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ABSTRACT: Fourteen triphenylamine derivatives functionalized with fluorophenyl, methoxyphenyl, and pyridinyl groups as respective donors and acceptors were synthesized and characterized. Their photophysical properties were systematically investigated in various solvents with different polarities. The solvent-dependent Stokes shifts of these compounds were observed and analyzed by the Lippert-Mataga equation. The synthesized compounds, especially tris(4-(pyridin-4-yl)phenyl) amine, presented pH-dependent absorptions and emissions, indicating that these compounds might be used as pH sensors.
Chemistry - An Asian Journal 04/2013; · 4.50 Impact Factor
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ABSTRACT: A general and efficient synthesis of indeno[1,2]furans via a Pd-catalyzed bicyclization reaction between 2-alkynyliodobenzenes and propargylic alcohols is described. The procedure furnished indeno[1,2]furans with moderate to excellent yields and broad substrate scope. The cascade process combines the formation of one C-O bond and two C-C bonds in a single step.
The Journal of Organic Chemistry 11/2012; · 4.45 Impact Factor
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ABSTRACT: An efficient and straightforward strategy for the synthesis of tetrasubstituted imidazoles from propargyl amines, sulfonyl azides, and terminal alkynes is described. N-Sulfonyl ketenimine and aminoallene are believed to be the key intermediates for this two-step one-pot transformation.
Organic Letters 11/2012; · 5.86 Impact Factor
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ABSTRACT: The copper-catalyzed cyanation of arenes using benzyl nitrile as a cyanide anion surrogate furnishes aromatic nitriles in moderate to good yields. The cascade process involves a copper-catalyzed aerobic C-H oxidation, a retro-cyanohydrination, and a copper-catalyzed aerobic oxidative C-H functionalization.
Chemical Communications 08/2012; 48(79):9933-5. · 6.17 Impact Factor
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ABSTRACT: Ketenimines are an important class of reactive species and useful synthetic intermediates. During the last two decades several practical and versatile approaches to ketenimines have been developed, leading to exhaustive investigations on ketenimine chemistry and the discovery of a variety of highly efficient reactions. Five types of reactions for ketenimines have been reported, including nucleophilic additions (ketenimines can be used as both electrophiles and nucleophiles), radical additions, cycloaddition reactions, electrocyclic ring closure reactions, and σ rearrangements. Furthermore, numerous complex organic compounds, particularly the biologically interesting heterocycles, have been constructed using these methodologies. The review of these accomplishments is presented here.
Chemical Society Reviews 07/2012; 41(17):5687-705. · 28.76 Impact Factor
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ABSTRACT: A highly enantioselective Biginelli reaction promoted by chiral spirocyclic SPINOL-phosphoric acids has been developed. Under the optimized conditions with 5 mol% catalyst loading, a wide range of optically active dihydropyrimidinethiones (DHPMs) were obtained in high yields (up to 98%) with good to excellent enantioselectivities (up to 99% ee). The synthetic utility of this method was demonstrated by the synthesis of chiral precursors of three drugs, including (S)-Monastrol, (S)-L-771688 and (S)-SQ 32926.
Organic & Biomolecular Chemistry 05/2012; 10(22):4467-70. · 3.70 Impact Factor
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ABSTRACT: 3-Alkenylation or 3-alkylation of indole with propargylic alcohols could be efficiently controlled by the catalyst. In the presence of triflic acid, 3-alkenylation of indole occurred and a 3,4-dihydrocyclopenta[b]indole skeleton was effectively constructed in moderate to excellent yields via a cascade process. In the presence of Cu(OTf)(2,) 3-alkylation of indole resulted in the formation of 3-propargylic indole, which could be further converted into 2-iodo-1,4-dihydrocyclopenta[b]indoles in the presence of N-iodosuccinimide and boron trifluoride etherate. Possible mechanisms related to the 3-alkenylation or 3-alkylation of indole and their extension to the formation of 3,4-dihydrocyclopenta[b]indoles or 1,4-dihydrocyclopenta[b]indoles are postulated and discussed.
The Journal of Organic Chemistry 04/2012; · 4.45 Impact Factor
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ABSTRACT: Substituted triazolinones were prepared by a three-component reaction of aldehydes, hydrazines and azodicarboxylates using
TFA as a catalyst. The procedure was convenient and efficient, utilizing readily available substrates. A plausible mechanism
for the cascade process is proposed.
Keywordstriazolinones-cascade reactions-multicomponent reactions (MCRs)-azodicarboxylates
Chinese Science Bulletin 04/2012; 55(25):2879-2884. · 1.32 Impact Factor
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ABSTRACT: Chiral SPINOL-phosphoric acids are highly enantioselective catalysts for the asymmetric Pictet-Spengler reaction of N(b) -α-naphthylmethyl tryptamines with a series of aliphatic and aromatic aldehydes, affording optically active tetrahydro-β-carbolines in excellent yields and ee values. The current protocol has been applied in the asymmetric total synthesis of (-)-harmicine.
Chemistry 03/2012; 18(11):3148-52. · 5.93 Impact Factor
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ABSTRACT: Pyruvate kinase M2 (PKM2) is a rate-limiting enzyme of aerobic glycolysis in cancer cells and plays important roles in cancer metabolism and growth. Here we show that vitamin K(3) and K(5) (VK(3) and VK(5)) are relatively specific PKM2 inhibitors. VK(3) and VK(5) showed a significantly stronger potency to inhibit PKM2 than to inhibit PKM1 and PKL, 2 other isoforms of PK dominantly expressed in most adult tissues and liver. This study combined with previous reports supports that VK(3) and VK(5) have potential as adjuvant for cancer chemotherapy.
Cancer letters 11/2011; 316(2):204-10. · 4.86 Impact Factor
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ABSTRACT: We report herein a three-component reaction of propargylic alcohols with 2-butynedioates and secondary amines, which furnished functionalized dihydroazepines. In the cases where benzylmethylamine and benzyl-i-propylamine were used as the secondary amine, the reaction afforded 2,5-dihydro-1H-pyrroles and 2,3-dihydro-1H-pyrroles, respectively, as the major product along with the desired dihydroazepines. The reaction mode depends on the electronic and steric effect of the substitutents on the secondary amines used. A tentative mechanism for this cascade process is postulated. The key intermediate is ascribed to 1,3,4-pentatrien-1-amine, which is formed by trapping the in situ generating allenic carbocation with enamine. Because of the reactivity of 1,3,4-pentatrien-1-amine formed, different products were thus formed.
The Journal of Organic Chemistry 09/2011; 76(21):8922-9. · 4.45 Impact Factor
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ABSTRACT: Polysubstituted pyrroles are regiospecifically synthesized via the copper-catalyzed three-component reaction of α-diazoketones, nitroalkenes, and amines under aerobic conditions. The cascade process involves an N-H insertion of carbene, a copper-catalyzed oxidative dehydrogenation of amine, and a [3 + 2] cycloaddition of azomethine ylide.
Organic Letters 08/2011; 13(17):4668-71. · 5.86 Impact Factor
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Chemistry 07/2011; 17(36):9920-3. · 5.93 Impact Factor
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ABSTRACT: Polysubstituted pyrroles were efficiently synthesized in moderate yields by a one-pot multicomponent reaction starting from primary amines, ethyl glyoxalate and 2-bromoacetophenones in the presence of pyridine in refluxing acetonitrile. This methodology was utilized to synthesize a highly substituted benz[g]indole.
Chemical Communications 06/2011; 47(23):6620-2. · 6.17 Impact Factor
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ABSTRACT: An efficient and straightforward strategy for the synthesis of 4-methylene-1-(phenylsulfonyl)-4,5-dihydro-1H-pyrazole from propargyl alcohol and N-sulfonylhydrazone is described. N-Sulfonyl allenamide is postulated to be the key intermediate for this tandem transformation.
Organic Letters 06/2011; 13(14):3553-5. · 5.86 Impact Factor
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ABSTRACT: Four different types of fused arenes, including fluoranthene, indeno[2,1-a]phenalene, (8H)cyclopenta[a]acenaphthylene, and pyridine[a]acenaphthylene, were efficiently constructed through iodine-mediated electrophilic cyclizations of 1,8-dialkynyl naphthalenes in a single step. Theoretical calculations supported our hypothesis that these reactions had high regioselectivity. Oxidative coupling of the fluoranthene skeleton, followed by aromatization, effectively synthesized perylene derivative 14, which emitted light at 597 nm in dichloromethane with an emission efficiency of 0.81 referred to 5,6,11,12-tetraphenylnaphthacene as a standard.
Chemistry 05/2011; 17(29):8105-14. · 5.93 Impact Factor
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ABSTRACT: Allenephosphoramides were prepared from propargyl alcohols and diethyl arylphosphoramides using Yb(OTf)(3) as catalyst. In the presence of iodine, 4,9-dihydro-2H-benzo[f]isoindole derivatives could be efficiently constructed from the same two starting materials in a single step.
Organic Letters 03/2011; 13(5):940-3. · 5.86 Impact Factor
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ABSTRACT: Phenalenone derivatives were efficiently constructed from 1,8-diiodonaphthalene and tertiary propynols via a one-pot domino reaction which eventually included Pd-catalyzed Sonogoshira coupling, Pd-catalyzed allylic oxidation and Pd-catalyzed C(sp(2))-H activation. Moreover, the synthesized phenalenone derivative presented a practical application as a fluorescent chemosensor for fluoride anion with high sensitivity and selectivity.
Chemical Communications 03/2011; 47(9):2628-30. · 6.17 Impact Factor
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ABSTRACT: A three-component reaction of indoles, sulfonyl azides and terminal alkynes afforded 3-functionalized indoles in a single step via copper-cascade catalysis.
Chemical Communications 02/2011; 47(11):3275-7. · 6.17 Impact Factor
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ABSTRACT: An efficient and straightforward strategy for the synthesis of N-(2-haloinden-1-yl)arenesulfonamides from propargylic alcohols and sulfonamides is described. Allenesulfonamide is postulated to be the key intermediate for this tandem transformation.
Organic Letters 01/2011; 13(5):1024-7. · 5.86 Impact Factor
