- Synthesis of 1,5-naphthylethynyl nanostructure networks with extended π-conjugation. Effective heterocoupling catalyzed by palladium under a compatible CO2 atmosphere
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The synthesis of a new extended π-conjugated 5-N,N-dimethylaminonaphthyl family was undertaken by palladium-catalyzed cross-coupling reaction between a protected 5-iodonaphthylethynyl and 1-ethynyl-5-(N,N-dimethylamino)naphthalene. Under an argon atmosphere, only the homocoupling product 1,4-(N,N-dimethylamino)naphthyl-1,3-butadiyne was isolated, in excellent yield. However, under a compatible and pure carbon dioxide atmosphere, the cross-coupling product was obtained in excellent yield.
- Rodríguez, J. Gonzalo,Tejedor, J. Luis
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p. 2691 - 2693
(2007/10/03)
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- Carbon networks based on 1,5-naphthalene units. Synthesis of 1,5-naphthalene nanostructures with extended π-conjugation
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The synthesis and spectroscopic characterization of nanometer-sized conjugated molecules of 5-X-naphthylethynyl (X= NO2, NMe2) units with precise length and constitution have been carried out. A new extended π-conjugated 5-nitronaphthyl family was synthesized by palladium-catalyzed cross-coupling reaction between the protected 5-iodonaphthylethynyl 5a and 1-ethynyl-5-nitronaphthalene 9, or the resulting ethynyl compound 11 and the 1-iodo-5-nitronaphthalene 3. Catalytic oxidative dimerization of the terminal acetylene compounds permits the isolation of the corresponding 1,3-butadiyne derivatives 16-18, with the nitro groups at the ends of the conjugation, in excellent yields. A new family of conjugated 5-nitro-(naphthylethynyl)-[5-(N,N-dimethylamino)]-naphthalene (20-22), was also synthesized by palladium-catalyzed cross-coupling reaction between 5-iodo-N,N-dimethylnaphthalene-1-amine (19) with the appropriate terminal acetylene (9, 11, and 13 respectively). Compounds 20-22 show a fluorescence emission and also exhibit a charge-transfer absorption in the visible spectrum. X-ray structure of 20 confirms a centrosymmetric dimer association with an interplanar distance of 3.43 A, and the naphthalene rings adopt an anti conformation around the C≡C triple bond.
- Rodriguez, J. Gonzalo,Tejedor, J. Luis
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p. 7631 - 7640
(2007/10/03)
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- PARTIAL REDUCTION OF DINITROARENES TO NITROANILINES WITH HYDRAZINE HYDRATE.
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Dinitroarenes containing substituents such as hydroxyl and amine groups could be conveniently reduced with 3 molar equivalents of hydrazine hydrate in presence of Raney nickel catalyst in ethanol/1,2-dichloro-ethane solvent mixture to give a product wherein one of the two nitro groups was reduced to the amino group. The yields of the partial reduction products are good. Under similar conditions alkoxyl substitutes in the o,p-position to the nitro groups were displaced by the hydrazine to give 2,4-dinitrophenyl-hydrazine as the main product. The details of the reduction reaction are described.
- Avyyangar,Kalkote,Lugade,Nikrad,Sharma
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p. 3159 - 3164
(2007/10/02)
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