moieties by means of Acetobacter aceti MIM 2000/28 to afford the corresponding chiral 2-hydroxymethyl alkanoic acids (up to 94 % ee). The procedure, carried out in aqueous medium under mild conditions of pH, temperature and pressure, contributes to enlarge the portfolio of enzymatic oxidations available to organic chemists for the development of sustainable manufacturing processes.
- Brenna, Elisabetta,Cannavale, Flavia,Crotti, Michele,De Vitis, Valerio,Gatti, Francesco G.,Migliazza, Gaia,Molinari, Francesco,Parmeggiani, Fabio,Romano, Diego,Santangelo, Sara
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p. 3796 - 3803
(2016/12/24)
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- Ruthenium-catalysed synthesis of 2- and 3-substituted quinolines from anilines and 1,3-diols
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A straightforward synthesis of substituted quinolines is described by cyclocondensation of anilines with 1,3-diols. The reaction proceeds in mesitylene solution with catalytic amounts of RuCl3·xH 2O, PBu3 and MgBr2·OEt2. The transformation does not require any stoichiometric additives and only produces water and dihydrogen as byproducts. Anilines containing methyl, methoxy and chloro substituents as well as naphthylamines were shown to participate in the heterocyclisation. In the 1,3-diol a substituent was allowed in the 1- or the 2-position giving rise to 2- and 3-substituted quinolines, respectively. The best results were obtained with 2-alkyl substituted 1,3-diols to afford 3-alkylquinolines. The mechanism is believed to involve dehydrogenation of the 1,3-diol to the 3-hydroxyaldehyde which eliminates water to the corresponding α,β-unsaturated aldehyde. The latter then reacts with anilines in a similar fashion as observed in the Doebner-von Miller quinoline synthesis.
- Monrad, Rune Nygaard,Madsen, Robert
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experimental part
p. 610 - 615
(2011/02/28)
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- Synthesis and in vitro antibacterial activity of oxazolidine LBM-415 analogs as peptide deformylase inhibitors
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The drug resistant bacteria pose a severe threat to human health. The increasing resistance of those pathogens to traditional antibacterial therapy renders the identification of new antibacterial agents with novel antibacterial mechanisms an urgent need.
- Yu, Linliang,Zhou, Weicheng,Wang, Zhenyu
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p. 1541 - 1544
(2011/04/16)
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- Esters of 2,5-multisubstituted-1,3-dioxane-2-carboxylic acid: their conformational analysis and selective hydrolysis
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The carbomethoxy group at the C2 position of the 2,5-multisubstituted 1,3-dioxanes prefers the axial conformation rather than the equatorial one due to an anomeric effect. The trans isomers of the 5-monosubstituted compounds are more selectively hydrolyzed than the cis isomers. Based on the calculated results, hydrolysis to the trans isomers is attributed to the larger carbonyl charges of the trans than those of the cis isomers. The anomeric and homoanomeric effects will explain the axial preference of the carbomethoxy group and selective hydrolysis to the trans isomers. Furthermore, the calculated stability between the cis and trans isomers is in good agreement with the experimental results in the equilibrium state.
- Harabe, Tetsuji,Matsumoto, Takatoshi,Shioiri, Takayuki
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experimental part
p. 4044 - 4052
(2009/10/02)
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- Synthesis of 3-alkyl(aryl)thietanes
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A preparative procedure for the synthesis of thietanes bearing alkyl substituents in the β-position was developed. Using this procedure, 3-substituted thietanes can be obtained in four steps with an ultimate yield of > 50%. 3-R-thietanes (where R = CH3, C4H9, C5H11, C6H13, C6H 5) and the corresponding sulfoxides and sulfones were synthesized and examined. The feasibility of preparation of gem-3,3-substituted thietanes was exemplified by the synthesis of 3,3-dihexylthietane.
- Shevchenko,Volynskii
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experimental part
p. 123 - 128
(2010/02/28)
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- Mesogenic, optical, and dielectric properties of 5-substituted 2-[12-(4-pentyloxyphenyl)-p-carboran-1-yl] [1,3]dioxanes
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Two homologous series of carborane-containing dioxanes 1[n] and 2[n] (n = 1-10) were prepared and their mesogenic properties investigated. All compounds exhibit nematic behavior and three members of series 2[n] show an E phase. Numerical analysis of the clearing temperatures gave a limiting value T NI(∞) of 89 °C for series 2[n] and indicated conformational flexibility of the dioxane ring. Investigations of three-ring derivative 1[4] gave Δn = 0.17, S = 0.53, and Δε = +0.4 ± 0.1 at 85 °C. Extrapolation of dielectric data for dilute solutions of 1[4] in 6-CHBT gave Δε = +0.4 ± 0.25 at 24 °C. Modelling of dielectric results with the Maier-Meier equation demonstrated that conformers with a higher β angle are preferred, which is consistent with conformational selection for the most elongated conformers. The Royal Society of Chemistry 2006.
- Nagamine, Takashi,Januszko, Adam,Kaszynski, Piotr,Ohta, Kiminori,Endo, Yasuyuki
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p. 3836 - 3843
(2007/10/03)
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- Tethered α-boryl radical cyclizations of haloalkyl boronates
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Boroalkyl radicals readily cyclize onto alkenyl and alkynyl traps tethered via a C-B-O linkage. Oxidative cleavage of the C-B bond of the temporary connection following cyclization affords 1,3-diols in good yields.
- Batey, Robert A.,Smil, David V.
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p. 9183 - 9187
(2007/10/03)
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- Synthesis of dithioetherdithiols, potential technetium complexing agents
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The following dithioetherdithiols : 2,10-dimethyl-4,8-dithiaundecane-2,10-dithiol 1, 5-butyl-3,7-dithianonane-1,9-dithiol 2 and 4,4,6,6-tetramethyl-3,7-dithianonane-1,9-dithiol 3 have been synthesized.These compounds are very attractive as potential precu
- Alagui, A.,Apparu, M.,Pasqualini, R.,Vidal, M.
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p. 286 - 295
(2007/10/02)
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- Synthesis and Liquid Crystal Properties of Dimethylene Linked Compounds Incorporating the Cyclobutane or Spiroheptane Rings
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The preparation of sixteen dimethylene linked compounds is described heptane ring>, and a comparison is made between the transition temperatures of these compounds and those of the corresponding esters.This comparison once again highlights the fact that the cyclobutane ring should be regarded, in terms of its ability to promote nematic thermal stability, as a "chain stiffener rather than as a ring system.A comparison is also made of the nematic thermal stabilities of the trans-cyclobutane and the spiroheptane systems and of the trans-cyclohexane and the spiroundecane systems.
- Chan, L. K. M.,Gemmell, P. A.,Gray, G. W.,Lacey, D.,Toyne, K. J.
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p. 229 - 246
(2007/10/02)
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- LIQUID CRYSTAL MATERIALS WITH SULFUR ATOMS INCORPORATED IN THE PRINCIPAL STRUCTURE: 1. NEW LIQUID CRYSTAL COMPOUNDS WITH 1,3-DITHIANE RING.
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2-(p-Substituted phenyl)-5-alkyl-1,3-dithianes, new liquid crystals, were synthesized by the thioacetalization of the corresponding aldehydes and dithiols. These compounds have characteristic supercooling states, exhibit monotropic liquid crystal phases even in the case of long terminal alkyl substituents. The mesomorphic characteristics of these compounds were different from those of the corresponding 1,3-dioxanes, this must originate in the difference in the molecular width caused by the difference in the atomic volume between sulfur and oxygen.
- Haramoto,Nobe,Kamogawa
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p. 1966 - 1969
(2007/10/02)
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- LIPOPHILIC COMPLEXONES. PART 2 SYNTHESIS OF POLYETHERS DERIVED FROM 2-ALKYL-1,3-PROPANEDIOLS AND 2,2-BIS (HYDROXYMETHYL) DECANOL
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Tripodand, dipodands, and crown ethers were synthesized in reasonable yields from 2-alkyl-1,3-propanediols and 2,2-bis(hydroxymethyl)decanol.These alcohols were alkylated with chloroacetic acid, reduced, and then the oxyethylenated derivatives were conver
- Skarzewski, Jacek,Mlochowski, Jacek
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p. 309 - 312
(2007/10/02)
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- Mesomorphic Phenyl Benzoate and 1,3-Dioxane Derivatives Bearing Terminal Vinyl Group
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4-Alkylphenyl 2-chloro-4-(4-vinylbenzoyloxy) benzoates and 2-phenyl-1,3-dioxane derivatives with terminal vinyl groups were synthesized.Most of the novel compounds obtained possess characteristic mesomorphic ranges.
- Kamogawa, Hiroyoshi,Hirose, Tomoki,Nanasawa, Masato
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p. 3517 - 3518
(2007/10/02)
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- A New and Convenient Synthetic Method for Cyclopropyl Phenyl Sulfides
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The reactions of a variety of 1,3-bis(phenylthio)propanes with butyllithium have been shown to produce cyclopropyl phenyl sulfides in good to high yields.A new and convenient in situ preparation of 1-lithiocyclopropyl phenyl sulfide can be readily carried out by treating 1,3-bis(phenylthio)propane with 2 equiv. of butyllithium at 0 degC in THF.The reaction with electrophiles proceeds in good yield.O-Aryl and O-alkyl S-cyclopropyl dithiocarbonates also can be prepared in good yields. 1,2-Bis(phenylthio)ethane was converted to phenyl vinyl sulfide on treatment with butyllithium, while 1,4-bis(phenylthio)butane was recovered unchanged by a similar treatment.
- Tanaka, Kazuhiko,Uneme, Hideki,Matsui, Shuichi,Kaji, Aritsune
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p. 2965 - 2972
(2007/10/02)
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- Liquid-crystalline Heterocycloalkanes. I. Synthesis and Properties of Substituted 1,3-Dioxanes
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The synthesis of 2,5-disubstituted 1,3-dioxanes is described, their melting and clearing points and their physical properties (dielectric anisotropy, viscosity, transition enthalpies, optical birefringence) are investigated.The cyano substituted 1,3-dioxanes 5 and 7 are valuable materials for application in displays.
- Vorbrodt, H.-M.,Deresch, S.,Kresse, H.,Wiegeleben, A.,Demus, D.,Zaschke, H.
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p. 902 - 913
(2007/10/02)
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