- A practical synthesis of α-bromo/iodo/chloroketones from olefins under visible-light irradiation conditions
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A practical synthesis of α-bromo/iodo/chloroketones from olefins under visible-light irradiation conditions has been developed. In the presence of PhI(OAc)2 as promoter and under ambient conditions, the reactions of styrenes and triiodomethane undergo the transformation smoothly to deliver the corresponding α-iodoketones without additional photocatalyst in good yields under sunlight irradiation. Meanwhile, the reactions of styrenes with tribromomethane and trichloromethane generate the desired α-bromoketones and α-chloroketones in high yields by using Ru(bpy)3Cl2 as a photocatalyst under blue LED (450–455 nm) irradiation.
- Wang, Zhihui,Wang, Lei,Wang, Zhiming,Li, Pinhua,Zhang, Yicheng
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supporting information
p. 429 - 432
(2020/02/29)
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- Facile Synthesis of α-Haloketones by Aerobic Oxidation of Olefins Using KX as Nonhazardous Halogen Source
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An operationally simple and safe synthesis of α-haloketones using KBr and KCl as nonhazardous halogen sources is reported. It involves an iron-catalysed reaction of alkenes with KBr/KCl using O2 as terminal oxidant under the irradiation of visible-light. This strategy avoids the risks associated with handling halo-contained electrophiles (Cl2, Br2, NCS, NBS). The process is tolerant to several functional groups, and extended to a range of substituted styrenes in up to 89% yield. A radical reaction pathway is proposed based on control experiments and spectroscopy studies.
- Luo, Zhibin,Meng, Yunge,Gong, Xinchi,Wu, Jie,Zhang, Yulan,Ye, Long-Wu,Zhu, Chunyin
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supporting information
p. 173 - 177
(2020/01/02)
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- The Mn-catalyzed paired electrochemical facile oxychlorination of styrenes: Via the oxygen reduction reaction
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Reported herein is the electrochemical engendering of chlorine radicals by a manganese catalyst with a controllable pattern, and inexpensive MgCl2 as the chlorine source. In combination with the oxygen reduction reaction, chloroacetophenones were synthesized with abundant styrene as the feedstock in good to excellent yields.
- Tian, Siyu,Jia, Xiaofei,Wang, Ling,Li, Baoying,Liu, Siyuan,Ma, Li,Gao, Wei,Wei, Yingqin,Chen, Jianbin
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supporting information
p. 12104 - 12107
(2019/10/14)
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- CV-driven Optimization: Cobalt-Catalyzed Electrochemical Expedient Oxychlorination of Alkenes via ORR
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Instead of screening reaction conditions by yield-based chemical trial-and-error, potential-based cyclic voltammetry was alternatively employed for optimization of electrochemical oxychlorination of alkenes. With this unconventional screening method, the catalyst system including catalysts, molar ratio of chloride sources and solvents were identified in a rational, time- and energy-efficient manner. The optimal catalytic system in combination with oxygen reduction reaction enabled broad substrate scopes for the desired transformation by taking advantages of persistent radical effect. UV-vis and CV titration experiments confirmed the in-situ formed catalytic species [CoCl5]. Moreover, cyclic voltammetry was applied to obtain mechanistic insights in our reaction system. (Figure presented.).
- Tian, Siyu,Lv, Shide,Jia, Xiaofei,Ma, Li,Li, Baoying,Zhang, Guofeng,Gao, Wei,Wei, Yingqin,Chen, Jianbin
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supporting information
p. 5626 - 5633
(2019/11/22)
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- Iodine-DMSO-promoted divergent reactivities of arylacetylenes
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An unprecedented set of efficient, economical, atom-economic and exceedingly selective I2-DMSO-promoted methods is described for the generation of different structures. The reaction represents the first of its kind, involving the use of different iodine concentrations, temperatures, acids and salt to adjust the selectivity for the synthesis of different alkenes, α-functionalized ketones and α-ketomethylthioesters.
- Rather, Suhail A.,Kumar, Atul,Ahmed, Qazi Naveed
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supporting information
p. 4511 - 4514
(2019/04/26)
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- Direct conversion of alcohols to α-chloro aldehydes and α-chloro ketones
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Direct conversion of primary and secondary alcohols into the corresponding α-chloro aldehydes and α-chloro ketones using trichloroisocyanuric acid, serving both as stoichiometric oxidant and α-halogenating reagent, is reported. For primary alcohols, TEMPO has to be added as an oxidation catalyst, and for the transformation of secondary alcohols (TEMPO-free protocol), MeOH as an additive is essential to promote chlorination of the intermediary ketones.
- Jing, Yuanyuan,Daniliuc, Constantin G.,Studer, Armido
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supporting information
p. 4932 - 4935
(2015/04/27)
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- A simple and convenient method for direct α-chlorination of ketones with ammonium chloride and Oxone
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When ketones were treated with ammonium chloride and Oxone in MeOH at room temperature, a direct α-chlorination of ketones was occurred and a series of the corresponding α-chloroketones were obtained in moderate to good yields after 24 h. In this reaction, ammonium chloride was used as the source of chlorine and Oxone was used as an oxidant. This method was simple, convenient and providing a novel procedure for preparation of α-chloroketones.
- Zhou, Zhong Shi,Li, Li,He, Xue Han
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p. 1213 - 1216,4
(2020/09/16)
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- Mild and efficient α-chlorination of carbonyl compounds using ammonium chloride and oxone (2KHSO5·KHSO4· K2SO4)
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A simple protocol for the α-monochlorination of ketones and 1,3-dicarbonyl compounds utilizing NH4Cl as a source of chlorine and Oxone as an oxidant in methanol without catalyst is presented. The reaction proceeds at ambient temperature in yields ranging from moderate to excellent.
- Swamy, Peraka,Kumar, MacHarla Arun,Reddy, Marri Mahender,Narender, Nama
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supporting information; experimental part
p. 432 - 434
(2012/06/01)
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- α-Halogenation of carbonyl compounds: Halotrimethylsilane-nitrate salt couple as an efficient halogenating reagent system
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A mixture of chloro/bromotrimethylsilane and nitrate salt is found to be an effective reagent system for the α-chlorination/bromination of carbonyl compounds. The reaction occurs under mild conditions yielding the products in moderate to good yields.
- Prakash, G.K. Sxurya,Ismail, Rehana,Garcia, Jessica,Panja, Chiradeep,Rasul, Golam,Mathew, Thomas,Olah, George A.
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experimental part
p. 1217 - 1221
(2011/03/22)
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- Enantioselective synthesis of cyclic sulfamidates via Pd-catalyzed hydrogenation
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Using Pd(CF3;CO2)2/(S,S)-f-binaphane as the catalyst, an efficient enantioselective synthesis of cyclic sulfamidates was developed via asymmetric hydrogenation of the corresponding cyclic imines in 2,2,2-trifluoroethanol at room temperature with high enantioselectivities (up to 99% ee).
- Wang, You-Qing,Yu, Chang-Bin,Wang, Da-Wei,Wang, Xiao-Bing,Zhou, Yong-Gui
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supporting information; experimental part
p. 2071 - 2074
(2009/04/18)
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- Microwave-assisted synthesis of α-hydroxy ketone and α-diketone and pyrazine derivatives from α-halo and α,α′-dibromo ketone
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A novel reaction of α-halo ketone (α-bromo and α-chloro ketone) with irradiation under microwave gave the corresponding α-hydroxyketone and pyrazine derivative in good yields. In the case of α,α′-dibromo ketone, α-diketone was obtained. This reaction affords a new, clean and convenient synthetic method for α-hydroxyketone, α-diketone, α-chloro ketone and pyrazine derivative.
- Utsukihara, Takamitsu,Nakamura, Hiroaki,Watanabe, Masashige,Akira Horiuchi
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p. 9359 - 9364
(2008/01/27)
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- Potent and subtype-selective CCK-B/gastrin receptor antagonists: 2,4-dioxo-1,5-benzodiazepines with a plane of symmetry
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A series of CCK-B/gastrin receptor antagonists, 2,4-dioxo-1,5-benzodiazepine derivatives with a plane of symmetry, were designed, synthesized, and evaluated for antagonistic activity. Structure-activity relationship studies revealed that carbonylmethyl groups at both N-1 and N-5 positions and hydrophilic groups, such as the carboxyl group on the benzene ring attached to the ureido group at the C-3 position, brought about potent affinity and subtype selectivity for CCK-B/gastrin receptors. Several compounds showed excellent in vivo inhibition of gastric acid secretion induced by pentagastrin in anesthetized rats.
- Hagishita, Sanji,Seno, Kaoru,Kamata, Susumu,Haga, Nobuhiro,Ishihara, Yasunobu,Ishikawa, Michio,Shimamura, Mayumi
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p. 1433 - 1446
(2007/10/03)
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- INVESTIGATIONS ON REACTIONS OF CHLORINE DIOXIDE AND SODIUM CHLORITE WITH ORGANIC COMPOUNDS. PART XXXV. REACTIONS OF CHLORINE DIOXIDE WITH RING-SUBSTITUTED STYRENES
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Reactions of chlorine dioxide with ring substituted styrenes (1a-n) in carbon tetrachloride at 52-54 deg C were studied.The reaction products were isolated and characterised.It has been found that methyl-, chloro-, nitrostyrenes and 4-methoxystyrene are attacked by chlorine dioxide exclusively on the vinyl group, to yield the corresponding α-chloroacetophenones (2), diastereoisomers of β-chlorostyrene (6,7), oxidation products (8,9) and some polymers.Oxidation of its phenolic hydroxyl groups and vinyl polymerization took place in hydroxystyrenes.
- Kwiecien, Halina,Jalowiczor, Jozef
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p. 811 - 824
(2007/10/02)
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- Pyridazine derivatives having a psychotropic action and compositions
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This invention relates to pyridazine derivatives substituted in the 4-position by a cyano group having psychotropic activity. It also relates to a process for the preparation of these products and their application as medicaments. STR1
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