- Synthesis of new fused and substituted benzo and pyrido carbazoles via C-2 (het)arylindoles
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In the course of a program aimed at designing new antitumor agents, we were interested in the synthesis of new substituted benzo and pyrido carbazoles. The synthesis was performed through an efficient four-step sequence from a 2-trimethylstannylindole derivative and via C-2 (het)arylindoles. The synthetic sequence was developed using two palladium mediated reactions including, at the end of the synthesis, a direct (het)arylannulation, which led to the desired heterocycles.
- Bourderioux, Aurélie,Kassis, Paméla,Mérour, Jean-Yves,Routier, Sylvain
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experimental part
p. 11012 - 11019
(2009/04/11)
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- Total synthesis of new indolo[2,3-a]quinolizine alkaloids sempervirine type, potential pharmaceuticals
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Total synthesis of the two series of new pentacycilc cycloalk[g]indolo[2,3-a]quinolizine alkaloids (modified sempervirine possessing the wide range of activity), has been elaborated in five steps from 5-acetyl-3-methylthio-1,2,4-triazine (obtained from the simple acyclic materials). In the two key steps: inverse electron demand Diels-Alder reaction of precursor with cyclic enamines and the following Fischer indolization of 3-acetyl-1-methylthiocycloalka[c]pyridines, the AB-DE synthons, has been obtained. The final stages: desulfuration, and formation of the C-ring via the Gribble method have led to the expected zwitterionic alkaloids. Model syntheses of the indolopyridocoline and its methoxy analogue from 2-acetylpyridine have been performed for investigation of the microwave-induced Fischer synthesis of sensitive indoles and for obtaining compounds for comparative study of spectroscopic data.
- Lipińska, Teodozja M.
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p. 5736 - 5747
(2007/10/03)
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- Syntheses, structures, and electroluminescence of new blue/green luminescent chelate compounds: Zn(2-py-in)2(THF), BPh2(2-py-in), Be(2-py- in)2, and BPh2(2-py-aza) [2-py-in = 2-(2-pyridyl)indole; 2-py-aza = 2-(2
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Four novel blue/green luminescent compounds, Zn(2-py-in)2(THF) (1), BPh2(2-py-in) (2), Be(2-py-in)2 (3), and BPh2(2-py-aza) (4), where 2-py-in = 2-(2-pyridyl)indole and 2-py-aza = 2-(2-pyridyl)-7-azaindole, have
- Liu, Shi-Feng,Wu, Qingguo,Schmider, Hartmut L.,Aziz, Hany,Hu, Nan-Xing,Popovic, Zoran,Wang, Suning
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p. 3671 - 3678
(2007/10/03)
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- Palladium(0)-catalyzed heteroarylation of 2- and 3-indolylzinc derivatives. An efficient general method for the preparation of (2-pyridyl)indoles and their application to indole alkaloid synthesis
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Palladium(0)-catalyzed coupling of (1-(benzenesulfonyl)-2-indolyl)zinc chloride (1) and (1-(tert-butyldimethylsilyl)-3-indolyl)zinc chloride (6) with diversely substituted (alkyl, methoxy, methoxycarbonyl, nitro, hydroxy) 2-halopyridines gives the corresponding 2- and 3-(2-pyridyl)indoles [4 and 7 (or 8), respectively] in excellent yields. A series of other 3-(heteroaryl)indoles (pyrazinyl, furyl, thienyl, indolyl) have been similarly prepared from 6. The potential of some of these (2-pyridyl)indoles in alkaloid synthesis is demonstrated. Thus, from 2-(2-pyridyl)indole 4b, a new synthetic entry to the indolo[2,3-a]quinolizidine system, involving stereoselective hydrogenation of the pyridine ring with subsequent electrophilic cyclization upon the indole 3-position from an appropriately N(b)-substituted 2-(2-piperidyl)indole, is reported. For this purpose, Pummerer cyclizations have been extensively studied. Whereas the indole-unprotected sulfoxide 17 gives the corresponding indoloquinolizidine 19 in low yield and mainly undergoes an abnormal Pummerer cyclization that ultimately leads to sulfide 18, the N(a)-protected sulfoxides 24a and 24b afford the respective indoloquinolizidines 25a,b in 70% yield. On the other hand, the conversion of 3-(2-pyridyl)indole 8k into tetracyclic ketone 35 by stereoselective hydrogenation, followed by cyclization of the resulting all-cis-3-(2-piperidyl)indole 34, represents a formal synthesis of Strychnos alkaloids with the strychnan skeletal type (tubifoline, tubifolidine, 19,20-dihydroakuammicine). A similar conversion of 8j into nordasycarpidone constitutes a formal synthesis of the alkaloids of the uleine group. Reduction of nordasycarpidone leads to tetracycle 37, an advanced intermediate in a previous synthesis of tubotaiwine, a Strychnos alkaloid with the aspidospermatan skeletal type. Finally, piperidylindole 34 was transformed into tetracycle 41, an ABDE substructure of akuammiline alkaloids, by a sequence involving the skeletal rearrangement of an intermediate spiroindolenine as the crucial step.
- Amat, Mercedes,Hadida, Sabine,Pshenichnyi, Grigorii,Bosch, Joan
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p. 3158 - 3175
(2007/10/03)
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- Preparation and palladium-catalysed arylation of indolylzinc halides
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Indolylzinc halides are prepared by two methods: transmetallation of indolyllithiums with zinc chloride and oxidative addition of active zinc to iodoindoles. The palladium-catalysed reaction of the indolylzinc halides provides a practical method for synthesizing arylindoles.
- Sakamoto, Takao,Kondo, Yoshinori,Takazawa, Nobuo,Yamanaka, Hiroshi
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p. 1927 - 1934
(2007/10/03)
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- An Efficient Synthesis of 2-(2-Pyridyl)indoles by Palladium(0)-catalyzed Heteroarylation
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A general method for the preparation of 2-(2-pyridyl)indoles based on the palladium(0)-catalyzed coupling of 1-(benzenesulfonyl)-2-indolylzinc chloride with 2-halopyridines is reported.
- Amat, Mercedes,Hadida, Sabine,Bosch, Joan
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p. 5005 - 5006
(2007/10/02)
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- Indolylzinc iodides by oxidative addition of active zinc to iodoindoles
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Indolylzinc derivatives were prepared by the oxidative addition of active zinc to iodoindoles, which coupled with aromatic halides in the presence of palladium catalyst to give arylated indoles.
- Sakamoto, Takao,Kondo, Yoshinori,Takazawa, Nobuo,Yamanaka, Hiroshi
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p. 5955 - 5956
(2007/10/02)
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- A DIRECTED METALATION ROUTE TO THE ZWITTERIONIC INDOLE ALKALOIDS. SYNTHESES OF INDOLOQUINOLIZINE, FLAVOPEREIRINE, FLAVOCARPINE, AND DIHYDROFLAVOPEREIRINE
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A protocol involving beta-lithiation of 2-(2-pyridinyl)indoles (4->5) and subsequent reaction with bromoacetaldehyde or oxirane has led to syntheses of the alkaloids indoloquinolizine (1), flavopereirine (2), flavocarpine (21), and dihydroflavopere
- Gribble, Gordon W.,Johnson, David A.
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p. 5259 - 5262
(2007/10/02)
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