- 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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- Iridium-Catalyzed Asymmetric Hydrogenation of Halogenated Ketones for the Efficient Construction of Chiral Halohydrins
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Iridium-catalyzed asymmetric hydrogenation of prochiral halogenated ketones was successfully developed to prepare various chiral halohydrins with high reactivities and excellent enantioselectivities under basic reaction condition (up to >99% conversion, 99% yield, >99% ee). Moreover, gram-scale experiment was performed well in the presence of just 0.005 mol% (S/C=20 000) Ir/f-amphox catalyst with 99% yield and >99% ee. (Figure presented.).
- Yin, Congcong,Wu, Weilong,Hu, Yang,Tan, Xuefeng,You, Cai,Liu, Yuanhua,Chen, Ziyi,Dong, Xiu-Qin,Zhang, Xumu
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supporting information
p. 2119 - 2124
(2018/04/30)
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- Facile and efficient preparation of α-halomethyl ketones from α-diazo ketones catalyzed by iron(III) halides and silica gel
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An efficient and mild method for the synthesis of α-halomethyl ketones from α-diazo ketones was developed using ferric chloride or bromide as the halogen source and silica gel as the hydrogen source, with good to excellent yields.
- Shi, Xinxia,Zhang, Lingqiong,Yang, Pengfei,Sun, Han,Zhang, Yilan,Xie, Chunsong,Ou-yang, Zhen,Wang, Min
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supporting information
p. 1200 - 1203
(2018/03/08)
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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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- Target-oriented synthesis: Miscellaneous synthetic routes to access 1,4-enediones through the coupling of 1,3-dicarbonyl compounds with multiform substrates
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Target-oriented synthetic protocol was presented for the synthesis of 1,4-enediones. The approach can efficiently construct 1,4-enediones through different reaction pathways from multiform substrates α-halo aromatic ketones, 2-hydroxy-aromatic ketones and methyl carbinols. In this reaction, CuI was found to be the most efficient catalyst. Multiform substrates were also found to perform well to afford the products in a one-pot fashion.
- Zhu, Yan-Ping,Cai, Qun,Gao, Qing-He,Jia, Feng-Cheng,Liu, Mei-Cai,Gao, Meng,Wu, An-Xin
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p. 6392 - 6398
(2013/07/25)
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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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- Aracyl triflates as derivatizing agents for biological betaines
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Several trifluoromethanesulfonates of general structure ArCOCH 2OTf were prepared and their suitability for use as derivatizing agents for the HPLC analysis of betaines was assessed. Four of them (Ar=2′-naphthyl, 2′-fluorenyl, 6′-methoxynaphtha
- Happer, D. Alan R.,Hayman, Colin M.,Storer, Malina K.,Lever, Michael
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p. 467 - 472
(2007/10/03)
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- Synthesis, characterization and in-vitro antifungal evaluation of some dithiocarbamic acid derivatives
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Some new N, N-disubstituted dithiocarbamates derived from α-acetonaphthone and their precursors, potassium salts of dithiocarbamic acid, were prepared and evaluated for antifungal activity. Synthesis involved the reaction of α-chloro-2-acetonaphthone or α-chloro-4-methoxy-1-acetonaphthone with the potassium salts of N, N-disubstituted dithiocarbamic acid (5a-g). Compounds 5a-g were readily produced by reaction of equivalent amounts of the appropriate secondary amine, potassium hydroxide and carbon disulphide. The purity of the final derivatives, N, N-disubstituted dithiocarbamates 6a-g and 7a-g, was determined elemental analyses and TLC, and assignment of structures was confirmed by IR, 1H NMR, 13C NMR and MS. Preliminary evaluation of the antifungal activity of derivatives 5a-g, 6a-g and 7a-g was determined in-vitro at a 2.5 or 5.0% concentration against different fungal species using tolnaftate as a reference drug. The potassium salts 5a-g were the most potent derivatives of the tested series. Compounds 5a-g showed significant broad spectrum antifungal activity. Combination of the dithiocarbamate with acetonaphthonyl moiety, represented by the 6a-g and 7a-g series, resulted in a decrease in or complete loss of antifungal activity in certain derivatives. Compounds derived from 4-methoxy-1-acetonaphthone (7a-g) were generally superior to their 4-nonsubstituted congeners (6a-g). The morpholino dithiocarbamate derivative 7e was equipotent or superior to the reference drug against the tested dermatophytes species and Rhodotorula rubra at a 5% concentration. In addition, 7e exhibited inhibitory activity against Chrysosporium tropicum, Emericella nidulans, Penicillium aurantiogriseum and Aspergillus sydowii. Some derivatives of both series showed selective activity against certain fungi, (e.g. 6f against Phoma glomerata and Scopulariopsis acremonium; 6g against Emericella nidulans and Phoma glomerata; 7c against Geotrichum candidum and Mucor circinelloides; 7d against Geotrichum candidum, Penicillium aurantiogriseum and Rodotorula rubra and 7f against Mucor circinelloides).
- Mahfouz, Nadia M.,Moharram, Ahmad M.
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p. 315 - 322
(2007/10/03)
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- S4N4SbCl5 complex: a useful reagent for conversion of sterically less hindred α-bromo ketones to α-chloro ketones
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The reactions of sterically less hindered α-bromo alkyl and aryl ketones with tetrasulfur tetranitride antimony pentachloride (S4N4SbCl5) complex in toluene at reflux gave the corresponding α-chloro kerones in good to excellent yields.
- Kim, Kil-Joong,Kim, Kyongtae
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p. 4227 - 4230
(2007/10/03)
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- Ethanolamine derivatives having sympathomimetic and anti-pollakiuria activities
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This invention relates to new ethanolamine derivatives having gut selective sympathomimetic and anti-pollakiuria activities and represented by the general formula [I]: STR1 wherein R1 is aryl or a heterocyclic group, each of which may be substituted with halogen, etc., R2 is hydrogen, halogen, nitro, hydroxy, lower alkyl optionally substituted with acyl, lower alkenyl optionally substituted with acyl, lower alkoxy optionally substituted with acyl, or amino optionally substituted with acyl(lower)alkyl, R3 is hydrogen, an N-protective group, or lower alkyl optionally substituted with lower alkylthio, n is an integer of 0 to 3, and a heavy solid line means a single bond or a double bond, provided that when n is 1, then 1) R1 is a condensed aromatic hydrocarbon group or a heterocyclic group, each of which may be substituted with halogen, etc., and the like, and pharmaceutically acceptable salts thereof to processes for the preparation thereof and to a pharmaceutical composition comprising the same.
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- Ligand Exchange Reaction of Sulfoxides in Organic Synthesis: A New Synthesis of α-Chloroketones from Carbonyl Compounds with One-Carbon Homologation
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A new procedure for one-carbon homologation of carbonyl compounds to α-chloroketones is described.Addition of the carbanion of dichloromethyl phenyl sulfoxide with ketones and aldehydes gave the adducts, chloro alcohols, in good yields.Treatment of the chloro alcohols with EtMgBr or lithium diisopropylamide gave one-carbon homologated α-chloroketones via β-oxido carbenoid rearrangement in moderate to good yields.One-carbon homologation of esters to α-chloroketones was realized via the ligand exchange reaction of the sulfinyl group of α-chloro α-sulfinyl ketones, which were synthesized from methyl esters and chloromethyl phenyl sulfoxide, with EtMgBr.
- Satoh Tsuyoshi,Mizu, Yasuhiro,Kawashima, Taku,Yamakawa, Koji
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p. 703 - 710
(2007/10/02)
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- α-Chlorination of Aromatic Acetyl Derivatives with Benzyltrimethylammonium Dichloroiodate
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Reaction of aromatic acetyl derivatives with benzyltrimethylammonium dichloroiodate in refluxing dichloroethane/methanol for several hours gave α-chloroacetyl derivatives in good yields.
- Kajigaeshi, Shoji,Kakinami, Takaaki,Moriwaki, Masayuki,Fujisaki, Shizuo,Maeno, Kimihiro,Okamoto, Tsuyoshi
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p. 545 - 546
(2007/10/02)
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- Synthetic Studies on Indoles and Related Compounds. XV. An Unusual Acylation of Ethyl Indole-2-Carboxylate in the Friedel-Crafts Acylation
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The Friedel-Crafts reaction of ethyl indole-2-carboxylate (1a) with acyl chlorides or acid anhydrides in the presence of Lewis acids was investigated in order to establish a preparative procedure for the corresponding ethyl 3-acylindole-2-carboxylates (4).Although monoacylation occured successfully, the products were generally a mixture of ethyl 3-, 5-, and 7-acylindole-2-carboxylates (4,5 and 6).The ratio of the yields of these three products varied greatly depending on reaction conditions and reagents used.A tendency that the 3-acylindole (4) was obtained as a main product was observed when a Lewis acid other than aluminum chloride was used as a catalyst and/or an acyl chloride derived from a weaker acid was employed, whereas a tendency for formation of the 5- and 7-acylindoles (5 and 6) was observed when aluminum chloride and/or an acyl chloride derived from a stronger acid was used.As to the 5- and 7-acylindoles (5 and 6) , the yields of the former were always much higher than those of the latter (6).The result indicates that ethyl 3- and 5-acylindole-2-carboxylates can be regioselectively prepared from a common substrate (1a) by changing the reaction conditions or reagents. friedel-craft acylation; ethyl indole-2-carboxylate; acyl chloride; acid anhydride; lewis acid; aluminum chloride; acylindole
- Murakami, Yasuoki,Tani, Masanobu,Tanaka, Kenjiro,Yokoyama, Yuusaku
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p. 2023 - 2035
(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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- DIRECTION OF ACYLATION OF NAPHTHALENE BY THE FRIEDEL-CRAFTS METHOD
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The Friedel-Crafts acylation of naphthalene by the halides of substituted and unsubstituted aliphatic carboxylic acids with various chain lengths (C2-C6) and various degrees of branching in the hydrocarbon chain was investigated.The effect of the solvent on the direction of acylation shows up during acylation by the least hindered acylating agents (acetyl chloride, acetyl bromide, chloroacetyl chloride, and bromoacetyl bromide).The α isomer is obtained preferentially in chloroform and the β isomer in nitrobenzene.With increase in the length and degree of branching of the hydrocarbon chain the β position of the naphthalene ring becomes the preferred direction of acylation.The main factor which determines the direction of Friedel-Crafts acylation in naphthalene is the steric factor.
- Dumpis, M. A.,Kudryashova, N. I.,Khromov-Borisov, N. V.
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p. 1799 - 1803
(2007/10/02)
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