Indolo‐α‐pyrone und Indolo‐α‐pyridone

Plieninger, Hans; Müller, Wolfgang; Weinerth, Klaus

doi:10.1002/cber.19640970308

Cited by 63 publications

(27 citation statements)

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“…For the preparation of the N-unsubstituted parent compound 5, heating of 1a in formamide/formic acid was found to be the method of choice, affording 5 in 88% yield. Introduction of the desired basic side chain was accomplished by prolonged heating of the diester 1a with excess N,N-diethyl-1,3-analogous fashion, the mono-methyl-substituted carbazole-2,3-diester 1b 20 (lacking the methyl group at position 4) was smoothly cyclized into the imide 6b. …”

Section: Resultsmentioning

confidence: 99%

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Synthesis of tetra- and pentacyclic carbazole-fused imides as potential antitumor agents

Haider¹,

Jbara²,

Käferböck³

et al. 2009

Arkivoc

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Section: Resultsmentioning

confidence: 99%

“…]-4-methylpyrrolo[3,4-b]carbazole-1,3(2H,5H)-dione (6b). A solution of dimethyl 1-methyl-9H-carbazole-2,3-dicarboxylate (1b) 20 …”

Section: -[3-(diethylamino)propyl]-410-dimethylpyrrolo[34-b]carbazmentioning

confidence: 99%

Synthesis of tetra- and pentacyclic carbazole-fused imides as potential antitumor agents

Haider¹,

Jbara²,

Käferböck³

et al. 2009

Arkivoc

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“…The residue was recrystallized from ethyl acetate-light petroleum to afford 4d (342 mg, 88%) as light-brown crystals, mp 148-151 °C; 1 H-NMR δ 11.34 (1H, s, carbazole-NH), 9.14 (1H, br, urethane-NH), 8.11 (1H, d, J = 7.8 Hz, 5-H), 7.92 (1H, s, 4-H (6). A solution of the azide 3 (308 mg, 1 mmol) in dry toluene (10 mL) was refluxed for 15 min.…”

Section: Methyl 3-[(benzyloxycarbonyl)amino]-1-methyl-9h-carbazole-2-mentioning

confidence: 99%

“…Here, we report on the synthesis and transformations of these compounds, starting from the known diester 1 which can be easily prepared by Diels-Alder reaction of 4-methylpyrano [3,4-b]indol-3(9H)-one with dimethyl acetylene dicarboxylate. 6,7 …”

Section: Introductionmentioning

confidence: 99%

Convenient synthesis of new 3-aminocarbazole and pyrimido[5,4-b]carbazole derivatives

Fidesser¹,

Haider²,

Jbara³

2002

Arkivoc

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Regioselective hydrolysis of dimethyl 1-methyl-9H-carbazole-2,3-dicarboxylate permits functionalisation of the carbazole skeleton in position 3 by conversion of the carboxylic acid 2 thus obtained into the azide 3. Curtius degradation of the latter gives the amine 5, various urethane derivatives thereof (4), and the urea 6. Base-induced cyclization of 6 leads to the pyrimido[5,4-b]carbazole 7a, whereas an analogous compound bearing a basic side chain (7b) is formed by spontaneous cyclization of an intermediate urea.

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“…After some unsuccessful attempts with the corresponding anhydride, we employed the protected N-phenylimide (5) as the electrophile. This compound can be easily prepared starting from commercially available 1-methylpyrano [3,4-b]indol-3(9H)-one 20) (1) by Diels-Alder reaction with dimethyl acetylenedicarboxylate which gives the diester (2), 20,21) followed by ester hydrolysis and subsequent formation of the cyclic anhydride (3). 22) Heating of the latter with excess aniline, followed by protection of the carbazole nitrogen with a benzenesulfonyl group gives 5 in good overall yield.…”

Section: )mentioning

confidence: 99%

1,5-Dimethyl-6H-pyridazino[4,5-b]carbazole, a 3-Aza Bioisoster of the Antitumor Alkaloid Olivacine.

Haider

Sotelo

2002

CHEMICAL & PHARMACEUTICAL BULLETIN

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Olivacine (1,5-dimethyl-6H-pyrido[4,3-b]carbazole) is a member of the pyridocarbazole family of alkaloids. It was first isolated from the bark and stem of Aspidosperma olivaceum 2) and it has been found to possess similar antitumor activity as its 5,11-dimethyl isomer, ellipticine, and related compounds like 9-methoxyellipticine. 3,4) As the main mechanism of these agents' antineoplastic action, a stabilization of the "cleavable complex" which is formed between DNA and the enzyme, topoisomerase II,5) is generally accepted, although additional mechanisms have been discussed for some pyridocarbazoles, e.g. reactivation of the lost functionality of the p53 protein.6) Based on the naturally occurring lead compounds, numerous modifications of this system have been studied, 7) leading to the development of drugs like elliptinium, 8) datelliptium, 9) retelliptine, 10) or pazelliptine. 11)More recently, the highly potent olivacine analog, S16020-2, 12,13) has attracted considerable attention due to its apparent ability to circumvent P-glycoprotein-mediated multidrug resistance. 14)Among the structural variations which have been described so far, there are several examples for incorporation of an additional nitrogen atom into the tetracyclic skeleton, like in the case of 9-aza-ellipticine 15) or pazelliptine. 11,16) Based on previous investigations in the 3-aza-ellipticine series by Landelle et al.,17) we recently reported the synthesis of several pyridazino [4,5-b]carbazoles, some of which exhibited significant antitumor activity.18) In the course of our ongoing research in this field, we now became interested in the synthesis of the hitherto unknown title molecule, 1,5-dimethyl-6H-pyridazino [4,5-b]carbazole, as a 3-aza isoster of olivacine, which was required as a reference compound. Until now, only one method for the preparation of 1,5-dialkyl-6H-pyridazino[4,5-b]carbazoles has been described, which is based on a ring transformation of 5-acyl-11H-pyrido [4,3-a]carbazoles under Wolff-Kishner conditions. 19) However, this sequence inherently leads to 5-ethyl-substituted pyridazino [4,5-b]carbazoles and thus cannot be adopted to the synthesis of our target structure. Here, we wish to report on a short synthesis of 3-aza-olivacine and on the results of an initial in-vitro testing for antitumor activity.In a first approach to the 1,5-disubstituted pyridazino [4,5-b]carbazole skeleton, we investigated the selective addition of methyllithium to an appropriate 1-methylcarbazole-2,3-dicarboxylic acid derivative. After some unsuccessful attempts with the corresponding anhydride, we employed the protected N-phenylimide (5) as the electrophile. This compound can be easily prepared starting from commercially available 1-methylpyrano[3,4-b]indol-3(9H)-one 20) (1) by Diels-Alder reaction with dimethyl acetylenedicarboxylate which gives the diester (2), 20,21) followed by ester hydrolysis and subsequent formation of the cyclic anhydride (3). 22) Heating of the latter with excess aniline, followed by protection of the carbazole nitr...

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Indolo‐α‐pyrone und Indolo‐α‐pyridone

Cited by 63 publications

References 1 publication

Synthesis of tetra- and pentacyclic carbazole-fused imides as potential antitumor agents

Synthesis of tetra- and pentacyclic carbazole-fused imides as potential antitumor agents

Convenient synthesis of new 3-aminocarbazole and pyrimido[5,4-b]carbazole derivatives

1,5-Dimethyl-6H-pyridazino[4,5-b]carbazole, a 3-Aza Bioisoster of the Antitumor Alkaloid Olivacine.

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