synthesis and catalytic functionalization of biologically active indoles

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1 Palladium-catalyzed Coupling Reactions of Indoles 61 Br OTBDMS Pd(OAc) 2 (1 mol%) ligand I (2 mol%) LiHMDS (1.3 equiv) N Me R toluene, 100 °C, 24 h Me 1R2 1 2 R RN OTBDMS NH N Me 190 191a-j Me N P H N OTBDMS H N OTBDMS H N Me Me N N 191a (85%) Me Me 191b (40%) 191c N ligand I H N OTBDMS Me H N 191d (60%) N Me F 191e (91%) Me N Me OTBDMS N Me Me (85%) OTBDMS N OTBDMS N OTBDMS O N OTBDMS 191f Me N Me (50%) Me N 191g Me (75%) N Me Me 191h (55%) N OTBDMS H N OTBDMS N Me N Me Me 191i (73%) 191j (91%) Me Scheme 49. Palladium-catalyzed amination of 3-silyloxy-5-bromo-2-methylindole. Very active catalysts for Buchwald-Hartwig amination have been devised not only for aryl bromides but also for the less reactive aryl chlorides or sulfonates. [138] In addition, the reaction has been extended to many NH-containing species other than amines such as amides, lactams, ureas, and hydrazines etc.. Hess and Kirsch examined Buchwald-Hartwig amination of �-chloroacrolein by lactams and heteroarylamines. [139] Vinyl chlorides [140] were scarcely studied and to investigate their reactivity in cross-coupling amination is an interesting application. Following Scheme 50 pictured the palladium-catalyzed Buchwald-Hartwig amination of �- chloroacrolein with indole.
1 Palladium-catalyzed Coupling Reactions of Indoles 62 Cl CHOH N H Pd(OAc) 2/Xantphos (6 mol%) Cs 2CO 3 (1.2 equiv) toluene, 85 °C, 20 h 192 193 1 Scheme 50. Amination of �-chloroacrolein by indole. N (54%) Reacting indole 1 with �-chloroacrolein 192 in the presence of Pd(OAc)2/Xantphos and Cs2CO3 gave 193 in 54% yield. Several NH-containing species were studied in the C-N coupling in this paper and led to the desired coupling products. There is still a continuing interest in the improvement of new catalyst systems for aryl chlorides as well as for sulfonates. Recent efforts in this area have focused on the development of more active catalysts that operate at lower catalyst loadings and with shorter reaction times. Buchwald and co-workers developed an expedited palladium-catalyzed amination of aryl nonaflates through the use of microwave-irradiation and soluble organic amine bases. [141] C-N Bond forming reactions using microwave irradiation mostly employed highly polar solvents and strong bases. [142] Consequently, base sensitive functional groups were not tolerated and limited the use and application. Soluble organic amine should improve the functional group tolerance and provided more efficient heating and stirring in microwave-assisted palladium-catalyzed amination reaction with aryl nonaflates. Scheme 51 pictured one selective example of indole nonaflate with aniline. NfO NH2 Pd2(dba) 3 (2.5 mol%) ligand J (10 mol%) DBU (2.5 equiv) H N N toluene, 150 °C, 30 min 194 Me microwave irradiation 195 Nf = OSO 2(CF 2) 3CF 3 iPr iPr ligand J PtBu 2 Scheme 51. Palladium-catalyzed amination of indole nonaflates. iPr (99%) CHO N Me
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Leibniz-Institut für Katalyse e. V
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Für meine Eltern Siegfried und Ker
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Mein besonderer Dank gilt Dr. Anneg
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Table of Contents Preface .........
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List of Abbreviations Ac Acetyl aq
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Preface The search for drugs is an
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1 Palladium-catalyzed Coupling Reac
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mixture was used for the synthesis
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7.11 (ddd, 1H, J = 8.0 Hz, J = 7.0
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FULL PAPER DOI: 10.1002/ejoc.200800
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Synthesis of Potential 5-HT 6 Recep
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FULL PAPER DOI: 10.1002/ejoc.200700
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Synthesis of Indole-2,3-dicarboxyla
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3 Publications 132 3.8 Selective Re
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8 7 N R N R OH CO2Et CO2Et OH indol
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mixture was stirred at 78 C for 3 m
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3.89 (s, 2H, H-10), 4.27 (s, 2H, H-
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DOI: 10.1002/cssc.200700160 General
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Zn-Catalyzed Hydroamination of Term
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Zn-Catalyzed Hydroamination of Term
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3 Publications 146 3.10 Zn-Catalyze
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Over the past years, we investigate
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3 Publications 150 3.11 First Synth
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4608 K. Alex et al. / Tetrahedron L
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Publikationen 1 Titanium-Catalyzed
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