- Highly enantioselective intermolecular hydroamination of allylic amines with chiral aldehydes as tethering catalysts
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Chirally LinkedIn: Chiral aldehydes are effective tethering catalysts for enantioselective intermolecular hydroamination, which provides access to vicinal diamine motifs in good yields and excellent enantioselectivities (see scheme). This work highlights simple chiral α-oxygenated aldehydes as effective organocatalysts capable of efficiently inducing asymmetry through transient intramolecularity. Copyright
- MacDonald, Melissa J.,Hesp, Colin R.,Schipper, Derek J.,Pesant, Marc,Beauchemin, André M.
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supporting information
p. 2597 - 2601
(2013/03/14)
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- Cycloaddition of nitrones with arynes generated from benzobisoxadisilole or 2,3-naphthoxadisilole
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1,3-Dipolar cycloaddition of nitrones with arynes generated in situ from benzobisoxadisilole or 2,3-naphthoxadisilole afforded the oxadisilole fused benzo[d]isoxazoline or the naphtho[2,3-d]isoxazoline derivatives at room temperature in good yields.
- Wu, Kaicheng,Chen, Yali,Lin, Yibei,Cao, Weiguo,Zhang, Min,Chen, Jie,Lee, Albert W.M.
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experimental part
p. 578 - 582
(2010/09/05)
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- A novel one-pot reductive amination of aldehydes and ketones with lithium perchlorate and zirconium borohydride-piperazine complexes
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A novel, one-pot reductive mono-alkylation method of amines (primary and secondary), 1,2-phenylenediamine, O-trimethylsilylhydroxylamine, and N,N-dimethylhydrazine was developed using LiClO4 (5 mol %) as a source for in situ generation of imine
- Heydari, Akbar,Khaksar, Samad,Esfandyari, Maryam,Tajbakhsh, Mahmoud
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p. 3363 - 3366
(2007/10/03)
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- Phase-transfer catalysis for the synthesis of hydroxylamines from oximes using benzyltriethylammonium borohydride in methanol and under solid-phase conditions
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Effective phase-transfer catalysis methodologies for the reduction of oximes to hydroxylamines by a selective and versatile reducing agent, benzyltriethylammonium borohydride (BTEABH), in methanol and under solid-phase conditions are presented.
- Gopalakrishnan, Mannathusamy,Anandabaskaran, Thirunavukkarasu,Sureshkumar, Purusothaman,Thanusu, Jayaraman,Kumaran, Arumugam K.,Kanagarajan, Vijayakumar
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- Synthesis and tyrosinase inhibitory activity of novel N-hydroxybenzyl-N-nitrosohydroxylamines
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Several novel N-substituted N-nitrosohydroxylamines were synthesized. They all inhibited mushroom tyrosinase, but the type of inhibition was different depending on the substituent. Some N-(mono- or dihydroxybenzyl)-N-nitrosohydroxylamines exhibited uncompetitive inhibition with respect to L-dopa. Among them, compound 6 was also a competitive inhibitor with respect to oxygen. This observation suggests that another interaction by the meta- or para-hydroxyl group might stabilize the binding of the inhibitor to the enzyme through the oxygen binding site.
- Shiino, Mitsuhiro,Watanabe, Yumi,Umezawa, Kazuo
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p. 129 - 135
(2007/10/03)
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- Solvolysis of substituted benzyl azoxyarenesulfonates: Characterisation of the transition state and the selectivity of benzylic intermediates in 50% aqueous 2,2,2-trifluoroethanol
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Thirteen substituted benzyl azoxyarenesulfonates have been prepared and rate constants for solvolysis of twelve have been measured in 50% (v/v) aqueous 2,2,2-trifluoroethanol over a range of temperatures from which activation parameters and rate constants at 25°C have been determined. A six-point Hammett correlation for substituents in the benzylic electrofuge, with azoxytoluene-p-sulfonate as the common nucleofuge, gives ρ(σ+) = -3.27. With 4-methylbenzyl as a common electrofuge, four substituents in the azoxybenzenesulfonate nucleofuge give ρ(σ) = 1.07. Comparison with model reactions indicates a synchronous concerted rate-limiting fragmentation for these substrates. With the less reactive 3-chlorobenzyl as electrofuge, ρ for substituents in the nucleofuge is only ca. 0.7 which indicates a lower degree of charge development in the arenesulfonate in the transition state for these reactions. Product analyses have been carried out for compounds of high, intermediate, and low reactivity. These indicate a reactivity-selectivity relationship for capture of the substituted benzylic electrophiles by water and 2,2,2-trifluoroethanol. Substituted benzaldehydes are formed from the less reactive substrates, indicating trapping of the first-formed benzylic carbenium ion by nitrous oxide and subsequent elimination of nitrogen and a proton; but yields are low and decrease as the substituted benzyl cation becomes increasingly stable.
- Gordon,Maskill
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p. 2059 - 2062
(2007/10/03)
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- New NO donors with antithrombotic and vasodilating activities, Part 29. N-(1-cyanocyclohexyl)-C-phenylnitrones and glyoxaldinitrones.
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Six N-(1-cyanocyclohexyl)-C-phenylnitrones 4a-f (4b-f for the first time) and 22 glyoxaldinitrones 7a-v were prepared and tested for antithrombotic (p.o. administration to rats, 60 mg/kg) effects. Both classes of compounds exhibit considerable antithrombo
- Camehn,Rehse
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p. 130 - 134
(2007/10/03)
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