- Convenient One-Pot Synthesis of 9 H -Carbazoles by Microwave Irradiation Employing a Green Palladium-Based Nanocatalyst
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An efficient palladium-catalyzed tandem reaction for the one-pot synthesis of 9 H -carbazoles under microwave irradiation is developed. This approach involves a sequential Buchwald-Hartwig amination and a direct arylation from affordable and inexpensive anilines and 1,2-dihaloarenes. For the development of this purpose, a novel and magnetically recoverable palladium nanocatalyst supported on a green biochar under ligand-free conditions is used. Compared to other existing palladium-based protocols, the present synthetic methodology shows a drastic reduction in reaction times and excellent compatibility with different functional groups allowing to obtain a small library of 9 H -carbazoles in high yields and with good regioselectivity. This procedure represents the first example in the direct synthesis of carbazoles using a heterogeneous palladium nanocatalyst from commercial precursors. To examine the application of this protocol, a direct and scalable synthesis of the bioactive carbazole alkaloid clausenalene from commercially available starting materials is described.
- Steingruber, H. Sebastián,Mendioroz, Pamela,Volpe, María A.,Gerbino, Darío C.
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p. 4048 - 4058
(2021/08/03)
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- Preparation and Molecular Structures of 9,10-Dihydrophenanthrenes: Substituent Effects on the Long Bond Length
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9,10-Dihydrophenanthrene derivatives 1-3 with electron-donating and/or -accepting groups at their 9,10-positions were prepared, and their precise molecular structures were determined by X-ray analyses at 203 K. The long C9-C10 bond [1.646(4) A] in the hexaarylethane-type compound 1 with four electron-donating groups is mainly caused by steric interaction. Push-pull type substitution does not induce the elongation of the central bond in the present system; the corresponding distance in 9,9-bis(4-dimethylaminophenyl)-10,10-dicyano derivative 2 [1.599(4) A] is intermediate between those of 1 and the tetracyano compound 3 [1.587(2) A].
- Suzuki, Takanori,Ono, Kazunori,Nishida, Jun-Ichi,Takahashi, Hyou,Tsuji, Takashi
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p. 4944 - 4948
(2007/10/03)
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- Nucleophilic substitution in dibenz[b,d]iodolium and 11,12-dihydro-10H-dibenz[b,g]iodocinium cations
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Treatment of dibenz[b,d]iodolium tetrafluoroborate with NO2-, Br-, and N3- ions gave, along with nucleophilic substitution products, 2-nitro-, 2-bromo-, and 2-azido-2′-iodiphenyls, diphenyl, 2-iododiphenyl, and 2,2′-diiododiphenyl (products of one electron reduction), whereas 11,12-dihydro-10H-dibenz[b,g]-iododnium tetrafluoroborate underwent nucleophilic substitution with all three nucleophiles to give a single product in each case: 1-(2-nitrophenyl)-, 1-(2-bromophenyl)-, or 1-(2-azidophenyl)-3-(2-iodophenyl)propane. 1998 Plenum Publishing Corporation.
- Vanchikov,Bobyleva,Komissarova,Kulikov,Tolstaya
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p. 371 - 377
(2007/10/03)
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