Synthesis of 3-amino derivatives of benzo[b]furo[2,3-c]pyridines

Толкунов, С. В.; Kal'nitskii, M. N.; Zemskaya, E. A.

doi:10.1007/bf00471756

Cited by 10 publications

(6 citation statements)

References 6 publications

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“…3-Dimethylamino-1-methylindolo[2,3-c]pyrilium Perchlorate (10a) was obtained according to our reported method [19] by the cyclization of the dimethylamide of 2-acetyl-3-indolylacetic acid [18].…”

Section: -Acetylamino-1-methylindolo[23-c]pyridin-3(2h)-one (9b)mentioning

confidence: 99%

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Heterocyclization of 2-acyl-3-indolylacetic acids using hydrazine. Synthesis of 2,3-dihydro-2-oxo-5-R1-1H-[1,2]diazepino[4,5-b]indoles

Толкунов

Eresko

Khizhan

et al. 2009

Chem Heterocycl Comp

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Keywords: 2-aminoindolo[2,3-c]pyridin-3(2H)-one, hydrazine hydrate, hydrazones of 2-acetyl-3-indolylacetic acid, 2,3-dihydro-2-oxo-5-R 1 -1H-[1,2]diazepino [4,5-b]indoles.Interest in derivatives of 2,3-benzodiazepines is related to the broad spectrum of their biological action on the central nervous system [1][2][3][4][5][6][7]. Some 2,3-benzodiazepines have been found to be tranquilizers and anticonvulsants [2][3][4]. The tranquilizer, Tofizopam, a 2,3-benzodiazepine, has found use in clinical practice [1]. Considerable attention has been given to the synthesis and study of the pharmacological properties of diazepines condensed with various heterocyclic systems [3,4,6].A number of pathways have been reported for the synthesis of derivatives of 2,3-benzo-4-diazepinones based on the reaction of 2-aroyl-4,5-dimethoxyphenylacetic acids with hydrazine [2,[8][9][10]. 3H-[1,2]Diazepino [5,6-b]indoles were obtained by the cyclization of the ethyl esters of 2-formyl-and 2-acetyl-2-indolylacetic acids using hydrazine hydrate [11][12][13].We have recently shown that the reaction of 2-acetylbenzo[b]furan-3-acetic acid as well as its ester and amide derivatives with hydrazine hydrate leads not to the corresponding benzofurodiazepines but rather to 2-aminobenzofuro[2,3-c]pyridin-3(2H)-ones or azines of 2-acetylbenzo[b]furan-3-acetic acid [14].

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Section: -Acetylamino-1-methylindolo[23-c]pyridin-3(2h)-one (9b)mentioning

confidence: 99%

“…was obtained according to our reported procedure [19] by the cyclization of the morpholide of 2-propionylindolyl-3-acetic acid [18].…”

Section: -Acetylamino-1-methylindolo[23-c]pyridin-3(2h)-one (9b)mentioning

confidence: 99%

Heterocyclization of 2-acyl-3-indolylacetic acids using hydrazine. Synthesis of 2,3-dihydro-2-oxo-5-R1-1H-[1,2]diazepino[4,5-b]indoles

Толкунов

Eresko

Khizhan

et al. 2009

Chem Heterocycl Comp

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“…We found significant differences between the properties of compounds 1-3 and the properties of analogously constructed 1,3-dialkyland 1-alkyl-3-aryl-substituted pyrylium salts [1,2,15]. Compound 11 is identical to the sample obtained from 1-methyl-3-hydroxybenzofuro[2,3-c]pyrylium borofluoride (according to TLC and 1 H NMR [4]). When perchlorates 1b,d and 2b were boiled with ammonium acetate in acetic acid, in each case two products were isolated: from salt 1b we obtained 1,7-dimethyl-2-(4-methylphenylamino)benzofuro[2,3-c]pyridin-3(2H)-one (10a) (64%) and 1,7-dimethylbenzofuro[2,3-c]pyridin-3(2H)-one (11) (36%); from salt 1d we obtained 2-(4-bromophenyl)-1,7-dimethylbenzofuro[2,3-c]pyridin-3(2H)-one (10b) (60%) and pyridinone 11 (40%); from salt 2b we obtained 1,6-dimethyl-2-(4-methylphenyl)(benzothieno[2,3-c]pyridin-3(2H)-one (12) (55%) and 1,6-dimethylbenzothieno[2,3-c]pyridin-3(2H)-one (13) (45%).…”

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Reaction of 3-Arylaminobenzofuro-, 3-Arylaminobenzothieno-, and 3-Arylaminoindolo[2,3-c]pyrylium Salts with Nucleophilic Reagents

Толкунов

Vysotsky

Gorban

et al. 2005

Chem Heterocycl Compd

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Pyrylium salts are interesting systems for studying reaction with nucleophilic reagents [1, 2]. The functional groups in the cation affect the electronic structure and consequently the chemical properties of these salts, and participate in ring formation processes [3,4]. In continuing research on synthesis and conversions of condensed pyrylium salts [5, 6], we have studied the reactions of 3-arylaminobenzofuro-(1), 3-arylaminobenzothieno-(2), and 3-arylaminoindolo[2,3-c]pyrylium (3) perchlorates with nucleophilic reagents. With the aim of determining the effect of the arylamino group on the reactivity of the pyrylium ring condensed with different benzannelated heterocycles, we have calculated the electronic structure parameters of salts 1a-3a within the coupled multiparameter perturbation theory of the PPP method [7,8]. The parameters of the π-electron Hamiltonian and the resonance integrals are analogous to those assumed for the carbon and nitrogen atoms [9, 10] and the oxygen atom of the furan ring [11], and the thiophene sulfur atom in [12]. The effect of substituents on the electronic structure parameters of the compounds was taken into account within perturbation theory describing chemical substitution [13].Based on analysis of the electronic structure parameters of the cations for salts 1a-3a, we showed that charge localization is observed mainly in the pyrylium ring and on the hetero atoms O, N, and it decreases somewhat as we go to the corresponding anhydro forms of these compounds 4a-6a.

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“…Thus, various methods have been applied for their preparation 5,8. The most common (classical organic) methods for the synthesis of N ‐substituted 2‐aminopyridines include N ‐alkylation of 2‐aminopyridines,8a reactions of aliphatic amines with 2‐halopyridines, pyridinium salts or with imidol silyl ethers derived from the corresponding pyridin‐2‐ones,8g–i aminolysis of 2‐alkoxypyridines,8i,j reactions of α,β‐unsaturated ketones with cyano derivatives and amines,8l, or reactions of 2‐alkoxypyridines with amines in the presence of Et 2 AlCl 8m. Other, more recent strategies include transition metal‐catalyzed reactions,8n such as the Buchwald–Hartwig amination of 2‐halopyridines,8p which complement the classical synthetic approaches.…”

Section: Introductionmentioning

confidence: 99%

Access to 2‐Aminopyridines – Compounds of Great Biological and Chemical Significance

2011

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2-Aminopyridines are key structural cores of bioactive natural products, medicinally important compounds, and organic materials and thus, extremely valuable synthetic targets. The few reported 6-substituted 2-aminopyridines and the lack of flexible, efficient and general applicable methods for their synthesis demonstrates the urgent need of new methods for their preparation. Reactions between 2,6-dibromopyridine and primary or secondary, cyclic or acyclic, and aliphatic or aromatic amines were shown to selectively yield the respective 6-bromopyridine-2-amines in very high yields which were successfully used as substrates for subsequent C À C cross-coupling reactions. The recently introduced dichloro-bis[1-(dicyclohexylphosphanyl)piperidine]palladium (1) was used as catalyst for the cross-coupling of 6-bromopyridine-2-amines with arylboronic acids, diaryl-and dialkylzinc reagents or olefins and hence, is also an excellent C À C cross-coupling catalyst for this type of substrate. Moreover, all the reaction protocols presented were in each of the catalyses uniformly applied. The scope of both the amination and the cross-coupling reactions are well defined and allow one to simply adapt the reaction protocols directly to other amines and/or coupling partners and, thus, provide for the first time a very flexible and generally applicable reaction protocol to get access to 2-aminopyridines.

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Synthesis of 3-amino derivatives of benzo[b]furo[2,3-c]pyridines

Cited by 10 publications

References 6 publications

Heterocyclization of 2-acyl-3-indolylacetic acids using hydrazine. Synthesis of 2,3-dihydro-2-oxo-5-R1-1H-[1,2]diazepino[4,5-b]indoles

Heterocyclization of 2-acyl-3-indolylacetic acids using hydrazine. Synthesis of 2,3-dihydro-2-oxo-5-R1-1H-[1,2]diazepino[4,5-b]indoles

Reaction of 3-Arylaminobenzofuro-, 3-Arylaminobenzothieno-, and 3-Arylaminoindolo[2,3-c]pyrylium Salts with Nucleophilic Reagents

Access to 2‐Aminopyridines – Compounds of Great Biological and Chemical Significance

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