- N-Heterocycle-Stabilized Iodanes: From Structure to Reactivity
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Pseudocyclic aryl-λ3-iodanes are superior reagents for a variety of oxidative transformations due to a well-balanced relation between stability, solubility and reactivity. Their properties are substantially influenced by a dative interaction between a Lewis base, in general the oxygen atom of a carboxylic acid or an amide, and the central hypervalent iodine atom. This work presents the first systematic investigation of pseudocyclic N-heterocycle-stabilized iodanes (NHIs). The synthesis of these throughout shelf-stable solids is robust and can be achieved on a large scale. Their reactivity is highly tunable, depending on the stabilizing heterocycle. Solid state structures of selected derivatives are reported and their reactivity in a model oxygen transfer reaction is compared. Further derivatization reactions to N-heterocycle-stabilized pseudocyclic diaryliodonium salts and cyclic iodoso species are presented as well.
- Boelke, Andreas,Lork, Enno,Nachtsheim, Boris J.
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p. 18653 - 18657
(2018/11/23)
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- Method for preparing axitinib and intermediates thereof
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The invention discloses a method for preparing axitinib and intermediates thereof. A chemical name of the axitinib is N-methyl-2-[(3-(1E-2-(pyridine-2-yl)ethylene)-1H-indazole-6-yl)sulfur]benzamide, and a chemical formula of the axitinib is C22H18N4OS. The preparation process disclosed by the invention is simple in process, readily available in raw materials, economic, environmentally friendly, high in product yield and product purity, contributes to realizing industrialization, reduces the production cost and is suitable for mass production. The provided novel intermediates and the preparation method thereof have significance on the economic technology of the axitinib.
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- Copper-Catalyzed C(sp3)-S Bond and C(sp2)-S Bond Cross-Coupling of 2-(2-Iodobenzoyl) Substituted or 2-(2-Iodobenzyl) Substituted 1,2,3,4-Tetrahydroisoquinolines with Potassium Sulfide: Synthesis of Isoquinoline-Fused 1,3-Benzothiazine Scaffolds
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The sulfuration reaction of 2-(2-iodobenzoyl) substituted, or 2-(2-iodobenzyl) substituted 1,2,3,4-tetrahydroisoquinolines with potassium sulfide proceeded in the presence of copper catalysts to give tetrahydroisoquinoline-fused 1,3-benzothiazine scaffolds in moderate to appropriate yields. This protocol provided an efficient and simple strategy to construct the corresponding benzothiazine derivatives via formation of C(sp3)-S bond and C(sp2)-S bond, which the C-S bonds formed via different routes in this reaction (traditional cross-coupling reaction via the cleavage of C-I bond and oxidative cross-coupling reaction via C(sp3)-H bond functionalization).
- Dang, Pan,Zheng, Zhilei,Liang, Yun
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p. 2263 - 2268
(2017/02/26)
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- Synthesis of isocoumarins via silver(I)-mediated annulation of enol esters
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Silver-mediated annulation of 2-iodo enol esters leading to 4- and 3,4-substituted isocoumarins was accomplished selectively at room temperature. Coupling of 2-iodo benzoic acids with enolates that were produced in situ from the simple esters was also performed to produce isocoumarins under analogous reaction conditions. Owing to the mildness of the current protocol, 4-acyl 3-substituted isocoumarins were efficiently produced without any deacylation.
- Panda, Niranjan,Mishra, Priyadarshini,Mattan, Irshad
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p. 1047 - 1056
(2016/02/19)
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- Palladium-catalyzed annulation reactions of methyl o-halobenzoates with azabicyclic alkenes: A general protocol for the construction of benzo[c]phenanthridine derivatives
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The annulation reaction of methyl o-halobenzoates with azabicyclic alkenes proceeds efficiently to give the corresponding benzo[c]phenanthridine derivatives in good to excellent yields using a developed base-free methodology based on our preliminary studies. Thirty-seven application examples validate the compatibility of the present strategy with different groups, particularly with the electron-deficient ones, that are difficult to access using other traditional methods. In addition, annulation reactions with non-symmetric azabicyclic alkenes are achieved in high regioselectivity.
- Guo, Cui,Huang, Kanglun,Wang, Bo,Xie, Longguang,Xu, Xiaohua
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p. 17271 - 17280
(2013/09/24)
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- Candida tenuis xylose reductase catalysed reduction of acetophenones: The effect of ring-substituents on catalytic efficiency
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The catalytic efficiencies of Candida tenuis xylose reductase catalysed reductions of mono-substituted acetophenones are in reasonable correlation with the σ-Hammett coefficients of the substituted phenyl groups. Variations of the substrate transformation rates are hence mainly caused by mesomeric and inductive effects of the substituents, while differences in substrate binding have a secondary relevance. Some substrate 1H NMR chemical shifts and carbonyl IR absorption bands are in reasonable accordance with the catalytic activities and allow the estimation of the transformation rates with good accuracy. The resulting substituted (S)-1-phenyl ethanols are generated in very high enantiomeric excess.
- Vogl, Michael,Kratzer, Regina,Nidetzky, Bernd,Brecker, Lothar
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p. 5863 - 5870
(2011/09/30)
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- Palladium-catalysed heteroannulation with terminal alkynes: A highly regio- and stereoselective synthesis of (Z)-3-aryl(alkyl)idene isoindolin-1- ones
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A highly regio- and stereoselective method for the synthesis of (Z)-3- aryl(alkyl)idene isoindolin-1-ones through palladium-copper catalysis is described. 2-Iodobenzamide 1 and its substituted derivatives 2-10 were reacted with terminal alkynes 11-19 in the presence of (PPh3)2PdCl2, CuI, and Et3N in DMF mostly at 80°C for 16 h to yield the 2-alkynyl substituted benzamides 20-38, 40-45, 77 which could then be cyclised with NaOEt in EtOH to the 3-aryl(alkyl)idene isoindolin-1-ones 46-49, 51, 53-55, 57, 59-71, 73 and 75. In certain cases, the isoindolin-1-ones 50, 52, 56 and 58 could be directly obtained by the palladium-catalysed reactions. (C) 2000 Elsevier Science Ltd.
- Kundu, Nitya G.,Khan, M. Wahab
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p. 4777 - 4792
(2007/10/03)
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- Fungicides for the control of take-all disease of plants
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A method of controlling Take-All disease of plants by applying a fungicide of the formula STR1 wherein Z1 and Z2 are C and are part of an aromatic ring which is benzothiophene; and A is selected from --C(X)-amine wherein the amine is an unsubstituted, monosubstituted or disubstituted amino radical, --C(O)--SR3, --NH--C(X)R4, and --C(=NR3)--XR7 ; B is --Wm --Q(R2)3 or selected from O-tolyl, 1-naphthyl, 2-naphthyl, and 9-phenanthryl, each optionally substituted with halogen or R4 ; Q is C, Si, Ge, or Sn; W is --C(R3)p H(2-p) --; or when Q is C, W is selected from --C(R3)p H(2-p), --N(R3)m H(1-m)--, --S(O)p--, and --O--; X is 0 or S; n is 0, 1, 2, or 3; m is 0 or 1; p is 0, 1, or 2; each R and R2 is independently defined herein; R3 is C1 -C4 alkyl; R4 is C1 -C4 alkyl, haloalkyl, alkoxy, alkylthio, alkylamino, or dialkylamino; and R7 is C1 -C4 alkyl, haloalkyl, or phenyl, optionally substituted with halo, nitro, or R4 ; or an agronomic salt thereof.
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- Oxidation during reductive cyclisations using Bu3SnH
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Reductive cyclisations using Bu3SnH include an "oxidation" step if the removal of an acidic proton from the intermediate cyclised radical, by Bu3SnH acting as a base, is favourable. A "pseudo" SRN1 mechanism is proposed.
- Bowman, W. Russell,Heaney, Harry,Jordan, Benjamin M.
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p. 10119 - 10128
(2007/10/02)
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