- Preparation of Primary and Secondary Dialkylmagnesiums by a Radical I/Mg-Exchange Reaction Using sBu2Mg in Toluene
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The treatment of primary or secondary alkyl iodides with sBu2Mg in toluene (25–40 °C, 2–4 h) provided dialkylmagnesiums that underwent various reactions with aldehydes, ketones, acid chlorides or allylic bromides. 3-Substituted secondary cyclohexyl iodides led to all-cis-3-cyclohexylmagnesium reagents under these exchange conditions in a highly stereoconvergent manner. Enantiomerically enriched 3-silyloxy-substituted secondary alkyl iodides gave after an exchange reaction with sBu2Mg stereodefined dialkylmagnesiums that after quenching with various electrophiles furnished various 1,3-stereodefined products including homo-aldol products (99 % dr and 98 % ee). Mechanistic studies confirmed a radical pathway for these new iodine/magnesium-exchange reactions.
- Knochel, Paul,Lutter, Ferdinand H.,Sunagatullina, Alisa S.
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- Acridine Orange Hemi(Zinc Chloride) Salt as a Lewis Acid-Photoredox Hybrid Catalyst for the Generation of α-Carbonyl Radicals
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A readily accessible organic-inorganic hybrid catalyst is reported for the reductive fragmentation of α-halocarbonyl compounds. The robust hybrid catalyst is a self-stabilizing combination of ZnCl2 Lewis acid and acridine orange as the photoactive organic dye. Mechanistic specifics of this hybrid catalyst have been studied in detail using both photophysical and electrochemical experiments. A systematic study enabled the discovery of the appropriate Lewis acid for the effective LUMO stabilization of α-halocarbonyl compounds and thereby lowering of reduction potential within the range of a standard organic dye. This strategy resolves the issues like dehalogenative hydrogenation or homo-coupling of alkyl radicals by guiding the photoredox cycle through an oxidative quenching pathway. The cooperativity between the photoactive organic dye and the Lewis acid counterparts empowers functionalization with a wide range of coupling partners through efficient and controlled generation of alkyl radicals and serves as an appropriate alternative to the expensive late transition metal-based photocatalysts. To demonstrate the application potential of this cooperative catalytic system, four different synthetic transformations of α-carbonyl bromides were explored with broad substrate scopes.
- Das, Sanju,De Sarkar, Suman,Mandal, Tanumoy
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supporting information
(2021/12/10)
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- Ruthenium-catalyzed room-temperature coupling of α-keto sulfoxonium ylides and cyclopropanols for δ-diketone synthesis
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Previous transition metal-catalyzed synthesis processes of δ-diketones are plagued by the high cost of the rhodium catalyst and harsh reaction conditions. Herein a low-cost, room temperature ruthenium catalytic method is developed based on the coupling of α-keto sulfoxonium ylides with cyclopropanols. The mild protocol features a broad substrate scope (47 examples) and a high product yield (up to 99%). Mechanistic studies argue against a radical pathway and support a cyclopropanol ring opening, sulfoxonium ylide-derived carbenoid formation, migratory insertion C-C bond formation pathway.
- Fan, Shuaixin,Fang, Lili,Li, Tielei,Wu, Weiping,Zhu, Jin
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supporting information
p. 7386 - 7389
(2021/08/03)
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- Modular Synthesis of Alkenyl Sulfamates and β-Ketosulfonamides via Sulfur(VI) Fluoride Exchange (SuFEx) Click Chemistry and Photomediated 1,3-Rearrangement
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Herein, we report a synthesis of medicinally relevant β-ketosulfonamides via a photomediated 1,3-rearrangement of alkenyl sulfamates. This protocol tolerates a wide array of sensitive functional groups including alkenes, alkynes, and nitrogen-based heterocycles. Additionally, this work provides a general approach toward alkenyl sulfamates via a two-step Sulfur(VI) Fluoride Exchange (SuFEx) sequence capitalizing on SO2F2 as a linchpin to efficiently couple readily available ketones and amines without a large excess of either partner.
- Sousa E Silva, Felipe Cesar,Doktor, Katarzyna,Michaudel, Quentin
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supporting information
p. 5271 - 5276
(2021/07/20)
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- Selective electrochemical oxidation of aromatic hydrocarbons and preparation of mono/multi-carbonyl compounds
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A selective electrochemical oxidation was developed under mild condition. Various mono-carbonyl and multi-carbonyl compounds can be prepared from different aromatic hydrocarbons with moderate to excellent yield and selectivity by virtue of this electrochemical oxidation. The produced carbonyl compounds can be further transformed into α-ketoamides, homoallylic alcohols and oximes in a one-pot reaction. In particular, a series of α-ketoamides were prepared in a one-pot continuous electrolysis. Mechanistic studies showed that 2,2,2-trifluoroethan-1-ol (TFE) can interact with catalyst species and generate the corresponding hydrogen-bonding complex to enhance the electrochemical oxidation performance. [Figure not available: see fulltext.]
- Li, Zhibin,Zhang, Yan,Li, Kuiliang,Zhou, Zhenghong,Zha, Zhenggen,Wang, Zhiyong
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p. 2134 - 2141
(2021/09/29)
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- Method for hydrogenolysis of halides
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The invention discloses a method for hydrogenolysis of halides. The invention discloses a preparation method of a compound represented by a formula I. The preparation method comprises the following step: in a polar aprotic solvent, zinc, H2O and a compound represented by a formula II are subjected to a reaction as shown in the specification, wherein X is halogen; Y is -CHRR or R; hydrogenin H2O exists in the form of natural abundance or non-natural abundance. According to the preparation method, halide hydrogenolysis can be simply, conveniently and efficiently achieved through a simple and mild reaction system, and good functional group compatibility and substrate universality are achieved.
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Paragraph 0230-0232; 0316-0318
(2021/01/11)
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- Dehalogenative Deuteration of Unactivated Alkyl Halides Using D2O as the Deuterium Source
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The general dehalogenation of alkyl halides with zinc using D2O or H2O as a deuterium or hydrogen donor has been developed. The method provides an efficient and economic protocol for deuterium-labeled derivatives with a wide substrate scope under mild reaction conditions. Mechanistic studies indicated that a radical process is involved for the formation of organozinc intermediates. The facile hydrolysis of the organozinc intermediates provides the driving force for this transformation.
- Xia, Aiyou,Xie, Xin,Hu, Xiaoping,Xu, Wei,Liu, Yuanhong
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p. 13841 - 13857
(2019/10/17)
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- Electrochemically Oxidative α-C-H Functionalization of Ketones: A Cascade Synthesis of α-Amino Ketones Mediated by NH4I
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An efficient electrochemical protocol for the synthesis of α-amino ketones via the oxidative cross-dehydrogenative coupling of ketones and secondary amines has been developed. The electrochemistry performs in a simple undivided cell using NH4I
- Liang, Sen,Zeng, Cheng-Chu,Tian, Hong-Yu,Sun, Bao-Guo,Luo, Xu-Gang,Ren, Fa-Zheng
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p. 11565 - 11573
(2016/12/09)
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- Transition-Metal-Free α-Arylation of Enolizable Aryl Ketones and Mechanistic Evidence for a Radical Process
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The α-arylation of enolizable aryl ketones can be carried out with aryl halides under transition-metal-free conditions using KOtBu in DMF. The α-aryl ketones thus obtained can be used for step- and cost-economic syntheses of fused heterocycles and Tamoxifen. Mechanistic studies demonstrate the synergetic role of base and solvent for the initiation of the radical process.
- Pichette Drapeau, Martin,Fabre, Indira,Grimaud, Laurence,Ciofini, Ilaria,Ollevier, Thierry,Taillefer, Marc
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supporting information
p. 10587 - 10591
(2015/09/02)
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- A chemoselective α-aminoxylation of aryl ketones: a cross dehydrogenative coupling reaction catalysed by Bu4NI
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Tetrabutyl ammonium iodide (TBAI) catalyzed α-aminoxylation of ketones using aq. TBHP as an oxidant has been accomplished. We have shown that the CDC (cross dehydrogenative coupling) reactions of ketones with N-hydroxyimidates such as N-hydroxysuccinimide (NHSI), N-hydroxyphthalimide (NHPI), N-hydroxybenzotriazole (HOBt) and 1-hydroxy-7-azabenzotriazole (HOAt) lead to the corresponding oxygenated products in good to moderate yields. The application of this method has been demonstrated by transforming a few coupled products into synthetically useful intermediates and products.
- Siddaraju, Yogesh,Prabhu, Kandikere Ramaiah
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supporting information
p. 11651 - 11656
(2015/12/08)
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- BICYCLIC HETEROCYCLE DERIVATIVES AND USE THEREOF AS GPR119 MODULATORS
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The present invention relates to Bicyclic Heterocycle Derivatives of formula (I), compositions comprising a Bicyclic Heterocycle Derivative, and methods of using the Bicyclic Heterocycle Derivatives for treating or preventing obesity, diabetes, a metabolic disorder, a cardiovascular disease or a disorder related to the activity of GPR1 19 in a patient.
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Page/Page column 182
(2009/12/27)
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- Cerium-catalyzed α-hydroxylation reactions of α-cyclopropyl β-dicarbonyl compounds with molecular oxygen
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Three α-cyclopropyl β-dicarbonyl compounds have been used as probes for α-radicals as electrophilic reaction intermediates in a cerium-catalyzed α-hydroxylation reaction with molecular oxygen. Since the cyclopropyl group did not ring-open to products with a butenyl moiety, but was retained in the products, a localized unpaired electron at the α position can be excluded during the course of the reaction. The α-cyclopropyl- substituted substrates were prepared by aldol or Claisen reactions. Other substrates with α-methyl, α-isopropyl, and α-tert-butyl substituents were prepared and converted under the α-hydroxylation conditions in order to estimate steric influences on the yield of the reaction. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Christoffers, Jens,Kauf, Thomas,Werner, Thomas,Roessle, Michael
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p. 2601 - 2608
(2007/10/03)
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- ISOTHIAZOLE DIOXIDES AS CXC- AND CC- CHEMOKINE RECEPTOR LIGANDS
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Disclosed are novel compounds of the formula (IA): and the pharmaceutically acceptable salts and solvates thereof. D and E are different groups wherein one is N and the other is CR50. Examples of groups comprising Substituent A include heteroaryl, aryl, heterocycloalkyl, cycloalkyl, aryl, alkynyl, alkenyl, aminoalkyl, alkyl or amino. Examples of groups comprising Substituent B include aryl and heteroaryl. Also disclosed is a method of treating a chemokine mediated diseases, such as, cancer, angiogenisis, angiogenic ocular diseases, pulmonary diseases, multiple sclerosis, rheumatoid arthritis, osteoarthritis, stroke and cardiac reperfusion injury, pain (e.g., acute pain, acute and chronic inflammatory pain, and neuropathic pain) using a compound of formula IA.
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Page/Page column 282
(2010/02/13)
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- THIADIAZOLEDIOXIDES AND THIADIAZOLEOXIDES AS CXC- AND CC-CHEMOKINE RECEPTOR LIGANDS
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Disclosed are novel compounds of the formula (IA) and the pharmaceutically acceptable salts and solvates thereof. Examples of groups comprising Substituent A include heteroaryl, aryl, heterocycloalkyl, cycloalkyl, aryl, alkynyl, alkenyl, aminoalkyl, alkyl or amino. Examples of groups comprising Substituent B include aryl and heteroaryl. Also disclosed is a method of treating a chemokine mediated diseases, such as, cancer, angiogenisis, angiogenic ocular diseases, pulmonary diseases, multiple sclerosis, rheumatoid arthritis, osteoarthritis, stroke and cardiac reperfusion injury, acute pain, acute and chronic inflammatory pain, and neuropathic pain using a compound of formula (IA).
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Page 318-319
(2008/06/13)
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- 3,4-Di-substituted cyclobutene-1,2-diones as CXC-chemokine receptor ligands
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There are disclosed compounds of the formula or a pharmaceutically acceptable salt or solvate thereof which are useful for the treatment of chemokine-mediated diseases such as acute and chronic inflammatory disorders and cancer.
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- 3,4-Di-substituted cyclobutene-1,2-diones as CXC-chemokine receptor ligands
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There are disclosed compounds of the formula or a pharmaceutically acceptable salt or solvate thereof which are useful for the treatment of chemokine-mediated diseases such as acute and chronic inflammatory disorders and cancer.
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Page 176-177
(2008/06/13)
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- Substituted pyrazolyl benzenesulfonamides for use in veterinary therapies
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A method of using pyrazolyl benzenesulfonamide compounds in treating inflammation and inflammation-related disorders in companion animals is disclosed.
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- Substituted pyrazolyl benzenesulfonamides for the treatment of inflammation
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A class of pyrazolyl benzenesulfonamide compounds is described for use in treating inflammation and inflammation-related disorders. Compounds of particular interest are defined by Formula II: STR1 or a pharmaceutically-acceptable salt thereof.
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- α-(Phenylthio)cyclopropylation of carbonyl compounds: Preparation of α-cyclopropyl ketones
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α-Chloro-α-(phenylthio)cyclopropane and α-acetoxy-α-(phenylthio)cyclopropane were found to react with the silyl enol ethers of some ketones in the presence of Lewis acid in dichloromethane to provide α-(phenylthio)cyclopropyl ketones, which were subjected to reduction with Ra-Ni to give the corresponding α-cyclopropyl ketones.
- Pohmakotr, Manat,Thisayukta, Jirakorn
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p. 6759 - 6762
(2007/10/03)
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- REACTION OF HOMOALLYLIC COMPOUNDS OF TIN WITH ACYLATING AGENTS
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In the reaction of homoallylic organotin compounds with carboxylic acid anhydrides and chlorides in the presence of Lewis acids cyclopropyl methyl ketones are formed with α,β-unsaturated ketones and β-chloro ketones as impurities.The ratio of the reaction products depends on the temperature, the structure of the reagents, and the type of catalyst.
- Ivashchenko, N. B.,Polunin, E. V.,Kashin, A. N.
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p. 546 - 550
(2007/10/02)
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- MERCURY(II)-MEDIATED CYCLISATION OF HYDROPEROXYALKYLCYCLOPROPANES: A NEW ROUTE TO CYCLIC PEROXIDES
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Aldehydes, RCHO (R = Me, Et, iPr, and c-C6H11) have been converted via alkylation, cyclopropanation, oxidation, condensation with p-tosylhydrazine, reduction and perhydrolysis into 2-hydroperoxyalkylcyclopropanes RCH(OOH)CH2c-C3H5, and thence by cycloperoxymercuriation and reductive demercuriation into the corresponding 3-alkyl-5-ethyl-1,2-dioxolanes.
- Bloodworth, A. J.,Korkodilos, Despoina
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p. 6953 - 6956
(2007/10/02)
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- ETUDE DES PETITS CYCLES-XLIII. REACTIONS D'ADDITION SUR LES α-CYCLOPROPYLIDENE-CETONES ET SUR LES α-CYCLOPROPYLIDENE-ALDEHYDES
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α-Cyclopropylidene ketones and aldehydes show high reactivity towards 1,4-addition of methanol in acidic or basic medium, water and hydrochloric acid giving α-(1-methoxy cyclopropyl) ketones and aldehydes, α-(1-hydroxy cyclopropyl) ketones and α-(1-chloro cyclopropyl) ketones and aldehydes respectively.The reaction of α-cyclopropylidene-ketones with Grignard reagents gives mainly α-cyclopropyl ketones (the 1,4-addition product) besides α-cyclopropylidene carbinols (the 1,2-addition product).Addition of methyl-lithium and lithium dimethylcuprate lead to the expected 1,2- and 1,4-addition products,respectively.The comparison of the se results and those corresponding to α-isopropylidene-ketones confirms the higher tendency of α-cyclopropylidene-ketones to give 1,4-addition products; the measurement of polarographic reduction potentials confirms, in some cases, this difference.The reaction of HOBr (NBS, DMSO, H2O) with α-cyclopropylidene ketones produces α-hydroxy β-bromo ketones whereas the corresponding α-isopropylidene ketones give β-hydroxy α-bromo ketones.
- Lechevallier, A.,Huet, F.,Conia, J.M.
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p. 3317 - 3328
(2007/10/02)
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- β-STANNYLPROPIONALDEHYDE. A VERSATILE CYCLOPROPANE BUILDING-BLOCK
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Various functional group-substituted cyclopropanes were prepared in good yield starting from β-tributylstannylpropionaldehyde via homoallyl-stannanes or γ-hydroxypropylstannanes.
- Ueno, Yoshio,Ohta, Mitsuaki,Okawara, Makoto
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p. 2577 - 2580
(2007/10/02)
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- Reactivity of an α-Acyl-α-cyclopropyl-carbenium Ion: a Highly Stereoselective Cyclopropylmethyl-Cyclopropylmethyl Rearrangement
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The complete stereoselectivity in a cyclopropylmethyl-cyclopropylmethyl rearrangement which has been investigated is rationalized in terms of a highly preferred conformation of the transient α-acyl-α-cyclopropyl-carbenium ion.
- Pardo, Claude,Charpentier-Morize, Micheline
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p. 1037 - 1039
(2007/10/02)
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- ADDITION REACTIONS TO α-CYCLOPROPYLIDENE KETONES AND ALDEHYDES.
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α-Cyclopropylidene ketones show high reactivity towards 1,4-addition reactions.
- Huet, F.,Lechevallier, A.,Conia, J. M.
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p. 3585 - 3588
(2007/10/02)
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