- Electrooxidative Dearomatization to Spiroisoxazolines: Application to Total Synthesis of Xanthoisoxazoline B
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The synthesis of spiroisoxazoline molecules has been developed via anodic oxidative dearomatization of 4-methoxybenzyl oximes. The reaction is thought to proceed through 5-exo C?O bond-forming cyclization of oxime radicals with arenes on the basis of cycl
- Chen, Dengfeng,He, Tianyu,Jin, Yongcan,Huang, Shenlin
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supporting information
p. 286 - 290
(2021/11/13)
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- Copper-Catalyzed Aza-Sonogashira Cross-Coupling To Form Ynimines: Development and Application to the Synthesis of Heterocycles
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Nitrogen-substituted alkynes, such as ynamines and ynamides, are versatile synthetic building blocks. Ynimines bearing additional nucleophilic and electrophilic centers relative to ynamines and ynamides are expected to have high synthetic potential. However, their chemical reactivity remains unexplored owing mainly to the lack of synthetic accessibility. We report herein a versatile copper-catalyzed synthesis of ynimines from readily available O-acetyl ketoximes and terminal alkynes. A wide range of O-acetyl ketoximes derived from diaryl ketones, aryl alkyl ketones and dialkyl ketones underwent cross-coupling with a diverse set of terminal alkynes to afford the ynimines in good to excellent yields. An unprecedented [5+1] heteroannulation reaction exploiting the reactivity of the ynimine generated in situ was subsequently developed for the synthesis of medicinally important heterocycles, including isoquinolines, azaindoles, azabenzofurans, azabenzothiophenes and carbolines.
- Lavernhe, Rémi,Torres-Ochoa, Rubén O.,Wang, Qian,Zhu, Jieping
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supporting information
p. 24028 - 24033
(2021/10/07)
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- ASPARAGINE DERIVATIVES AND METHODS OF USE THEREOF
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The present invention relates to compounds of formulas (A) and (I), pharmaceutically acceptable salts thereof, and solvates of any of them, pharmaceutical compositions comprising them, methods of preparation thereof, intermediate compounds useful for the preparation thereof, and methods of treatment or prophylaxis of diseases, in particular cancer, such as colorectal cancer, using these. (A) (I)
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Paragraph 00733-00734
(2021/12/31)
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- Dynamic path bifurcation in the Beckmann reaction: Support from kinetic analyses
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The reactions of oximes to amides, known as the Beckmann rearrangement, may undergo fragmentation to form carbocations + nitriles when the migrating groups have reasonable stability as cations. The reactions of oxime sulfonates of 1-substituted-phenyl-2-propanone derivatives (7-X) and related substrates (8-X, 9a-X) in aqueous CH3CN gave both rearrangement products (amides) and fragmentation products (alcohols), the ratio of which depends on the system; the reactions of 7-X gave amides predominantly, whereas 9a-X yielded alcohols as the major product. The logk-logk plots between the systems gave excellent linear correlations with slopes of near unity. The results support the occurrence of path bifurcation after the rate-determining TS of the Beckmann rearrangement/fragmentation reaction, which has previously been proposed on the basis of molecular dynamics simulations. It was concluded that path-bifurcation phenomenon could be more common than thought and that a reactivity-selectivity argument based on the traditional TS theory may not always be applicable even to a well-known textbook organic reaction.
- Yamamoto, Yutaro,Hasegawa, Hiroto,Yamataka, Hiroshi
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experimental part
p. 4652 - 4660
(2011/07/29)
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- Solvents inducing oxidation of hydroxylamines
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Hydroxylamines gradually undergo oxidation to their oximes on being dissolved in organic solvent (e.g. methanol). This phenomenon was followed by 1H-NMR and liquid chromatography-mass spectrometry (LC-MS). The oxidation rate was estimated from
- Horiyama, Shizuyo,Suwa, Kiyoko,Yamaki, Masae,Kataoka, Hiromi,Katagi, Toyoshi,Takayama, Mitsuo,Takeuchi, Takae
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p. 996 - 1000
(2007/10/03)
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- Cathodic Reduction of 1-Nitroalkenes to Oximes and Primary Amines
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1-Nitroalkenes are reduced in high yields at -0.3 to -0.5 V (vs.SCE) at a mercury or graphite cathode to oximes.At higher cathodic reduction potentials (-1.1 V) primary amines are selectively obtained in fair yields.Nitroalkadienes are selectively reduced at the double bond conjugated with the nitro group to either the oxime or amine.Key Words: Electrochemistry / 1-Nitroalkenes, reduction of / Oximes / Amines
- Wessling, Michael,Schaefer, Hans J.
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p. 2303 - 2306
(2007/10/02)
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- REDUCTIVE CONVERSION OF NITRO ALKENES TO KETONES AND/OR OXIMES IN AN AQUEOUS HClO4-CH2Cl2-DIOXANE-(Pb) SYSTEM
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Electrochemical and chemical reduction of nitro alkenes in an aqueous HClO4-CH2Cl2-dioxane-(Pb) system afforded ketones and oximes in good yields, each of which can be obtained selectively by treating with either aqueous formaldehyde or hydroxylamine as a proper workup process, respectively.
- Torii, Sigeru,Tanaka, Hideo,Katoh, Tetsuo
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p. 607 - 610
(2007/10/02)
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- Alkylwanderungen bei Sextettumlagerungen
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The migration aptitude of alkyl groups in the Beckmann-, the Criegee-, and the isonitrile-nitrile rearrangements were investigated.The relative rearrangement rates of substituted benzyl groups are an expression of the charge on the migrating carbon at transition state.From the relative rates of migration of exo- and endo-2-norbornyl groups the geometrical changes at the migrating carbon is estimated.Finally, the different influence of α-branching in the migrating group is discussed for these and some other rearrangements.
- Langhals, Heinz,Range, Guenter,Wistuba, Eckehardt,Ruechardt, Christoph
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p. 3813 - 3830
(2007/10/02)
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