- The first synthesis of spirocyclic sulfates from tertiary cyclopropanols and their reaction with normant homocuprates
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Spirocyclic sulfates of 2- and 3-(hydroxyalkyl)cyclopropanols, obtainable through the Kulinkovich reaction from β-and γ-hydroxy carboxylic acid esters, respectively, were synthesized for the first time. The possibility of regio- and stereoselective alkyla
- Shklyaruck, Denis G.,Fedarkevich, Artsiom N.,Kozyrkov, Yurii Yu.
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Read Online
- Selective α-Methylation of Ketones
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The convenient and scalable preparative approach for the two-step α-methylation of ketones is described. The optimized protocols for regioselective preparation of enaminones with further diastereoselective and functional groups tolerant hydrogenation to α-methylketones are developed. The scope and limitations of the proposed methodology are discussed. The advantages compared to known procedures are demonstrated. The unexpected role of acetone in the hydrogenation is suggested. The evaluation of the method for both early building block synthesis and late-stage CH-functionalization is shown. The elaborate procedures' preparability and scalability are demonstrated by the synthesis of several α-methyl ketones up to 100 g amount.
- Frolov, Andriy I.,Ostapchuk, Eugeniy N.,Pashenko, Alexander E.,Chuchvera, Yaroslav O.,Rusanov, Eduard B.,Volochnyuk, Dmitriy M.,Ryabukhin, Sergey V.
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p. 7333 - 7346
(2021/06/28)
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- COMPOUNDS FOR THE TREATMENT OF PAIN
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Provided herein are compounds that are useful in the treatment of pain in a subject.
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Paragraph 2408; 2703-2704
(2019/08/20)
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- Pulling the levers of photophysics: How structure controls the rate of energy dissipation
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Internal conversion: The energy difference between the Franck-Condon and equilibrium geometries and the vibrational frequency of one or a few modes determine the relative importance of adiabatic and nonadiabatic dynamics and thus the rate of electronic en
- Kuhlman, Thomas S.,Pittelkow, Michael,Solling, Theis I.,Moller, Klaus B.
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supporting information
p. 2247 - 2250
(2013/03/28)
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- Synthesis of dimethyl glutarate from cyclobutanone and dimethyl carbonate over solid base catalysts
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A facile route for the synthesis of dimethyl glutarate (DMG) from cyclobutanone and dimethyl carbonate (DMC) in the presence of solid base catalysts has been developed. It was found that the intermediate carbomethoxycyclobutanone (CMCB) was produced from cyclobutanone with DMC in the first step, and then CMCB was further converted to DMG by reacting with a methoxide group. The role of the basic catalysts can be mainly ascribed to the activation of cyclobutanone via the abstraction of a proton in the α-position by base sites, and solid bases with moderate strength, such as MgO, favor the formation of DMG.
- Zhi, Chen,Dudu, Wu
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experimental part
p. 1834 - 1838
(2012/07/31)
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- Structure guided P1′ modifications of HEA derived β-secretase inhibitors for the treatment of Alzheimer's disease
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The synthesis and SAR of a series of BACE-1 hydroxyethyl amine inhibitors containing substitutions on a spirocyclobutyl moiety is described. Selectivity against cathepsin D, a related aspartyl protease with potential off target toxicity, and improved micr
- Monenschein, Holger,Horne, Daniel B.,Bartberger, Michael D.,Hitchcock, Stephen A.,Nguyen, Thomas T.,Patel, Vinod F.,Pennington, Lewis D.,Zhong, Wenge
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scheme or table
p. 3607 - 3611
(2012/07/17)
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- A Versatile Synthesis of Four-, Five-, and Six-membered Cyclic Ketones Using Methyl Methylthiomethyl Sulfoxide
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Cyclization of 1,n-dihaloalkanes with methyl methylthiomethyl sulfoxide in the presence of a base (n-BuLi or KH) gave three-, four-, five-, and six-membered 1-methylsulfinyl-1-methylthiocycloalkanes.These cyclization products were easily converted to the corresponding ketones by acid hydrolysis except 1-methylsulfinyl-1-methylthiocyclopropane which afforded a complicated mixture.The combination of the cyclization with the acidhydrolysis thus provides a new method for synthesizing four-, five-, and six-membered cycloalkanones.Several representative preparations, such as those of substituted cyclobutanones, 3-cyclopentanone, and tetrahydro-4-pyrone are described.
- Ogura, K.,Yamashita, M.,Suzuki, M.,Furukawa, S.,Tsuchinashi, G.
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p. 1637 - 1642
(2007/10/02)
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- Vinyl Cations. 41. Influence of 4-Aryl and 4-Alkyl Substituents on the ?-Route Solvolyses of Homopropargyl Esters
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The four 4-substituted-homopropargyl tosylates and triflates 6b-e (R=phenyl, p-tolyl, anisyl, and cyclopropyl) have been synthesized and solvolyzed under various conditions, as have 2-cyclopropyl-1-cyclobutenyl triflate (11-OTf) and nonaflate (11-ONf).In addition, the solvolyses of pent-3-yn-1-yl tosylate (6a-OTs, R=methyl) and triflate (prepared previously) are reported.The ratios of C-3 ring to C-4 ring 3 ring/C4ring)> products are recorded for the reactions in various solvents.As expected, ring closure (kΔ) increases and solvent displacement (kS, SN2) decreases with decreasing nucleophilicity of solvent.Temperature effects are noted for the sovolyses of tosylates 6a-e in 100percent TFE buffered with Na2CO3 in which kΔ increases with increasing temperature.The result is explained by decomposition of the intimate ion pair with temperature, whereupon elimination to the enyne becomes smaller and ring closure (kΔ) increases at the expense of elimination.The possibility of intervention of nonclassical vinyl cations is discussed, as are other mechanistic implications.
- Collins, Clair J.,Hanack, Michael,Stutz, Herbert,Auchter, Gerhard,Schoberth, Winfried
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p. 5260 - 5268
(2007/10/02)
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- Solvolysis of 1-pent-3-ynyl triflate. Mechanism of the homopropargyl rearrangement
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1-Pent-3-ynyl triflate (1b) was solvolyzed (25°C, 24 h) in ethanol-water with 2,6-lutidine as the buffer. Products were formed predominantly (97-98.5%) through direct substitution (ks processes) and elimination. As the water content increases, the yields of 2-methylcyclobutanone (7b) (formed through kΔ processes) also increase from 0.2% (100% ethanol) to 2.8% (50% ethanol). 1-Pent-3-ynyl triflate was solvolyzed in anhydrous trifluoroethanol (25°C, 24 h) in nine different experiments with nine different buffers. Sodium and calcium carbonate, 2,6-lutidine, pyridine, and quinoline all favored kΔ processes (88-65%), whereas potassium carbonate, triethylamine, and sodium trifluoroethoxide suppressed the formation of rearranged products. The products of the solvolyses include: 2-methylcyclobutenyl trifluoroethyl ether (5b); cyclopropyl methyl ketone (6b); 2-methylcyclobutanone (7b); pent-1-en-3-yne (13); 1-pent-3-ynol (15); 2-methylcyclobutanone bis(trifluoroethyl) acetal (16), and 1-pent-3-ynyl trifluoroethyl ether (17). In 80% trifluoroethanol-20% water (sodium carbonate buffer) the yields of rearranged products (kΔ) dropped to 46% - as expected for an increase in nucleophilicity of the solvent. A quantitative correlation exists between percent rearrangement of 1b and nucleophilicity of the solvent, as demonstrated by use of the Winstein-Grunwald-Swain equation. 1-Pent-3-ynyl triflate was synthesized with carbon-14 in the 1 position (1b-1-14C) and, separately, in the 3 position (1b-3-14C). 1-Pent-3-ynyl triflate was also prepared doubly labeled both with carbon-14 and with deuterium (1b-3-14C-1,1-d2). Isotope effects were determined for all isotope position isomers. These are: k/*k = 1.048 ± 0.003 (1b-1-14C); k/*k = 0.990 ± 0.005 (1b-3-14C); and Hk/Dk = 1.098 ± 0.004 (1b-1,1-d2). In addition, 1b-1,1-d2 on solvolysis in trifluoroethanol-sodium carbonate yields 2-methylcyclobutanone (7b) containing equal fractions of 7b-3-d2 and 7b-4-d2. The tracer and isotope effect experiments confirm the mechanistic conclusions arrived at through product distribution studies and, in addition, offer strong evidence for significant anchimeric assistance during the kΔ processes investigated.
- Hanack, Michael,Collins, Clair J.,Stutz,Benjamin, Ben M.
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p. 2356 - 2360
(2007/10/02)
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- Cyclopropanones. Formation of Vinylcyclopropanols and Their Rearrangement to Cyclobutanones
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Vinylcyclopropanols, formed by the addition of vinylmagnesium bromide to the ethyl hemiketal of cyclopropanone, may be converted to cyclobutanone derivatives on reaction with various electrophiles.The ring enlargement of 1-vinyl-2-methylcyclopropanol takes place by preferential migration of the more highly substituted carbon atom.
- Wasserman, Harry H.,Hearn, Michael J.,Cochoy, Robert E.
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p. 2874 - 2880
(2007/10/02)
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- Cyclic ketone mercaptal S-oxides
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Novel cyclic ketone mercaptal S-oxides and a process for preparing these compounds which comprises reacting formaldehyde mercaptal S-oxides with specific difunctional compounds.
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