- (2-Ethylhexyl)sodium: A Hexane-Soluble Reagent for Br/Na-Exchanges and Directed Metalations in Continuous Flow
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We report the on-demand generation of hexane-soluble (2-ethylhexyl)sodium (1) from 3-(chloromethyl)heptane (2) using a sodium-packed-bed reactor under continuous flow conditions. Thus, the resulting solution of 1 is free of elemental sodium and therefore suited for a range of synthetic applications. This new procedure avoids the storage of an alkylsodium and limits the handling of metallic sodium to a minimum. (2-Ethylhexyl)sodium (1) proved to be a very useful reagent and undergoes in-line Br/Na-exchanges as well as directed sodiations. The resulting arylsodium intermediates are subsequently trapped in batch with various electrophiles such as ketones, aldehydes, Weinreb-amides, imines, allyl bromides, disulfides and alkyl iodides. A reaction scale-up of the Br/Na-exchange using an in-line electrophile quench was also reported.
- Annapureddy, Rajasekar Reddy,Harenberg, Johannes H.,Hoefer, Carla A.,Knochel, Paul,Weidmann, Niels,Wiegand, Alexander J.
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supporting information
p. 14296 - 14301
(2021/05/07)
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- Sodium-Ketyl Radical Anions by Reverse Pinacol Reaction and Their Coupling with Iodoarenes
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Transition-metal-free C-C bond formation between aryl iodides and pinacols is presented. Pinacols are readily transformed by deprotonation with NaH to their Na-pinacolates. C-C-bond homolysis at room temperature generates in situ the corresponding Na-ketyl radical anions which react with various aryl iodides in a homolytic aromatic substitution reaction to form tertiary Na-alcoholates. Protonation eventually provides tertiary alcohols in an unprecedented route.
- Tang, Xinjun,Studer, Armido
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supporting information
p. 4448 - 4450
(2016/11/07)
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- The absolute configuration of simple aliphatic alcohols through a chemical/computational approach: triarylether derivatives of (+)-endo-2-norborneol as a case study
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The reliable determination of the absolute configuration of (+)-endo-2-norborneol 1, chosen as a representative case of simple aliphatic UV-vis transparent alcohols, was obtained by transforming this compound in its 1-naphthyl-diphenylmethyl ether 5 whose
- Mazzeo, Giuseppe,Scafato, Patrizia,Superchi, Stefano,Rosini, Carlo
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body text
p. 2435 - 2437
(2010/03/03)
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- Triaryl methane derivatives as antiproliferative agents
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Clotrimazole (CLT) 1, a synthetic anti-fungal imidazole derivative, inhibits tumor cell proliferation and angiogenesis. In the current study, flow cytometric analysis demonstrated that the decrease in tumor cell growth by CLT 1 was associated with inhibition of cell cycle progression at the G 1-S phase transition, resulting in G0-G1 arrest. A series of CLT 1 analogues has been generated in order to develop CLT 1 derivatives that are devoid of the imidazole moiety which is responsible for the hepatoxicity associated with CLT 1 while retaining CLT 1 efficacy. The majority of these analogues demonstrate in vitro antiproliferative activity ranging from submicromolar to micromolar concentrations.
- Al-Qawasmeh, Raed A.,Lee, Yoon,Cao, Ming-Yu,Gu, Xiaoping,Vassilakos, Aikaterini,Wright, Jim A.,Young, Aiping
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p. 347 - 350
(2007/10/03)
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- Palladium-catalyzed arylation of α,α-disubstituted arylmethanols via cleavage of a C-C or a C-H bond to give biaryls
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The palladium-catalyzed arylation of α,α-disubstituted arylmethanols with aryl halides proceeds not only via C-H bond cleavage at the ortho-position, but also via cleavage of the sp2-sp3 C-C bond with the liberation of ketones (β-carbon elimination) to give the corresponding biaryls. Both reactions appear to occur through common arylpalladium(II) alcoholate intermediates. The results of systematic studies with respect to which C-C or C-H bond is preferentially cleaved in the arylation are reported. Among the important findings is the selective elimination of ortho-substituted aryl groups even from aryl(diphenyl)methanols due to steric reasons. Thus, various biaryls having ortho-substituents can be produced efficiently by treatment of the corresponding aryl(diphenyl or dimethyl)methanols with aryl bromides and chlorides.
- Terao, Yoshito,Wakui, Hiroyuki,Nomoto, Michiyo,Satoh, Tetsuya,Miura, Masahiro,Nomura, Masakatsu
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p. 5236 - 5243
(2007/10/03)
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- A one-flask synthesis of dihydronaphthalenemethanols by directed addition of organolithium reagents to BHA naphthalenecarboxylates
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The 1,4-addition reaction of organolithium reagents with 2,6-bis(tert- butyl)-4-methoxyphenyl naphthalenecarboxylates gave regioselectively substituted dihydronaphthalenecarboxylates in high yields. Successive treatment of the esters with organolithiums in THF, lithium triethylborohydride, methyl iodide, and finally sodium borohydride in methanol, provided vegio- and stereoselectively the corresponding 1,1,2- and 1,2,2-trisubstituted dihydronaphthalenylmethanols in good yields. This one- flask process is constituted from a sequence of five reactions involving a reductive generation of an aldehyde metal enolate from a ketene as the key step.
- Shindo, Mitsuru,Koga, Kenji,Asano, Yasutomi,Tomioka, Kiyoshi
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p. 4955 - 4968
(2007/10/03)
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- Influence of some novel N-substituted azoles and pyridines on rat hepatic CYP3A activity
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A series of N-substituted heteroaromatic compounds structurally related to clotrimazole was synthesized, and the effects of these compounds on ethosuximide clearance in rats were determined as a measure of their abilities to induce cytochrome P4503A (CYP3A) activity. Ethosuximide clearance and in vitro erythromycin N-demethylase activity were shown to correlate. In this series, imidazole or other related heteroaromatic 'head groups' were linked to triphenylmethane or other phenylmethane derivatives. Within the series, it was found that 1-triphenylmethane-substituted imidazoles elicited the greatest increase in CYP3A activity, and that among the triphenylmethyl-substituted imidazoles, the highest activities were achieved by the substitution of F- or Cl- in either the meta or para position of one of the phenyl rings. Diphenylmethylsubstituted pyridine was effectively devoid of activity. Compounds eliciting the largest increase in CYP3A activity (viz. 1-[(3-fluorophenyl)diphenylmethyl]imidazole, 1-[(4- fluorophenyl)diphenylmethyl]imidazole, and 1-[tri-(4- fluorophenyl)methyl]imidazole) produced little or no increase in ethoxyresorufin O-dealkylase (EROD) activity (i.e. CYP1A), whereas benzylimidazole, which elicited only a small increase in CYP3A activity, produced an almost 9-fold increase in CYP1A activity. For a series of eleven compounds exhibiting a wide range of influence on CYP3A activity, a positive correlation was found between ethosuximide clearance and hepatic CYP3A mRNA levels.
- Slama, James T.,Hancock, Julie L.,Rho, Taikyun,Sambucetti, Lidia,Bachmann, Kenneth A.
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p. 1881 - 1892
(2008/04/18)
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- Process for producing benzhydrols
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There is disclosed a process for producing benzhydrls by reacting an arylmetal compound with an aromatic aldehyde. According to this process, benzhydrols useful as raw materials for medicines and photopolymerization initiators can be produced in a high yield and industrially advantageously.
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- Conjugate addition reaction of organolithiums to naphthalenecarboxylates
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Reaction of 2,6-di-tert-butyl-4-methoxyphenyl naphthalenecarboxylates with organolithiums provided the addition products to naphthalene nucleus in quantitative yield.
- Tomioka, Kiyoshi,Shindo, Mitsuru,Koga, Kenji
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p. 1739 - 1740
(2007/10/02)
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- RADICAL-ANIONS OF AROMATIC COMPOUNDS. V. EFFECT OF THE STRUCTURE OF THE ELECTROPHILE ON THE RATIO OF THE ELECTRON-DONATING AND NUCLEOPHILIC CHARACTERISTICS OF THE BENZOPHENONE RADICAL-ANION IN REACTIONS WITH N,N,N-TRIMETHYLARYLAMMONIUM PERCHLORATES
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In reaction with N,N,N-trimethylammonium perchlorates in THF the potassium salt of the benzophenone radical-anion exhibits dual reactivity, acting both as nucleophile (as SN process) and as a one-electron reducing agent (an ET process).The effect of the structure of the aryl fragment of the ammonium salt on the ratio of the rates WET/WSN is determined by the higher sensitivity of the electron transfer rate to the effect of this factor compared with nucleophilic substitution and varies in the following order: p-Methoxyphenyl p-tolyl m-tolyl phenyl m-methoxyphenyl p-biphenylyl m-chlorophenyl 1-naphthyl.I t was found that the structure of the aryl fragment of the ammonium salt has a significant effect on the regioselectivity of the methylation of the benzophenone radical-anion.
- Selivanov, B. A.,Bil'kis, I. I.,Varand, V. L.,Shteingarts, V. D.
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p. 865 - 877
(2007/10/02)
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