- A Practical, Component-Based Synthetic Route to Methylthiolincosamine Permitting Facile Northern-Half Diversification of Lincosamide Antibiotics
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The development of a flexible, component-based synthetic route to the amino sugar fragment of the lincosamide antibiotics is described. This route hinges on the application and extension of nitroaldol chemistry to forge strategic bonds within complex amino sugar targets and employs a glycal epoxide as a versatile glycosyl donor for the installation of anomeric groups. Through building-block exchange and late-stage functionalization, this route affords access to a host of rationally designed lincosamides otherwise inaccessible by semisynthesis and underpins a platform for the discovery of new lincosamide antibiotics.
- Mitcheltree, Matthew J.,Stevenson, Jack W.,Pisipati, Amarnath,Myers, Andrew G.
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supporting information
p. 6829 - 6835
(2021/05/29)
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- BICYCLIC KETONE COMPOUNDS AND METHODS OF USE THEREOF
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The invention provides novel compounds having the general formula (I): (I) wherein R1, the A ring and the B ring are as described herein, pharmaceutical compositions including the compounds, and methods of using the compounds.
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Page/Page column 250; 251
(2019/02/02)
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- LINCONSAMIDE ANTIBIOTICS AND USES THEREOF
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Provided are lincosamide compounds for the treatment of infectious diseases. The lincosamides described herein are modified at the amino acid (southern) region. The lincosamides may have further modification at the C-1 and C-7 positions of the aminooctose (northern) region, thus distinguishing them from lincomycin and clindamycin. Also provided are methods for preparing the lincosamide compounds, pharmaceutical compositions comprising the lincosamide compounds, and methods of treating infectious diseases using the disclosed lincosamide compounds.
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Paragraph 00411
(2019/02/25)
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- Solvent-Free Henry and Michael Reactions with Nitroalkanes Promoted by Potassium Carbonate as a Versatile Heterogeneous Catalyst
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The use of a simple weak inorganic base such as potassium carbonate facilitated the formation of carbon-carbon bonds through both the Henry and the Michael reactions with nitrocompounds. The application of this catalyst under environmentally friendly solventless heterogeneous conditions gave satisfactory to good yields of β-nitroalcohols, involving aliphatic and aromatic starting materials, as well as high to excellent yields in the formation of Michael adducts using several different Michael acceptors and nitroalkanes.
- Bosica, Giovanna,Polidano, Kurt
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- Lewis acid mediated intramolecular C-O bond formation of alkanol-epoxide leading to substituted morpholine and 1,4-oxazepane derivatives: Total synthesis of (±)-Viloxazine
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Substituted morpholines have been efficiently synthesised in good yields from nitrogen tethered alkanol-epoxide mediated by boron trifluoride etherate. The methodology has been used for the total synthesis of (±)-viloxazine.
- Ghosh, Priya,Deka, Manash J.,Saikia, Anil K.
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p. 690 - 698
(2016/01/15)
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- Highly enantioselective asymmetric Henry reaction catalyzed by novel chiral phase transfer catalysts derived from cinchona alkaloids
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A new type of di-site chiral phase transfer catalyst has been designed and synthesized from cinchona alkaloids as a chiral precursor. The prepared catalysts are applied in the asymmetric Henry reaction to a wide range of aldehydes using mild concentration
- Vijaya, Ponmuthu Kottala,Murugesan, Sepperumal,Siva, Ayyanar
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supporting information
p. 10101 - 10109
(2016/11/06)
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- Novel integrated carbon particle based three dimensional anodes for the electrochemical degradation of reactive dyes
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Three-dimensional carbon bed electrochemical reactors have been recently applied for the degradation of several organic pollutants. However, the carbon particles in such reactors slowly undergo attrition. We fabricated a novel flow-through three-dimensional anode using granular activated carbon (GAC) particles and polyvinylidene fluoride (PVDF) binder that potentially avoids such attrition. Optimization of the composition of GAC and PVDF with respect to mechanical integrity and electrical conductivity is reported. The anodes were tested in the electro oxidation of the reactive dyes: Reactive Orange-16 (RO-16), Reactive Red-2 (RR-2), and Reactive Blue-4 (RB-4). A tentative mechanism of dye degradation was proposed based on the observed role of the supporting electrolyte and the cyclic voltammetric, UV-vis, FT-IR and GC-MS data. The decolorization efficiencies were 75 ± 3, 81 ± 5 and 88 ± 4% for RB-4, RO-16 and RR-2, respectively. The integrated 3-D anodes are advantageous because of the absence of carbon attrition, which is otherwise found when a bed of GAC is used in the electrochemical reactors.
- Misra, Rohit,Neti, Nageswara Nao,Dionysiou, Dionysios D.,Tandekar, Mahendra,Kanade, Gajanan S.
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p. 10799 - 10808
(2015/02/05)
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- Asymmetric N-heterocyclic carbene catalyzed addition of enals to nitroalkenes: Controlling stereochemistry via the homoenolate reactivity pathway to access δ-lactams
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An asymmetric intermolecular reaction between enals and nitroalkenes to yield δ-nitroesters has been developed, catalyzed by a novel chiral N-heterocyclic carbene. Key to this work was the development of a catalyst that favors the δ-nitroester pathway over the established Stetter pathway. The reaction proceeds in high stereoselectivity and affords the previously unreported syn diastereomer. We also report an operationally facile two-step, one-pot procedure for the synthesis of δ-lactams.
- White, Nicholas A.,Dirocco, Daniel A.,Rovis, Tomislav
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supporting information
p. 8504 - 8507
(2013/07/19)
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- Tin(II)chloride mediated addition reaction of bromonitromethane to aldehydes
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Bromonitromethane adds to aliphatic aldehydes in the presence of tin(II) chloride to yield β-nitro alcohols via a Reformatsky-type reaction in high yields, while aromatic aldehydes give low yields. The products were characterized by IR, NMR, and mass spectroscopy and by elemental analysis.
- Mahasneh, Ali S.
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p. 416 - 418
(2007/10/03)
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- Nitroaldol-reaction of aldehydes in the presence of non-activated Mg:Al 2:1 hydrotalcite; A possible new mechanism for the formation of 2-aryl-1,3-dinitropropanes
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Commercially available, non-activated 2:1 Mg:Al hydrotalcite catalyzes the nitroaldol reaction between a variety of aromatic and aliphatic aldehydes and simple nitroalkanes such as nitromethane and nitroethane. A new mechanism is proposed for the formation of the 1,3-dinitropropanes. The threo/erythro diastereoselectivity of the nitroethane-adducts was determined by 1H NMR spectroscopy and was found to range from 50:50 to 70:30. The substituents of the aromatic aldehydes influenced the isomer ratio.
- Cwik, Agnieszka,Fuchs, Aliz,Hell, Zoltán,Clacens, Jean-Marc
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p. 4015 - 4021
(2007/10/03)
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- Lipase catalysed resolution of nitro aldol adducts
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The kinetic resolution of a range of 1-nitro-2-alkanols by lipase-catalysed esterification using various lipases and succinic anhydride as an acyl donor has been studied. E values of up to 100 were obtained with Novozym 435 in the resolution of 1-nitro-2-pentanol with succinic anhydride in TBME. Acylation with succinic anhydride proved much more enantioselective than with vinyl acetate.
- Sorgedrager, Menno J.,Malpique, Rita,Van Rantwijk, Fred,Sheldon, Roger A.
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p. 1295 - 1299
(2007/10/03)
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- Enantioselective synthesis of α-amino acids and monosubstituted 1,2- diamines by conjugate addition of 4-phenyl-2-oxazolidinone to nitroalkenes
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The addition of the potassium salt of (R)- or (S)-4-phenyl-2- oxazolidinone to monosubstituted nitroalkenes proceeded with very good diastereoselectivity. Several of the addition products were converted into α-amino acids and monosubstituted 1,2-diamines of high enantiomeric purity.
- Lucet, Denis,Sabelle, Stephane,Kostelitz, Olivier,Le Gall, Thierry,Mioskowski, Charles
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p. 2583 - 2591
(2007/10/03)
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- Facile synthesis of 2-nitroalkanols by tetramethylguanidine (TMG)-catalyzed addition of primary nitroalkanes to aldehydes and alicyclic ketones
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Tetramethylguanidine-catalyzed addition of primary nitroalkanes to aldehydes and alicylic ketones constitutes a practical means to perform the nitro-aldol reaction (Henry reaction). The very mild conditions employed, together with the short reaction times, make the procedure tolerant of a range of functionalities and highly versatile for the synthesis of a variety of 2-nitroalkenols.
- Simoni, Daniele,Invidiata, Francesco Paolo,Manfredini, Stefano,Ferroni, Roberto,Lampronti, Ilaria,Roberti, Marinella,Pollini, Gian Piero
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p. 2749 - 2752
(2007/10/03)
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- Preparation of 3-dihaloacetyl oxazolidines
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The disclosure herein relates to a new process for the preparation of 3-dihaloacetyl (un)substituted oxazolidine compounds by the catalytic hydrogenation of nitroalcohols with aldehydes or ketones followed by reaction with a dihaloacetyl halide.
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- Effect of solvent structure on enantioselectivity of lipase-catalyzed transesterification
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Enantioselectivity in transesterification of a secondary alcohol under lipase-catalysis is largely affected by the solvent used. Two groups of solvents, cyclic and acyclic, show different feature on enantioselectivity.
- Nakamura,Takebe,Kitayama,Ohno
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p. 4941 - 4944
(2007/10/02)
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- Addition of aldehydes to organic compounds having a carbon-hydrogen bond activated by a nitro or nitrile group
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Low valent transition metal complexes containing small cone angle phosphine or arsine ligands efficiently catalyze addition of aldehydes to compounds or groups having a C--H bond activated by a nitro or nitrile group, to provide nitroalcohols or cyanohydrins, respectively.
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- Solvent Effects on Equilibria of Addition of Nucleophiles to Acetaldehyde and the Hydrophilic Character of Diols
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Equilibria of addition of water, methanol, methanethiol, ammonia, methylamine, nitromethane, and ethylene glycol to acetaldehyde have been compared in water and in chloroform, and the partition coefficients of reactants and products between the two solvents have been estimated by direct and indirect methods.Single additions of oxygen nucleophiles were found to proceed equally favorably in either solvent, whereas single additions of sulfur, nitrogen, and carbon nucleophiles proceeded much further toward completion in water than in chloroform.Equilibria of acetal formation, involving methanol or ethylene glycol, were somewhat more favorable in chloroform than in water.Reexamination of the vapor pressures of ethylene glycol and related compounds over water indicated that their hydrophilic character was greater than had been supposed.
- Bone, Roger,Cullis, Paul,Wolfenden, Richard
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p. 1339 - 1343
(2007/10/02)
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- Synthesis of Norbornanones with a Geminal Dimethyl Group
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The synthesis of gem-dimethylnorbornanones is described.One synthetic pathway after a Diels-Alder reaction involves the transformation of the nitro group into the oxo group with subsequent methylation into the geminal dimethyl product.A shorter way by -cycloaddition of cyclopentadiene with a suitable dimethylated dienophile (e.g. 2-methyl-1-nitropropene) failed, probably by steric hindrance of the dienophile. 7-Oxanorbornanones with a gem -dimethyl group could not be prepared.A second synthetic approach to gem-dimethylnorbornanones is opened by Lewis acid catalyzed rearrangement of cyclohexenylcarbaldehydes. - Keywords: Camphenilone; Diels-Alder reaction; Homonorbornanone; α-Methylation of carbonyls; Nef-reaction; Norepifenchone
- Buchbauer, Gerhard,Dworan, Erich
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p. 1165 - 1174
(2007/10/02)
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- The Electronic Interaction between the Methyl Group and Trigonal Carbon
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The nature of the interaction between methyl and a trigonal carbon has been examined by the effect of substituents on the methyl rotational barrier.Barriers have been measured for para-substituted toluenes and for cis- and trans-substituted propenes by the motional effects of methyl rotation on dipole-dipole spin-lattice relaxation.The toluene barriers exhibit a fair correlation with ?I and a very poor one with ?R.Thus hyperconjugation cannot be a major factor in determining the methyl rotational barrier.The propene barriers, particularly in the cis series, also correlate with ?I but have a better correlation with ?R than do the toluenes.Examination of all the 13C chemical shifts showed that the rotational barriers correlate only with the ortho carbon in the toluenes and with the 2-carbon (methyl substituted) in the propenes.These results suggest that the methyl rotational barrier is primarily sensitive to the nature of the ortho C-H bond in the toluenes and the α-C-H bond in the propenes.The ?R and ?I correlations are in accord with this model, since the ortho toluene carbon cannot interact directly through resonance with the para substituent but must depend on polar interactions.In the propenes, on the other hand, electron density at the α-carbon is determined by both inductive and resonance effects.The major factor in determining these barriers is the electron density at the critical carbon center, which is the ortho carbon for the toluenes and the α-carbon for the propenes.
- Lambert, Joseph B.,Nienhuis, Ronald J.
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p. 6659 - 6665
(2007/10/02)
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