Compared Reactivity of Heterocyclic Enaminones:  Photochemical and Palladium Catalyzed Synthesis of 6,7,8,9-Tetrahydro-5<i>H</i>-pyrido[3,2-<i>b</i>]indol-9-ones

Blache, Yves; Sinibaldi-Troin, Marie-Eve; Voldoire, Aline; Chavignon, Olivier; Gramain, Jean-Claude; Teulade, Jean‐Claude; Chapat, Jean‐Pierre

doi:10.1021/jo970637+

Cited by 29 publications

(10 citation statements)

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“…23 Compound 39 which was prepared from a 1,3-diketone was subjected to Pd(PPh 3 ) 4 and NaHCO 3 in HMPA at 140 uC to provide corresponding azaindoles (40) in moderate yields. The application of Heck-type reactions to the construction of the azaindole framework was briefly investigated by Blache and co-workers in 1997 (Scheme 15).…”

Section: Azaindole Formation Viamentioning

confidence: 99%

Organometallic methods for the synthesis and functionalization of azaindoles

et al. 2007

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Azaindoles (also called pyrrolopyridines) constitute essential subunits in many pharmaceutically important compounds. The synthesis of azaindoles has been a great synthetic challenge for chemists. Many classical methods for indole synthesis (such as Fischer and Madelung cyclizations) often cannot be effectively applied to the synthesis of the corresponding azaindoles. In recent years, advances in organometallic chemistry have enabled a number of novel and efficient methodologies for azaindole formation as well as for the further functionalization of azaindole templates. In this tutorial review, we have surveyed the recent development of organometallic chemistry-based methods for azaindole synthesis.

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Section: Azaindole Formation Viamentioning

confidence: 99%

Organometallic methods for the synthesis and functionalization of azaindoles

et al. 2007

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“…According to previously described procedures, 22,23,25,26) the secondary enaminone 7 is obtained by condensation of 3-aminoquinoline 5 and 1,3-cyclohexandione 6 in toluene with catalytic amounts of p-toluenesulfonic acid. Then, a methyl or a diethylaminoethyl side chain was introduced on the enaminone nitrogen by treating secondary enaminone 7 by sodium hydride, and then by methyl iodide or by the hydrochloride salt of diethylaminoethylchloride to give 8 and 9.…”

Section: Chemistrymentioning

confidence: 99%

“…Enaminones represent convenient tools in heterocyclic chemistry since they can be implicated in the elaboration of carbazoles, 20) a-carbolines, 21) b-carbolines and dcarbolines. 22,23) The photocyclization can occur through an electrocyclization for tertiary enaminones or through a radical process for halogenated enaminones. 24) Furthermore, in our recent works, we obtained N-benzylpyridocarbazoles and indoloquinolines from tertiary N-benzylenaminones 25) and non N-substituted compounds from secondary iodinated enaminones.…”

mentioning

confidence: 99%

Synthesis and Biological Evaluation of Indoloquinolines and Pyridocarbazoles: A New Example of Unexpected Photoreduction Accompanying Photocyclization

Aragon

Yapi

Pinguet

et al. 2007

CHEMICAL & PHARMACEUTICAL BULLETIN

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Interest in the chemistry of pyridocarbazoles and indoloquinolines has increased this last decade since these skeletons are present in a large number of alkaloids of biological interest. For example, the indoloquinoline type alkaloid cryptolepine 1 (Fig. 1) extracted from the roots of Cryptolepis sanguinolenta 1) has been shown to exhibit antiplasmodial, 2) antibacterial 3) and cytotoxic properties. 4,5) This last activity is due to cryptolepine intercalation into DNA and subsequent inhibition of DNA religation by topoisomerase II. 5) Another example concerns the pyridocarbazole type alkaloid ellipticine 2 (Fig. 1) extracted from the leaves of Ochrosia elliptica 6) which has exhibited cytotoxic properties by different mechanisms : intercalation into DNA, 7) inhibition of topoisomerase II,8) formation of covalent adducts with DNA after bioactivation, 9) stimulation of apoptosis. 10) Different linear and angular analogs of these compounds have already been synthetized by several groups [11][12][13][14][15][16][17] but the series of indolo [2,3-c]quinoline and pyrido [2,3-c]carbazole haven't been studied yet.Therefore, as a part of our program concerning the elaboration of analogs of natural products, we are interested in the chemistry as well as in the biological activities of these angular heterocycles. 18,19) Our methodology resides in the photocyclization of enaminones derived from 3 or 6-aminoquinoline ( Fig. 1). Enaminones represent convenient tools in heterocyclic chemistry since they can be implicated in the elaboration of carbazoles, 20) a-carbolines, 21) b-carbolines and dcarbolines.22,23) The photocyclization can occur through an electrocyclization for tertiary enaminones or through a radical process for halogenated enaminones.24) Furthermore, in our recent works, we obtained N-benzylpyridocarbazoles and indoloquinolines from tertiary N-benzylenaminones 25) and non N-substituted compounds from secondary iodinated enaminones. 26) In the present work, we investigate the reactivity of tertiary enaminones carrying an alkyl or a dialkylaminoalkyl side chain 3 and report the results of in vitro cytotoxicity studies of the obtained cyclized compounds 4. ChemistryFirtsly, the reactivity of tertiary enaminones derived from 3-aminoquinoline was studied. According to previously described procedures, 22,23,25,26) the secondary enaminone 7 is obtained by condensation of 3-aminoquinoline 5 and 1,3-cyclohexandione 6 in toluene with catalytic amounts of p-toluenesulfonic acid. Then, a methyl or a diethylaminoethyl side chain was introduced on the enaminone nitrogen by treating secondary enaminone 7 by sodium hydride, and then by methyl iodide or by the hydrochloride salt of diethylaminoethylchloride to give 8 and 9. The dimethylaminopropyl side chain couldn't be introduced following this protocole. However, the tertiary enaminone 10 was obtained by treating compound 7 with the hydrochloride salt of dimethylaminopropylchloride in presence of sodium hydride in dimethylformamide (DMF) 27) (Fig. 2). The methyl substituent w...

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“…Use of the double N-arylation strategy to synthesize multi-substituted carbazoles (93) The synthesis of 1,2,3,4-tetrahydro-4-oxo-β-carboline (110) from bromoenaminones (109) via palladium-catalyzed intramolecular cyclization using tetrakis[triphenylphosphine] palladium was described by Chen et al [97], and the same kind of palladium-assisted cyclization of chloroenaminones was reported by Blache et al [98]. Aoyagi et al [100] developed an efficient method for the preparation of indoles 112A-C utilizing the palladium-catalyzed oxidation methodology of Yoshida and Tamaru [99].…”

Section: Synthesis Of Indolinesmentioning

confidence: 99%

Recent Uses of Palladium Chemistry in Indole Synthesis

Buolamwini¹

2006

COS

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Compared Reactivity of Heterocyclic Enaminones: Photochemical and Palladium Catalyzed Synthesis of 6,7,8,9-Tetrahydro-5H-pyrido[3,2-b]indol-9-ones

Cited by 29 publications

References 21 publications

Organometallic methods for the synthesis and functionalization of azaindoles

Organometallic methods for the synthesis and functionalization of azaindoles

Synthesis and Biological Evaluation of Indoloquinolines and Pyridocarbazoles: A New Example of Unexpected Photoreduction Accompanying Photocyclization

Recent Uses of Palladium Chemistry in Indole Synthesis

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