- Lithiomethyl ethyl ether from chloromethyl ethyl ether via a DTBB-catalysed lithiation
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The reaction of equimolar amounts of chloromethyl ethyl ether (1) and a carbonyl compound [Bu(n)CHO, Bu(t)CHO, PhCHO, Pr(i)2CO, Bu(t)2CO, (CH2)4CO, 2-cyclohexenone, PhCOMe] with an excess of lithium powder (1:7 molar ratio) and a catalytic amount of DTBB (5 mol%) in THF at 0°C (Method A) leads, after hydrolysis, to the corresponding hydroxyethers 2. The reaction can be also carried out in a two-step process: tandem lithiation at -90°C and reaction with the electrophile [Bu(n)CHO,(CH2)4CO, PhCOMe, PhMe2SiCl, CO2, PhCN, PhCONMe2, CyNCO, PhN=CHPh] at -90 to -60°C (Method B).
- Guijarro, Albert,Mancheno, Balbino,Ortiz, Javier,Yus, Miguel
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Read Online
- -Annulation of pyridinium ylides with 1-chloro-2-nitrostyrenes unveils a tubulin polymerization inhibitor
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Indolizines and pyrazolo[1,5-a]pyridines were prepared via [3 + 2]-cycloaddition of pyridinium ylides to 1-chloro-2-nitrostyrenes. The synthesized molecules were evaluated for antiproliferative activities against a BE(2)-C neuroblastoma cell line with several compounds decreasing the viability of cancer cells. Indolizine 9db showed higher potency than that of all-trans-retinoic acid, an approved cancer drug. Mechanistically, it was found to inhibit tubulin polymerization and it is thus proposed that the discovered chemistry can be exploited for the development of novel microtubule-targeting anticancer agents.
- Aksenov, Alexander V.,Aksenov, Dmitrii A.,Aksenov, nicolai A.,Arutiunov, nikolai A.,Betancourt, Tania,Du, Liqin,Grishin, Igor Yu.,Kirilov, nikita K.,Kornienko, Alexander,Rubin, Michael,Wang, Huifen,pelly, Stephen C.
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p. 7234 - 7245
(2021/08/30)
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- Regioselective Vinylation of Remote Unactivated C(sp3)?H Bonds: Access to Complex Fluoroalkylated Alkenes
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Regioselective incorporation of a particular functional group into aliphatic sites by direct activation of unreactive C?H bonds is of great synthetic value. Despite advances in radical-mediated functionalization of C(sp3)?H bonds by a hydrogen-atom transfer process, the site-selective vinylation of remote C(sp3)?H bonds still remains underexplored. Reported herein is a new protocol for the regioselective vinylation of unactivated C(sp3)?H bonds. The remote C(sp3)?H activation is promoted by a C-centered radical instead of the commonly used N and O radicals. The reaction possesses high product diversity and synthetic efficiency, furnishing a plethora of synthetically valuable E alkenes bearing tri-/di-/mono-fluoromethyl and perfluoroalkyl groups.
- Wu, Shuo,Wu, Xinxin,Wang, Dongping,Zhu, Chen
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p. 1499 - 1503
(2019/01/04)
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- Direct Synthesis of α-Alkoxy Ketones by Oxidative C–O Bond Formation
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A convenient method to prepare α-alkoxy ketones has been developed by oxidative coupling of aryl methyl ketones and alcohols. With aqueous tert-butyl hydroperoxide (6.0 equiv.) as the oxidant, tetrabutylammonium iodide (20 mol-%) as the catalyst, and TsNHNH2(1.0 equiv.) as the additive, ketones underwent direct alkoxylation to give α-methoxy or α-ethoxy ketones in moderate to good yields.
- Yu, Hui,Xu, Yilan,Fang, Yan,Dong, Rui
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p. 5257 - 5262
(2016/11/13)
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- Highly efficient synthesis of functionalized α-oxyketones: Via Weinreb amides homologation with α-oxygenated organolithiums
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An efficient, chemoselective homologation of Weinreb amides to the corresponding variously substituted α-oxyketones has been developed via the addition of lithiated α-oxygenated species. This one-step, experimentally easy, high yielding protocol is amenable not only for accessing simple α-oxyketones but also for more complex substituted ones ranging from primary and secondary alkyl-type to aromatic ones. Full delivery of the stereochemical information contained in the starting materials is observed through both the employment of enantioenriched Weinreb amides and optically active organolithium species.
- Pace, Vittorio,Murgia, Irene,Westermayer, Sophie,Langer, Thierry,Holzer, Wolfgang
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supporting information
p. 7584 - 7587
(2016/07/06)
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- Stereoselective Ketone Rearrangements with Hypervalent Iodine Reagents
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The first stereoselective version of an iodine(III)-mediated rearrangement of arylketones in the presence of orthoesters is described. The reaction products, α-arylated esters, are very useful intermediates in the synthesis of bioactive compounds such as ibuprofen. With chiral lactic acid-based iodine(III) reagents product selectivities of up to 73 % ee have been achieved.
- Malmedy, Florence,Wirth, Thomas
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supporting information
p. 16072 - 16077
(2016/10/30)
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- Flexible stereoselective functionalizations of ketones through umpolung with hypervalent iodine reagents
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The functionalization of carbonyl compounds in the α-position has gathered much attention as a synthetic route because of the wide biological importance of such products. Through polarity reversal, or "umpolung", we show here that typical nucleophiles, such as oxygen, nitrogen, and even carbon nucleophiles, can be used for addition reactions after tethering them to enol ethers. Our findings allow novel retrosynthetic planning and rapid assembly of structures previously accessible only by multistep sequences. A Nu approach: An efficient α-functionalization of ketones with a range of simple and useful nucleophiles is possible by using hypervalent iodine reagents (see scheme; Nu′ can be the Nu itself or a protected form of this nucleophile group).
- Mizar, Pushpak,Wirth, Thomas
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p. 5993 - 5997
(2014/06/10)
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- Transformation of aryl acyloin O-alkyl and O-phenyl derivatives to ketones
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The treatment of aryl acyloin (α-hydroxyketone) O-alkyl and O-phenyl derivatives with 2-3 equiv of Zn and 1-2 equiv of NH4Cl in ethanol, refluxing for 20-120 min, gave the corresponding ketones with excellent yields. Further, α,β-epoxy ketones can be efficiently transformed to β-hydroxy ketones, and 2,2-dialkoxy-1-phenyl ketone also can be dealkoxylated to 1-phenyl ketone. Copyright Taylor & Francis Group, LLC.
- Yao, Zhiyi,Ye, Deju,Liu, Hong,Chen, Kaixian,Jiang, Hualiang
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p. 149 - 156
(2007/10/03)
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- Indium triflate: A mild and efficient Lewis acid catalyst for O-H insertion reactions of α-diazo ketones
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Facile O-H insertion reactions of α-diazo ketones with aliphatic/aromatic alcohols or benzenethiol have been developed in the presence of indium triflate as a catalyst. These reactions provided good yields of α-alkoxy ketones. A comparative study with other Lewis acids establishes the reactivity of indium triflate in O-H insertion reactions of α-diazo ketones.
- Muthusamy, Sengodagounder,Babu, Srinivasarao Arulananda,Gunanathan, Chidambaram
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p. 3133 - 3136
(2007/10/03)
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- A new and mild heterogeneous catalytic decomposition of α-diazo carbonyl compounds using montmorillonite or zeolite
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A very mild method of decomposition of various α-diazo carbonyl compounds 1 in the presence of environmentally attractive solid acids such as montmorillonite K-10 or zeolite H-Y in a heterogeneous manner to furnish α-hydroxy/alkoxy ketones in very good yield is reported. Interestingly, novel bicycloalkane-1,3-diones and 3-furanones were obtained as unusual products in the case of aliphatic/alicyclic α-diazo carbonyl compounds.
- Muthusamy, Sengodagounder,Babu, Srinivasarao Arulananda,Gunanathan, Chidambaram,Jasra, Raksh Vir
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p. 407 - 410
(2007/10/03)
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- Ketone precursors for organoleptic compounds
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The invention discloses ketones of formula I: wherein, Y is an optionally substituted alkyl, cycloalkyl, or cycloalkylalkyl, wherein each alkyl group is straight or branched and each alkyl and cycloalkyl group is saturated or unsaturated; R1is hydrogen or a C1-6alkyl group that is substituted, saturated or unsaturated, straight or branched; A is a chromophoric substituted aromatic ring or ring system; n is an integer; and with the proviso that formula I is not 2-ethoxy-1-phenyl-ethanone. These compositions are useful for the delivery of organoleptic compounds, especially of flavors, fragrances, masking agents and antimicrobial compounds.
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- Chemical compounds
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This invention relates to phenylpyridone derivatives which have bronchodilator and anti-allergic activities. A compound of the invention is 6-(2-propoxyphenyl)-1,2-dihydro-2-oxopyridine-3-carboxamide.
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- Synthesis and Muscarinic Cholinergic Receptor Affinities of 3-Quinuclidinyl α-(Alkoxyalkyl)-α-aryl-α-hydroxyacetates
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Seven analogues of 3-quinuclidinyl benzilate (QNB) in which one phenyl ring was replaced by an alkoxyalkyl moiety were synthesized and their affinities for the muscarinic cholinergic receptor determined.An oxygen in the β-position of the moienty was not w
- Cohen, Victor I.,Gibson, Raymond E.,Fan, Linda H.,Cruz, Rosanna De La,Gitler, Miriam S.,et al.
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p. 2989 - 2993
(2007/10/02)
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- Metal-Metal Exchange of α-Metallo Ketones. Novel Formation of α-Acyl Anion and α-Keto Carbonium Ion Equivalents from (Aryl)phenacyl TlIII, PbIV, and HgII Systems
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The novel class of α-metallo ketones RCOCH2TlIIItolyl(OCOCF3) where R = phenyl, substituted phenyl, thienyl, pyridinyl, and tert-butyl have been synthesized and characterized by 1H NMR and 13C NMR.These compounds serve as anion equivalents in the TiCl4-mediated aldol condensation.Metal-metal exchange with iodosylbenzene or lead tetraacetate leads to α-nucleophilic substitution derived from the formal α-keto carbonium ion equivalent.The corresponding p-CH3OC6H4COCH2PbIVC6H4OCH3-p-(OCOCH3)2 and (p-CH3OC6H4COCH2)2HgII analogues were synthesized and shown to likewise behave as either enolate anion or α-keto carbonium ion equivalents upon metal-metal exchange with TiIV, PbIV, or IIII.The importance of this work is that the range of reactivity of α-metallo ketones may be selectively adjusted by metal-metal or metal-metalloid exchange.
- Moriarty, Robert M.,Penmasta, Raju,Prakash, Indra,Awasthi, Alok K.
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p. 1022 - 1025
(2007/10/02)
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- Hypervalent iodine oxidation of silyl enol ethers under Lewis acid conditions in methanol. A general route to α-methoxy ketones
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Hypervalent iodine oxidation of various silyl enol ethers (aromatic, heteroaromatic, aliphatic) using iodosobenzene-boron trifluoride etherate in methanol leads to α-methoxylation of ketones in high yields. The scope and mechanism of the reaction are discussed.
- Moriarty, Robert M.,Prakash, Om,Duncan, Michael P.,Vaid, Radhe K.,Musallam, Hikmat A.
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p. 150 - 153
(2007/10/02)
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- α-METHOXY KETONES BY THE REACTION OF TRIMETHYLSILYL ENOL ETHERS WITH LEAD TETRAACETATE IN METHANOL
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Trimethylsilyl enol ethers of acetophenone, 2-acetylthiophene and 2-acetylfuran react with lead tetraacetate in methanol at room temperature to give the α-methoxy ketones in good yields.
- Moriarty, Robert M.,Prakash, Indra,Penmasta, Raju
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p. 709 - 714
(2007/10/02)
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- Carbon-Carbon Bond Formation using Hypervalent Iodine under Lewis Acid Conditions: 1,4-Diarylbutane-1,4-diones
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Reaction of silyl enol ethers of aryl methyl ketones with PhIO-BF3*Et2O results in coupling to yield 1,4-diketones.
- Moriarty, Robert M.,Prakash, Om,Duncan, Michael P.
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- ACID-CATALYZED DECOMPOSITION OF DIAZO CARBONYL COMPOUNDS. II. SYNTHESIS OF 2- OR 5-HETEROATOM-SUBSTITUTED OXAZOLES.
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The BF//3-catalyzed decomposition of m- and p-substituted alpha -diazoacetophenones in excess of methyl thiocyanate and ethyl thiocyanate gave the corresponding 2-methylthio-, and 2-ethylthio-5-aryloxazoles, respectively in good yields along with s-alkyl-
- Ibata,Yamashita,Kashiuchi,Nakano,Nakawa
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p. 2450 - 2455
(2007/10/02)
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