- Generation and reaction of cyano-substituted aryllithium compounds using microreactors
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We developed a microflow method for the generation and reactions of aryllithiums bearing a cyano group, including o-lithiobenzonitrile, m-lithiobenzonitrile and p-lithiobenzonitrile. The method was effective at much higher temperatures than are required for conventional macrobatch reactions, by virtue of rapid mixing, short residence time, and efficient temperature control. In addition, reactions of o-lithiobenzonitrile with carbonyl compounds followed by trapping of the resulting lithium alkoxides with electrophiles were achieved in an integrated microflow system. The Royal Society of Chemistry.
- Nagaki, Aiichiro,Kim, Heejin,Usutani, Hirotsugu,Matsuo, Chika,Yoshida, Jun-Ichi
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supporting information; experimental part
p. 1212 - 1217
(2010/06/13)
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- Activation of functional arylzincs prepared from aryl iodides and highly enantioselective addition to aldehydes
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(Chemical Equation Presented) An easily available chiral ligand (S)-1 is found to activate the nucleophilic reaction of the arylzincs prepared in situ from the reaction of aryl iodides with Et2Zn. Both high yields and high enantioselectivity (u
- DeBerardinis, Albert M.,Turlington, Mark,Pu, Lin
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supporting information; experimental part
p. 2709 - 2712
(2009/05/27)
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- Design, synthesis, and structure-activity relationships of pyrazolo[3,4-d]pyrimidines: A novel class of potent enterovirus inhibitors
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A series of pyrazolo[3,4-d]pyrimidines were synthesized and their antiviral activity was evaluated in a plaque reduction assay. It is very interesting that this class of compounds provide remarkable evidence that they are very specific for human enteroviruses, in particular, coxsackieviruses. Some derivatives proved to be highly effective in inhibiting enterovirus replication at nanomolar concentrations. SAR studies revealed that the phenyl group at the N-1 position and the hydrophobic diarylmethyl group at the piperazine largely influenced the in vitro antienteroviral activity of this new class of potent antiviral agents. It was found that the pyrazolo[3,4-d]pyrimidines with a thiophene substituent, such as compounds 20-24, in general exhibited high activity against coxsackievirus B3 (IC50=0.063-0.089μM) and moderate activity against enterovirus 71 (IC50=0.32-0.65μM) with no apparent cytotoxic effect toward RD (rhabdomyosarcoma) cell lines (CC5025μ M).
- Chern, Jyh-Haur,Shia, Kak-Shan,Hsu, Tsu-An,Tai, Chia-Liang,Lee, Chung-Chi,Lee, Yen-Chun,Chang, Chih-Shiang,Tseng, Sung-Nien,Shih, Shin-Ru
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p. 2519 - 2525
(2007/10/03)
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- A new strategy for deprotonative functionalization of aromatics: Transformations with excellent chemoselectivity and unique regioselectivities using t-Bu-P4 base
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A new strategy for deprotonative functionalization of aromatics using t-Bu-P4 base has been developed, and highly chemoselective transformations have been achieved with unique regioselectivities. Copyright
- Imahori, Tatsushi,Kondo, Yoshinori
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p. 8082 - 8083
(2007/10/03)
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- Preparation of highly functionalized Grignard reagents by an iodine-magnesium exchange reaction and its application in solid-phase synthesis
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At -40°C aryl iodides that contain other functional groups can be selectively converted into Grignard reagents, which react with electrophiles such as benzaldehyde in the usual manner [Eq. (a)]. Aryl bromides and iodides that are immobilized as esters on a Wang resin behave analogously.
- Boymond, Laure,Rottlaender, Mario,Cahiez, Gerard,Knochel, Paul
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p. 1701 - 1703
(2007/10/03)
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- New formulas for organozincate chemistry
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As a new type of zincate, we designed various new organozinc derivatives, Me3Zn(R)Li2 (R = Me, CN, SCN), which could be prepared in situ from lithium trimethylzincate and anion species such as methyllithium, lithium cyanide, and lithium thiocyanate. We investigated the reactivities of these zincates toward the halogen (or tellurium)-zinc exchange, Michael addition, carbozincation, and epoxide ring opening reactions. On the basis of their excellent chemical yields and chemoselectivities, these species were considered to be differentiated from ordinary triorganozincates, R3ZnLi. We also discuss the structure of the newly designed zincates using 1H NMR/Raman/in situ FTIR/extended X-ray absorption the structure (EXAFS) spectroscopic and the density functional theory (DFT) theoretical studies. All results strongly support the fact that these newly designed zincates are a new category of zincate species. This observation is also identical with the fact that newly designed zincates have a higher and unique reactivity compared to the conventional triorganozincates.
- Uchiyama, Masanobu,Kameda, Mitsuyoshi,Mishima, Osamu,Yokoyama, Nobuko,Koike, Minako,Kondo, Yoshinori,Sakamoto, Takao
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p. 4934 - 4946
(2007/10/03)
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- Deactivation of Triplet Phenyl Alkyl Ketones by Conjugatively Electron-Withdrawing Substituents
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Para-cyano, -carbomethoxy, and -acyl substituents decrease the triplet reactivity of valerophenone (γ-hydrogen abstraction), whereas comparable meta substituents increase reactivity.Spectroscopic results are presented which indicate that para-(-R) substituents lower ?,?* triplet energies so much more than n,?* energies that the lowest triplets become largely ?,?* in nature.Meta-(-R) substituents do not stabilize ?,?* triplets enough to invert triplet levels.Both substitution patterns support a largely 1,4-biradical structure for the lowest ?,?* triplet of acylbenzenes.Ortho substituents show the usual steric anomalies: ortho cyano enhances valerophenone triplet reactivity by stabilizing the n,?* triplet; ortho carbomethoxy deactivates valerophenone by stabilizing the ?,?* triplet but not the n,?.*
- Wagner, Peter J.,Siebert, Elizabeth J.
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p. 7329 - 7335
(2007/10/02)
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