- Method for preparing intermediate of chiral vicinal diamine
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The invention discloses a method for preparing an intermediate of chiral vicinal diamine. The method comprises the following steps: adding a compound IV into a solvent, stirring the compound IV and the solvent in an ice water bath, adding an initiator into the obtained reaction system, adding a reducing agent into the reaction system in batches, heating the reaction system to 20-80 DEG C, and stirring the reaction system; and extracting the reaction system after the reaction is completed, drying the obtained organic phase, filtering the dried organic phase, and performing rotary drying to obtain a compound V that is the intermediate. The preparation method of the invention has the advantages of simplicity and mild reaction conditions, and can be widely applied to industrial production.
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Paragraph 0034; 0035; 0038
(2019/01/06)
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- Copper-catalyzed TEMPO oxidative cleavage of 1,3-diketones and β-keto esters for the synthesis of 1,2-diketones and α-keto esters
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A copper-catalyzed efficient and practical method has been developed for the synthesis of 1,2-diketones and α-keto esters. TEMPO was used as a radical initiator and scavenger, oxidizing the cleavage of α-methylene of 1,3-diketones and β-keto esters to form 1,2-diketones and α-keto esters. This method provided a general way for the formation of 1,2-dicarbonyl compounds.
- Zhou, Peng-Jun,Li, Cheng-Kun,Zhou, Shao-Fang,Shoberu, Adedamola,Zou, Jian-Ping
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p. 2629 - 2637
(2017/04/03)
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- Practical and theoretical aspects of Wacker oxidation of tolanophanes: Synthesis and characterization of novel diketonic cyclophanes
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Novel cyclophanes having 1,2-diketones 2a–c were synthesized by Wacker oxidation of the corresponding tolanophanes 1a–c having various alkyl chain lengths (n?=?2–4). Among them, tolanophane 1a with the shortest alkyl chain length (n?=?2) having more strained alkyne shows the lowest product selectivity even lower than that of acyclic analogues at various reaction temperatures. In contrast, the oxidation of tolanophane 1b (n?=?3) is clean with the highest activity and selectivity of 2b. Theoretical calculations confirm the experimental data. Based on ab initio calculations, the critical step of the reaction pathway is the interaction of oxygen atoms of 1 (in the absence of H2O) with Pd ion of intermediate [PdCl3(1)]? to give [PdCl2(1)] which keeps Pd ion close to the alkyne bond. This step is not observed computationally for 1a because the positions of the oxygen atoms are outside of its central part. This is in good agreement with almost no activity of 1a at room temperature to prove its rigid structure preventing the O…Pd interaction. Nevertheless, the alkyne…Pd interaction of 1b is not detected by NMR measurements which may be due to its too slow interaction at room temperature (35% after 24?h); however, this confirms ab initio calculation data that the preferred coordinating site is oxygen in the reaction pathway. In contrast, cyclic voltammetry measurements distinguish a different behaviour for the palladium complexation of 1. In general, it is found that the stereochemistry of tolanophanes rather than distortion of alkyne bond plays the critical role in the oxidation. The products are new and their structures were characterized.
- Darabi, Hossein Reza,Rastgar, Saeed,Khatamifar, Ehsan,Aghapoor, Kioumars,Sayahi, Hani,Firouzi, Rohoullah
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- NaBrO3/bmim[HSO4]: a versatile system for the selective oxidation of 1,2-diols, α-hydroxyketones, and alcohols
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Abstract: Sodium bromate with bmim[HSO4] has been found to be an excellent oxidizing agent in aqueous medium. NaBrO3:bmim[HSO4] oxidized 1,2-diols, α-hydroxyketones, and alcohols to the corresponding carbonyl compounds in excellent yields. This method offers advantages such as low cost reagents, aqueous reaction conditions, moderate temperatures and short reaction times and hence environmentally benign reaction. Moreover, the ionic liquid bmim[HSO4] could be recycled for at least three times without loss of significant activity. Graphical abstract: [Figure not available: see fulltext.]
- Khurana, Jitender M.,Lumb, Anshika,Chaudhary, Ankita
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p. 381 - 386
(2017/02/10)
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- Preparation method of 1,2-diketone derivative
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The invention discloses a preparation method of a 1,2-diketone derivative. The method comprises the step of enabling a raw material 1,3-diketone derivative to react with a cheap and easily obtained industrial product 2,2,6,6-tetramethyl-1-piperidinyloxy under the catalysis of copper so as to obtain the product 1,2-diketone derivative. According to the preparation method, the 1,3-diketone derivative is used as an initiator, and the raw material is easy to obtain and wide in variety; by utilizing the preparation method, the obtained product types are varied, can be directly used, and can be used for other further reactions; in addition, the reagent dosage in the reaction is less, the pollution is reduced, and the production cost is lowered; moreover the reaction conditions are mild, the reaction operation and the after-treatment process are simple, the reaction time is short, the yield is high, and the preparation method is suitable for industrial production.
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Paragraph 0028
(2016/10/08)
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- Highly efficient asymmetric hydrogenation of cyano-substituted acrylate esters for synthesis of chiral γ-lactams and amino acids
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A highly efficient and enantioselective synthesis of γ-lactams and γ-amino acids by Rh-catalyzed asymmetric hydrogenation has been developed. Using the Rh-(S,S)-f-spiroPhos complex, under mild conditions a wide range of 3-cyano acrylate esters including both E and Z-isomers and β-cyano-α-aryl-α,β-unsaturated ketones were first hydrogenated with excellent enantioselectivities (up to 98% ee) and high turnover numbers (TON up to 10 000).
- Kong, Duanyang,Li, Meina,Wang, Rui,Zi, Guofu,Hou, Guohua
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supporting information
p. 1216 - 1220
(2016/02/03)
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- Dendrimer-like core cross-linked micelle stabilized ultra-small gold nanoclusters as a robust catalyst for aerobic oxidation of α-hydroxy ketones in water
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As one of the most general and promising stabilizers, dendrimers have been widely used to prepare ultra-small gold nanoclusters. However, the complex synthesis of dendrimers hinders the further application of protected nanoclusters. Here we report a facile strategy to prepare an alternative material via core cross-linking of self-assembled micelles. The resulting dendrimer-like core cross-linked micelles (DCCMs) retain the main characteristics of dendrimers and avoid complex chemical synthesis. As expected, the DCCMs could easily encapsulate gold nanoparticles within their cores. The ultra-small clusters of Au5 were prepared without the participation of external reductants. Importantly, the DCCM stabilized noble gold clusters furnish excellent catalytic activity and perfect reusability for aerobic oxidation of α-hydroxy ketones in water. Only in open air the oxidation could be repeated up to 48 times with negligible turn-over frequency change. The total turnover number (TON) of the reaction reached unexpectedly >48 000, the highest TON for metal catalysed oxidation of hydroxy ketones so far. The further mechanism study hints that the carboxylic group of substrates might be involved in the catalytic process. The simple catalyst preparation, the environmentally benign reaction conditions, and the excellent catalytic performance and durability make the novel DCCM protected gold nanocluster a green catalyst.
- Yu, Yangyang,Lin, Chenlu,Li, Bing,Zhao, Pengxiang,Zhang, Shiyong
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p. 3647 - 3655
(2016/07/06)
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- A NOVEL QUINOXALINE COMPOUND FOR ULTRAVIOLET ABSORBERS
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PURPOSE: A novel quinoxaline compound, isomer thereof, precursor drug thereof, or pharmaceutically acceptable salt thereof is provided to absorb UVA and UVB. CONSTITUTION: A quinoxaline compound is denoted by chemical formula 1. An UV absorber or pharmaceutical or cosmetic composition for antiaging contains the quinoxaline compound, isomer thereof, precursor drug thereof, or pharmaceutically acceptable salt, hydrate, or solvate thereof as an active ingredient.
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Paragraph 0053-0054; 0059-0060
(2017/10/21)
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- Metal-Free [4+2] Annulation of Arylalkynes with tert-Butyl Nitrite through C(sp2)-H Oxidation to Assemble Benzo[e][1,2]oxazin-4-ones
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A metal-free radical-mediated [4+2] annulation of internal arylalkynes with tert-butyl nitrite (t-BuONO) is presented for the synthesis of benzo[e][1,2]oxazin-4-ones through the addition of t-BuONO across the C-C triple bond, hydration, isomerization and aromatic C(sp2)-H oxidation cascades. The 18O-labeling experiment shows that two oxygen atoms in the product system are from water.
- Yang, Xu-Heng,Song, Ren-Jie,Li, Jin-Heng
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supporting information
p. 3849 - 3856
(2016/01/25)
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- Synthesis of new chiral keto alcohols by baker's yeast
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Fourteen chiral α- and β-keto alcohols 2a-2r were synthesized by the asymmetric reduction of their corresponding diketones 1a-1r via baker's yeast. In addition, ten corresponding racemic α-keto alcohols were synthesized by the benzoin condensation of their corresponding aldehydes, which were used for the determination of the ee values through their chiral resolution on chiral HPLC. Amongst the 15 diketones, 1j and chiral α-keto alcohols 2i, 2j and chiral β-keto alcohol 2r are novel compounds. Six keto alcohols 2b, 2c, 2d, 2f, 2h and 2p were synthesized by baker's yeast for the first time. There are some studies in the literature where baker's yeast was applied to the diketones 1a, 1g, 1e, 1k and 1n under various conditions different to those reported herein. The yields and the ee values of these studies were not as high as ours. All of the keto alcohols synthesized were characterized by IR, NMR (1H and 13C), and MS. The relationship between the structure of the diketone and the yield, diastereoselectivity and enantiomeric excess is also discussed.
- Yildiz, Tuelay,Canta, Nurguel,Yusufoglu, Ayse
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p. 340 - 347
(2014/04/03)
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- Metal-free oxidation of α-hydroxy ketones to 1,2-diketones catalyzed by mesoporous carbon nitride with visible light
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As a photocatalyst, mesoporous carbon nitride (mpg-C3N 4) shows higher photocatalytic activities in organic synthesis. Herein we report an mpg-C3N4-catalyzed oxidation of α-hydroxy ketones to synthesize 1,2-diketones using visible light. This transformation represents a green and highly efficient synthetic route to synthesize 1,2-diketones for which catalytic approaches are scarce.
- Zheng, Zhishuo,Zhou, Xiaosong
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p. 1683 - 1686,4
(2020/08/31)
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- Synthesis and evaluation of quinoxaline derivatives as potential influenza NS1A protein inhibitors
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A library of quinoxaline derivatives were prepared to target non-structural protein 1 of influenza A (NS1A) as a means to develop anti-influenza drug leads. An in vitro fluorescence polarization assay demonstrated that these compounds disrupted the dsRNA-NS1A interaction to varying extents. Changes of substituent at positions 2, 3 and 6 on the quinoxaline ring led to variance in responses. The most active compounds (35 and 44) had IC50 values in the range of low micromolar concentration without exhibiting significant dsRNA intercalation. Compound 44 was able to inhibit influenza A/Udorn/72 virus growth.
- You, Lei,Cho, Eun Jeong,Leavitt, John,Ma, Li-Chung,Montelione, Gaetano T.,Anslyn, Eric V.,Krug, Robert M.,Ellington, Andrew,Robertus, Jon D.
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supporting information; scheme or table
p. 3007 - 3011
(2011/06/24)
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- Enantioselective aerobic oxidation of α-hydroxy-ketones catalyzed by oxidovanadium(V) methoxides bearing chiral, N-salicylidene- tert -butylglycinates
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Chiral oxidovanadium(V) methoxides prepared from 3,5-disubstituted-N- salicylidene-l-tert-butylglycines and vanadyl sulfate in air-saturated MeOH serve as highly enantioselective catalysts for asymmetric aerobic oxidations and kinetic resolution of alkyl, aryl, and heteroaryl α-hydroxy-ketones with differed α-substituents at ambient temperature in toluene or TBME (tert-butyl methyl ether). The best scenarios involve the use of complexes which bear the tridendate templates derived from 3,5-diphenyl- or 3-o-biphenyl-5-nitro-salicyaldehyde. The kinetic resolution selectivities of the aerobic oxidation process are in the range of 12 to >1000 based on the selectivity factors (krel).
- Chen, Chien-Tien,Kao, Jun-Qi,Salunke, Santosh B.,Lin, Ya-Hui
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supporting information; experimental part
p. 26 - 29
(2011/03/22)
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- Galactose oxidase model: Biomimetic enantiomer-differentiating oxidation of alcohols by a chiral copper complex
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An enantiopure analogue of galactose oxidase (GO) was synthesized from an easily and readily available source with a similar activity of GO's in primary alcohol oxidation and enantioselective catalysts for aerobic oxidative kinetic resolution (AORK) of racemic secondary alcohols. Enantiopure (R)-binam was treated with Cu(OTf)2 in toluene at room temperature for one hour to give a (R)-binam-Cu complex. It is found that enantiopure benzoin is an important intermediate in the synthesis of a potent anticancer agent and can been synthesized by enzymatic hydrolysis with benzaldehyde lyase (BAL). The S enantiomer of the racemate is oxidized faster to the corresponding benzil and the slow-reacting R enentiomer of benzoin is recovered in an enantiomerically enriched form. It is also observed that ortho substitution reduces the rate of reaction, while a reduced enentioselectivity is observed in case of ortho-substituted benzoin.
- Alamsetti, Santosh Kumar,Mannam, Sreedevi,Mutupandi, Pandi,Sekar, Govindasamy
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supporting information; experimental part
p. 1086 - 1090
(2009/10/23)
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- Hydrogen bonding makes a difference in the rhodium-catalyzed enantioselective hydrogenation using monodentate phosphoramidites
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A new generation of monodentate phosphoramidite ligands bearing a primary amine moiety was found to display comparable or better efficiency than bisphosphines in the Rh-catalyzed asymmetric hydrogenation of challenging substrates, such as (Z)-methyl α-ace
- Liu, Yan,Sandoval, Christian A.,Yamaguchi, Yoshiki,Zhang, Xue,Wang, Zheng,Kato, Koichi,Ding, Kuiling
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p. 14212 - 14213
(2008/02/09)
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- Electrochemical oxidation of benzoins to benzils in the presence of a catalytic amount of KI in basic media
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Various benzoins were transformed into the corresponding benzils via an electrochemical method. Although the strategy of oxidizing benzoins to the corresponding benzils is generally chosen depending on the nature of the aromatic moiety, the electrochemical technique reported herein allows oxidation that is widely applicable, and without the use of environmentally undesirable oxidants.
- Okimoto, Mitsuhiro,Takahashi, Yukio,Nagata, Yuji,Sasaki, Gaku,Numata, Kaori
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p. 705 - 707
(2007/10/03)
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- Samarium diiodide promoted formation of 1,2-diketones and 1-acylamido-2-substituted benzimidazoles from N-acylbenzotriazoles
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N-Acylbenzotriazoles, when treated with samarium diiodide in THF, undergo self-coupling reaction to afford 1,2-diketones in good to excellent yields; while when treated with samarium diiodide in CH3CN, they undergo ring-opening reaction to afford 1-acylamido-2-alkyl (or aryl) benzimidazoles in reasonable to good yields. A plausible mechanism was suggested.
- Wang, Xiaoxia,Zhang, Yongmin
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p. 4201 - 4207
(2007/10/03)
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- Formation of 1,2-diketones by samarium diiodide promoted reaction of N-acylbenzotriazoles
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Transformation of N-acylbenzotriazoles 1 into 1,2-diketones 2 in good to excellent yields has been realized by the use of samarium diiodide at room temperature.
- Wang, Xiaoxia,Zhang, Yongmin
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p. 5431 - 5433
(2007/10/03)
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- Studies on oxygen heterocycles part 2: Synthesis of 2-arylcoumaranones and 2-phenylbenzofuran
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The synthesis of 2-arylcoumaranones and 2-phenyllbenzofuran has been achieved in good yields under acid catalysed conditions from readily accessible and suitably substituted aryl α-diazo-arylmethyl ketones.
- Ghosh, Somnath,Banerjee, Indira,Baul, Susmita
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p. 11537 - 11546
(2007/10/03)
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- α-Keto Amides and 1,2-Diketones from N,N'-Dimethoxy-N,N'-dimethylethanediamide. A Synthetic and Mechanistic Investigation
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N,N'-Dimethoxy-N,N'-dimethylethanediamide (1), a 1,2-dicarbonyl synthon prepared from oxalyl chloride, undergoes nucleophilic displacements with Grignard reagents to provide α-keto amides 2-12 in 28-90percent yields.The synthon also undergoes double nucleophilic displacements with organolithium reagents to furnish symmetrical 1,2-diketones 15-23 in 15-84percent yields.A mechanism accounting for all the products from the reaction of 1 with nucleophiles has been proposed.Several control experiments were carried out to support the proposed mechanism.
- Sibi, Mukund P.,Marvin, Mali,Sharma, Rajiv
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p. 5016 - 5023
(2007/10/03)
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- N,N'-Dimethoxy-N,N'-dimethylethanediamide: A useful α-oxo-N-methoxy-N-methylamide and 1,2-diketone synthon
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N,N'-Dimethoxy-N,N'-dimethylethanediamide on treatment with one to two equivalents of alkyl, aryl, and benzyl Grignard reagents provide α-oxo-N-methoxy-N-methylamides in good to excellent yields and on reaction with excess aryllithiums furnish moderate to good yields of symmetrical 1,2-diarylketones.
- Sibi,Sharma,Paulson
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p. 1941 - 1944
(2007/10/02)
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- Colour and Conformation of Some Derivatives of Benzil in the Solid State. Crystal Structures of 2,2'-Dimethoxy-, 4,4'-Dimethoxy-, 4,4'-Diethoxy- and 4,4'-Dibenzyloxy-benzil
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The crystal structures of the colourless 2,2'-dimethoxybenzil (2) and 4,4'-diethoxybenzil (6), the yellow 4,4'-dimethoxybenzil (5), and the yellow polymorph of 4,4'-dibenzyloxybenzil (7) have been determined by single-crystal X-ray studies from diffractom
- Cannon, Jack R.,Patrick, Vincent A.,White, Allan H.
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p. 1631 - 1646
(2007/10/02)
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- An Unusual Reaction of a Phosphorane with Benzoins: Formation of 1,2-Dicarbonyl and 1,4-Dicarbonyl Compounds
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Benzoins (1a-e) on reaction with carbethoxymethylenetriphenylphosphorane (2) furnish hydroxy esters (3a-e) and butenolides (4a and 4e) along with the unusual products, benzils (5a-e) and ketoesters (6a-e) as major product.
- Ranade, A. C.,Mali, R. S.,Kurnawal, V. M.
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p. 514 - 517
(2007/10/02)
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- Mercury in Organic Chemistry. 26. Synthesis of Heterocycles via Intramolecular Solvomercuration of Aryl Acetylenes
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A number of ortho substituted aryl acetylenes, o-CH3XC6H4YCCR (X=O, S, CO2; Y=-, CO), have been observed to undergo facile intramolecular solvomercuration with mercuric acetate in acetic acid to afford the corresponding benzofuran, benzothiophene, isocoumarin, and chromone organomercuric chlorides, after aqueous sodium chloride workup.The aryl acetylenes m-XC6H4YCH2CCR (X=H, Y=O, R=CH3; X=CH3O, Y=CH2, R=n-C3H7) undergo similar cyclizations to yield mercurated 2H-1-benzopyrans and 1,2-dihydronaphthalenes.The mercuration and subsequent carbonylation of o-R1OC6H4CCR2 1=Si(t-Bu)Me2, R2=CH3; R1=CH3, R2=o-C6H4OCH3> has provided a new approach to the coumarin and coumestan ring systems.
- Larock, Richard C.,Harrison, L. Wayne
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p. 4218 - 4227
(2007/10/02)
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- Preparation and antiinflammatory activity of some nonacidic trisubstituted imidazoles
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A number of trisubstituted imidazoles were made and several found to be potent antiinflammatory agents when examined in the carrageenan rat paw edema test. The antiinflammatory activity of these compounds is retained in adrenalectomized rats. Unlike many previously reported antiinflammatory agents, these compounds are extremely weak acids pK[a] ≥ 11) and are therefore not ionized at physiological pH. One compound, 4,5 bis (4 methoxyphenyl) 2 trifluoromethylimidazole (flumizole), is more potent than indometacin in the rat paw edema test and, in contrast to some related compounds, does not cause photosensitization in mice.
- Lombardino,Wiseman
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p. 1182 - 1188
(2007/10/04)
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