- Preparation method of benzyloxyamine hydrochloride
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The invention discloses a preparation method of benzyloxyamine hydrochloride. The preparation method comprises the following steps: (1) dispersing ketoxime 2 and alkali metal hydroxide into a mixed solvent of dimethylacetamide and water at the temperature of 50-55 DEG C and the stirring speed of 100-120 rpm; (2) dropwise adding a benzyl halide compound 1 into a dispersion body obtained in the step (1), reacting for 130-140 minutes at the temperature of 60-65 DEG C after dropwise adding is completed, then cooling to room temperature, adding water, extracting by using normal hexane, and distilling an organic phase under reduced pressure to obtain a product 3; and (3) adding the product 3 obtained in the step (2) into a mixed solution of methanol and a hydrochloric acid solution with the mass concentration of 38% , reacting for 200-220 minutes at the temperature of 35-40 DEG C and at the stirring speed of 80-100 rpm, distilling under reduced pressure until a solid is separated out, cooling to room temperature, washing the solid with petroleum ether, and drying to obtain the target product 4-benzyloxyamine hydrochloride. According to the preparation method, the total yield can reach 95% or above, and the product purity can reach 99% or above.
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Paragraph 0035-0039
(2021/04/14)
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- Metal-free, redox-neutral, site-selective access to heteroarylamine via direct radical?radical cross-coupling powered by visible light photocatalysis
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Transition-metal-catalyzed C?N bond-forming reactions have emerged as fundamental and powerful tools to construct arylamines, a common structure found in drug agents, natural products, and fine chemicals. Reported herein is an alternative access to heteroarylamine via radical?radical cross-coupling pathway, powered by visible light catalysis without any aid of external oxidant and reductant. Only by visible light irradiation of a photocatalyst, such as a metal-free photocatalyst, does the cascade single-electron transfer event for amines and heteroaryl nitriles occur, demonstrated by steady-state and transient spectroscopic studies, resulting in an amine radical cation and aryl radical anion in situ for C?N bond formation. The metal-free and redox economic nature, high efficiency, and site-selectivity of C?N cross-coupling of a range of available amines, hydroxylamines, and hydrazines with heteroaryl nitriles make this protocol promising in both academic and industrial settings.
- Zhou, Chao,Lei, Tao,Wei, Xiang-Zhu,Ye, Chen,Liu, Zan,Chen, Bin,Tung, Chen-Ho,Wu, Li-Zhu
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supporting information
p. 16805 - 16813
(2020/11/09)
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- Direct ortho -C-H functionalization of aromatic alcohols masked by acetone oxime ether via exo -palladacycle
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A simple and practical exo-oxime ether auxilixary for ortho-C-H functionalization of aromatic alcohols has been developed. Selective olefination of aromatic alcohols were first achieved via a six- or seven-membered exo-acetone oxime ether palladacycle with broad substrate scope. In addition, the crystal of the exo-palladacycle intermediate was obtained for the first time, and the application of this method in total synthesis of 3-deoxyisoochracinic acid was accomplished via a novel retro-synthetic disconnection approach, thus demonstrating the utility of this transformation.
- Guo, Kun,Chen, Xiaolan,Guan, Mingyu,Zhao, Yingsheng
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supporting information
p. 1802 - 1805
(2015/04/14)
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- Metal-free artificial nucleases based on simple oxime and hydroxylamine scaffolds
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Hydrolysis of DNA is of increasing importance in biotechnology and medicine. In this Letter, we present the DNA-cleavage potential of metal-free hydroxylamines and oximes as new members of nucleic acid cleavage agents.
- Fernandes, Luciano,Fischer, Franciele L.,Ribeiro, Carolina W.,Silveira, Gustavo P.,Sa, Marcus M.,Nome, Faruk,Terenzi, Hernan
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supporting information; experimental part
p. 4499 - 4502
(2009/04/08)
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- Thermal decomposition of O-benzyl ketoximes; role of reverse radical disproportionation
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Thermolyses of seven dialkyl, two alkyl-aryl and two diaryl O-benzyl ketoxime ethers, R1R2C=NOCH2Ph, have been examined in three hydrogen donor solvents: tetralin, 9,10-dihydrophenanthrene, and 9,10-dihydroanthracene. All the oxime ethers gave the products expected from homolytic scission of both the O-C bond (viz., R1R2C=NOH and PhCH3) and N-O bond (viz., R1R2C=NH and PhCH2OH). The yields of these products depended on which solvent was used and the rates of decomposition of the O-benzyl oxime ethers were greater in 9,10-dihydrophenanthrene and 9,10-dihydroanthracene than in tetralin. These results indicated that a reverse radical disproportionation reaction in which a hydrogen atom was transferred from the solvent to the oxime ether, followed by β-scission of the resultant aminoalkyl radical, must be important in the latter two solvents. Benzaldehyde was found to be an additional product from thermolyses conducted in tetralin. This, and other evidence, indicated that another induced decomposition mode involving abstraction of a benzylic hydrogen atom, followed by β-scission of the resulting benzyl radical, became important for some substrates. Participation by minor amounts of enamine tautomers of the oxime ethers was shown to be negligible by comparison of thermolysis data for the O-benzyloxime of bicyclo[3.3.1]nonan-9-one, which cannot give an enamine tautomer, with that of the O-benzyloxime of cyclohexanone.
- Blake, Jessie A.,Ingold, Keith U.,Lin, Shuqiong,Mulder, Peter,Pratt, Derek A.,Sheeller, Brad,Walton, John C.
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p. 415 - 420
(2007/10/03)
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- N-nitroso-N,O-dialkylhydroxylamines: Preparation, structure, and mechanism of the hydronium ion catalysed solvolytic nitrous oxide extrusion reaction
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Eleven N-nitroso-N,O-dialkylhydroxylamines, RN(NO)OR′, have been prepared and the mechanisms of their hydronium ion catalysed solvolyses in aqueous solution which liberate nitrous oxide have been investigated. All reactions are first-order in substrate and first-order in hydronium ion, and the second-order rate constants at 25°C vary over a range of less than 140 in spite of considerable variation in substrate structure (R ranges from methyl to 4-methoxybenzyl to 2-adamantyl, for example) and changes in solvent composition (water with up to 50% methanol or 66% acetonitrile). Enthalpies and entropies of activation are qualitatively similar throughout the range (ΔH?= 72-93 kJ mol-1 and ΔS? = -19 to -57 J K-1 mol-1) which, with the product analyses, are accommodated by a mechanism involving pre-equilibrium protonation of the substrates followed by rate-limiting dissociation to give RN2O+ and HOR′. The oxodiazonium ion intermediate, RN2O+, then dissociates further to give the carbenium ion intermediate, R+, or suffers direct nucleophilic displacement of N2O by solvent (the external nucleophile) or by R′OH (the internal nucleophile liberated in the initial fragmentation). The carbenium ion, R+ (if formed), suffers nucleophilic capture either by solvent or by R′OH. When acetonitrile is the co-solvent (rather than methanol) for the N-(2-adamantyl) substrate 3g, the product of the Ritter reaction, 2-acetamidoadamantane, is detected. These nitrous oxide liberating reactions are compared with the nitric oxide liberating reactions of related N-nitrosohydroxylamines, and the origin of the difference between them is identified. The N(1)-nitroso group in the N,O-dibenzyl compound 3c is shown by X-ray crystallography to be essentially coplanar with the C and O atoms also bonded to N(1).
- Bhat, J. Ishwara,Clegg, William,Maskill, Howard,Elsegood, Mark R.J.,Menneer, Iain D.,Miatt, Peter C.
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p. 1435 - 1446
(2007/10/03)
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- ADDITION OF ARYLLITHIUM COMPOUNDS TO OXIME ETHERS
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Addition of non-stabilized organolithium reagents to O-alkyl aldoximes in the presence of boron trifluoride etherate gives rise to O-alkyl hydroxylamines.The Z oxime isomer preferentially reacts under these reaction conditions.
- Rodriques, Karen E.,Basha, Anwer,Summers, James B.,Brooks, Dee W.
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p. 3455 - 3458
(2007/10/02)
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- THE CHEMISTRY OF DRUGS. III. ACID HYDROLYSIS OF ANTIMALARIAL 5-ALKOXY-6,6-DIMETHYL-5,6-DIHYDRO-S-TRIAZINES
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5-Alkoxy-6,6-dimethyl-5,6-dihydro-s-triazines undergo a fragmentation reaction in refluxing 1N HCl.The hydrolytic degradation of the antimalarial WR 99210 belonging to this class of compound was investigated.
- Bajwa, Balbir S.,Acton, Nancy,Brossi, Arnold
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p. 839 - 843
(2007/10/02)
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- ONE-STEP SYNTHESIS OF DIAZIRINES FROM O-TOSYL KETOXIMES AND ALKOXYAMINES
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The reaction of O-tosyloximes of acetone, hexafluoroacetone, and mesoxalic acid esters with alkoxyamines leads to the corresponding diazirines, while the reaction of benzophenone O-tosyloxime with methoxyamine gives only benzophenone O-methyloxime.O-Esters of acetoxime were isolated along with 3,3-dimethylazirine also in the reaction of O-tosylacetoxime with alkoxyamines.Nucleophilic attack of alkoxyamines on O-tosyloximes of mesoxalates is realized at the carbon atom of not only the C=O bond but also at the carbon atom of the C=O bond, and the latter leads to fragmentation of the O-tosyloxime to give N-alkoxycarbamates, a cyanocarbonate ester, and p-toluenesulfonic acid.In the presence of triethylamine, which blocks the C=N bond, the reaction of mesoxalate O-tosyloxime proceeds only via the fragmentation pathway.The mechanism of the formation of diazirines in the reaction of O-tosylketoximes with alkoxyamines is discussed.
- Shustov, G. V.,Tavakalyan, N. B.,Pleshkova, A. P.,Kostyanovskii, R. G.
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p. 600 - 605
(2007/10/02)
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