- Copper-Catalyzed Annulation of Oxime Acetates with α-Amino Acid Ester Derivatives: Synthesis of 3-Sulfonamido/Imino 4-Pyrrolin-2-ones
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A copper-catalyzed annulation of oxime acetates and α-amino acid ester derivatives for the easy preparation of 4-pyrrolin-2-ones bearing a 3-amino group has been developed. This process features the oxidation of amines with oxime esters as the internal oxidant to produce the active 1,3-dinucleophilic and 1,2-dielectrophilic species concurrently. The subsequent nucleophilic cyclization realizes the efficient construction of 4-pyrrolin-2-one derivatives.
- Miao, Chun-Bao,Zheng, An-Qi,Zhou, Li-Jin,Lyu, Xinyu,Yang, Hai-Tao
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p. 3381 - 3385
(2020/04/21)
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- Copper-catalyzed synthesis of thiazol-2-yl ethers from oxime acetates and xanthates under redox-neutral conditions
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A novel copper-catalyzed annulation of oxime acetates and xanthates for the synthesis of thiazol-2-yl ethers with remarkable regioselectivity has been developed. Various oxime acetates, whether derived from aryl ketones or alkyl ketones, or natural product cores are suitable for this conversion. Unique dihydrothiazoles were also obtained when both reaction sites were methine. Mechanistic studies indicated that imino copper(iii) intermediates were involved. In addition, this protocol proceeded under redox-neutral conditions and did not require additives or ligands.
- Zhu, Zhongzhi,Tang, Xiaodong,Cen, Jinghe,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
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p. 3767 - 3770
(2018/04/17)
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- A new route to substituted furocoumarins via copper-catalyzed cyclization between 4-hydroxycoumarins and ketoximes
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A new route to substituted furocoumarins via copper-catalyzed cyclization between 4-hydroxycoumarins and ketoximes was developed. CuBr2 exhibited higher activity than other copper salts, affording the desired furocoumarins in high yields. The transformation proceeded readily in the absence of stoichiometric external oxidants. The significance of this synthetic strategy would be (1) the easily available starting materials; (2) low cost catalyst CuBr2; and (3) being without stoichiometric external oxidants. This protocol is complementary to previous approaches in the synthesis of substituted furocoumarins.
- To, Tuong A.,Vo, Yen H.,Nguyen, Anh T.,Phan, Anh N. Q.,Truong, Thanh,Phan, Nam T. S.
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p. 5086 - 5089
(2018/07/29)
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- Catalyst free synthesis of mono- and disubstituted pyrimidines from O-acyl oximes
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Transition-metal or iodine catalyzed transformations of O-acyl oximes to various N-heterocycles are well established. Herein, we report a catalyst free, oxime carboxylate based, three-component condensation method to access mono- and disubstituted pyrimidines. A broad range of substituted pyrimidines were prepared in moderate to excellent yields. Control experiments reveal that in situ generated formamidine is the key intermediate.
- Upare, Atul,Sathyanarayana, Pochampalli,Kore, Ranjith,Sharma, Komal,Bathula, Surendar Reddy
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p. 2430 - 2433
(2018/05/23)
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- Copper-catalyzed radical/radical cross-coupling of ketoxime carboxylates with 4-hydroxycoumarins: A novel synthesis of furo[3,2-c]-coumarins
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A novel and efficient strategy for the synthesis of furo[3,2-c]coumarins has been developed via copper-catalyzed radical/radical cross-coupling of ketoxime carboxylates with 4-hydroxycoumarins. This redox-neutral reaction allows smooth and selective synthesis of 2-substituted, 3-substituted, 2,3-disubstituted and 2,3-fused polycyclic furo[3,2-c]coumarins.
- He, Mingchuang,Yan, Zhaohua,Wang, Wangyang,Zhu, Fuyuan,Lin, Sen
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p. 3706 - 3712
(2018/09/12)
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- Improvement of liquid crystal alignment using novel photo-activators
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Photo-activator is a kind of additive that can improve the anchoring energy by attacking some of the bonds of polyimide (PI). Photo-activators were synthesized from the reaction of cyclohexanone oxime with three different anhydrides, respectively. Each ac
- Lee, In-Hye,Shin, Dong-Myung
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p. 7207 - 7210
(2018/06/29)
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- Iron-Catalyzed Synthesis of 2H-Imidazoles from Oxime Acetates and Vinyl Azides under Redox-Neutral Conditions
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A novel and versatile method for the synthesis of 2H-imidazoles via iron-catalyzed [3 + 2] annulation from readily available oxime acetates with vinyl azides has been developed. This denitrogenative process involved N-O/N-N bond cleavages and two C-N bond formations to furnish 2,4-substituted 2H-imidazoles. This protocol was performed under mild reaction conditions and needed no additives or ligands. Furthermore, this is a green reaction involving oxime acetate as internal oxidant, acetic acid, and nitrogen as byproducts.
- Zhu, Zhongzhi,Tang, Xiaodong,Li, Jianxiao,Li, Xianwei,Wu, Wanqing,Deng, Guohua,Jiang, Huanfeng
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p. 1370 - 1373
(2017/03/23)
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- Divergent Iron-Catalyzed Coupling of O-Acyloximes with Silyl Enol Ethers
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An iron-catalyzed coupling reaction of O-acyloximes and O-benzoyl amidoximes with silyl enol ethers is reported. The protocol provides access to functionalized pyrroles, 1,6-ketonitriles, pyrrolines and imidazolines via carbon-centered radicals generated from an initially formed iminyl radical. The intramolecular cyclization and ring-opening processes of the iminyl radical take place preferentially over reactions that proceed through a 1,3-hydrogen transfer, providing insights into iron-catalyzed reactions with oxime derivatives. The cheap and environmentally friendly iron catalyst, the broad substrate scope and the functional group compatibility make this protocol useful for synthesis of valuable nitrogen-containing products.
- Yang, Hai-Bin,Selander, Nicklas
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supporting information
p. 1779 - 1783
(2017/02/15)
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- Copper-catalyzed homocoupling of ketoxime carboxylates for synthesis of symmetrical pyrroles
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A novel and efficient copper-catalyzed homocoupling of ketoxime carboxylates has been developed for the synthesis of symmetrical pyrroles. This reaction tolerates a wide range of functional groups and provides a synthetically useful process to synthesize
- Ran, Longfei,Ren, Zhi-Hui,Wang, Yao-Yu,Guan, Zheng-Hui
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supporting information
p. 112 - 115
(2014/01/06)
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- Efficient microwave-assisted synthesis of oximes from acetohydroxamic acid and carbonyl compounds using BF3·OEt2 as the catalyst
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An efficient synthesis of oximes by reaction of carbonyls with acetohydroxamic acid using BF3·OEt2 as a catalyst is described.
- Sridhar, Madabhushi,Narsaiah, Chinthala,Raveendra, Jillella,Kondal Reddy, Godala,Kishore Kumar Reddy, Mallu,China Ramanaiah, Beeram
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scheme or table
p. 4701 - 4704
(2011/09/20)
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- Preparative synthesis of cyclohexanone oxime esters
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Preparative procedures have been developed for the synthesis of cyclohexanone oxime esters by acylation of cyclohexanone oxime with carboxylic acid anhydrides in the presence of perchloric acid or with carboxylic acid chlorides in the presence of pyridine
- Dikusar,Zhukovskaya
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experimental part
p. 1389 - 1391
(2009/09/06)
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- Processes for producing alpha -cyanohydrin esters and alpha -hydroxy acids
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In the presence of a metal catalyst such as a samarium compound, an enol ester compound shown by the formula (1) is reacted with a carbonyl compound shown by the formula (3) and a cyanogenation agent to produce an alpha -cyanohydrin ester shown by the formula (4): wherein R1, R7, and R8 are the same or different from each other, each representing a non-reactive atom or a non-reactive organic group; R2, R3, and R4 are the same or different from each other, each representing a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. By hydrolyzing the obtained compound, the corresponding alpha -hydroxy acid or a salt thereof can be obtained. According to the above processes, an alpha -cyanohydrin ester and an alpha -hydroxy acid can be obtained in high yields.
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- Processes for producing alpha -aminonitrile derivatives and alpha -amino acids
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In the presence of a metal catalyst such as a samarium compound, an oxime ester compound shown by the formula (1): wherein R1, R2, and R3 are the same or different from each other, and each represents a non-reactive atom or a non-reactive organic group; and R2 and R3, together with the adjacent carbon atom, may bond together to form a ring is reacted with a cyanogenation agent such as an alpha -cyanohydrin compound (e.g., acetone cyanohydrin) to form an alpha -aminonitrile derivative. By hydrolyzing the alpha -aminonitrile derivative, the corresponding alpha -amino acid or a salt thereof can be obtained. According to the above processes, an alpha -aminonitrile derivative and an alpha -amino acid can be obtained in high yields.
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- Reduction of O-acyl oximes with sodium borohydride/iodine system
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O-acyl derivatives of aldoximes and ketoximes are reduced in good yields to the corresponding amines with sodium borohydride-iodine system.
- Barbry,Champagne
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p. 3503 - 3507
(2007/10/03)
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- Acylation and alkoxycarbonylation of oximes through an enzymatic oximolysis reaction
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Ketone or benzaldehyde O-acyloximes and O-(tert-butoxycarbonyl)oximes can be prepared by reaction of oximes with vinyl esters and di-tert-butyl dicarbonate, respectively, using lipases as biocatalysts.
- Menendez,Gotor
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- (Trimethylsilyl)ethoxyacetylene. An Effective Reagent for Mild Dehydrative Condensation of Carboxylic Acids and H-Acidic Materials
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(Trimethylsilyl)ethoxyacetylene, a stable and easy to handle dehydrating reagent, is quite effective for the title condensation to prepare ester-, lactone-, lactam-, and peptide-linkages under mild conditions.
- Kita, Yasuyuki,Akai, Shuji,Yamamoto, Miki,Taniguchi, Miyako,Tamura, Yasumitsu
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p. 334 - 337
(2007/10/02)
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- A New Synthesis of Oxime Derivatives from Carbonyl Compounds and N,O-Bis(trimethylsilyl)hydroxylamine
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Reaction of a series of aldehydes and ketones with the potassium salt of N,O-bis(trimethylsilyl)hydroxylamine (2) gave high yields of the corresponding oximate anion 5.This anion, formed in a Peterson-type reaction, could be protonated to the oxime 7 or trapped in situ with a variety of electrophiles to give O-substituted oxime derivatives.
- Hoffman, Robert V.,Buntain, Gregory A.
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p. 831 - 833
(2007/10/02)
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