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81.
The addition of secondary and primary amines to ethyl (1-amino-9,10-anthraquinon-2-yl)propynoate affords an easily separable
mixture of the corresponding ethyl 3-dialkylaminoor 3-alkylamino-3-(1-amino-9,10-anthraquinon-2-yl)acrylate and 3-dialkylamino-
or 3-alkylaminonaphthol[2,3-h]quinoline-2(1H), 7,12-trione (in ∼4: 1 ratio). Intramolecular cyclization of the resulting substituted ethyl acrylates results in the formation
of 4-dialkylaminoor 4-alkylamino-2-chlorinated pyridine rings. Subsequent nucleophilic substitution of the chlorine atom gives
2-functionalized 4-dialkylamino- or 4-alkylaminonaphtho[2,3-h]quinoline-7,12-diones.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2327–2332, November, 1998. 相似文献
82.
Andrew Mitchinson Wesley P. Blackaby Sylvie Bourrain Robert W. Carling Richard T. Lewis 《Tetrahedron letters》2006,47(13):2257-2260
Novel syntheses of 2,3,8-trisubstituted pyrido[2,3-d]pyridazines and 2,3,5-trisubstituted pyrazino[2,3-d]pyridazines are described. Two complementary routes to pyrido[2,3-d]pyridazines were developed, the first of which began by constructing the pyridine ring, and the second of which started by constructing the pyridazine ring. Pyrazino[2,3-d]pyridazines were prepared in a route employing an aza-Wadsworth-Emmons cyclization as the key step. The resulting compounds were found to be high affinity ligands for the GABAA receptor benzodiazepine binding site. 相似文献
83.
Anastacia A. Layeva Galina N. Lipunova Valerii N. Charushin 《Journal of fluorine chemistry》2007,128(7):748-754
A new approach for the synthesis of fluorinated 1H-quinazolin-4-ones and 4-substituted quinazolines has been developed. 6-Fluoro-1H-quinazolin-4-ones were obtained by intramolecular cyclization of fluorine-containing S-ethyl N-benzoylisothioureas. Nucleophilic substitution reactions at positions 2 and 7, as well as alkylation at 1-position of quinazolinones were investigated. In addition, the synthesis of fluorine-containing 4-aminoquinazolines was carried out. 相似文献
84.
Yu. B. Sinkevich A. E. Shchekotikhin Yu. N. Luzikov V. N. Buyanov L. V. Kovalenko 《Chemistry of Heterocyclic Compounds》2007,43(10):1252-1259
4,11-Dihydroxyanthra[2,3-b]thiophene-5,10-dione (thiophenoquinizarine) and its 3-methyl derivative were obtained by the cyclization
of quinizarin-2-yl derivatives of mercaptoacetaldehyde or mercaptoacetone in acid medium. 4,11-Dimethoxy-and 4,11-dibutoxyanthra[2,3-b]thiophene-5,10-dione
were synthesized by the alkylation of the hydroxyl group in the synthesized anthrathiophenes with dimethylformamide dimethylacetal
or butyl iodide respectively. Radical bromination of 4,11-dimethoxy-3-methylanthra[2,3-b]thiophene-5,10-dione, depending on
the amount of N-bromo-succinimide taken, leads to the formation of 3-bromomethyl-or 3-dibromomethyl-4,11-dimethoxy-anthra[2,3-b]thiophene-5,10-diones.
The action of sodium acetate on the obtained bromo derivatives with subsequent hydrolysis of the intermediate acetates led
to the synthesis of 3-hydroxymethyl-or 3-formyl-4,11-dimethoxy-anthra[2,3-b]thiophene-5,10-diones.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1478–1485, October, 2007. 相似文献
85.
Acylation of 4-α-furyl-4-N-benzylaminobut-1-enes with maleic anhydride gave 4-oxo-3-aza-10-oxatricyclo[5.2.1.01,5]dec-8-ene-6-carboxylic acid via amide formation followed by intramolecular Diels-Alder reaction of furan (IMDAF). The cycloaddition proceeded under mild reaction conditions (25 °C) and provided only the exo-adduct in quantitative yield. Treatment of this compound with PPA gave isoindolo[2,1-b][2]benzazepine derivatives via ring opening, aromatization and intramolecular electrophilic alkylation. In order to extend the scope of the reaction sequence, 7-oxo-5,11b,12,13-tetrahydro-7H-isoindolo[2,1-b][2]benzazepine-8-carboxylic acids were further transformed into useful synthetic intermediates. 相似文献
86.
87.
Toshikazu SaitohToshio Suzuki Norihiro OnoderaHideya Sekiguchi Hisahiro HagiwaraTakashi Hoshi 《Tetrahedron letters》2003,44(13):2709-2712
An efficient and versatile method for the stereospecific construction of α,ω-cis- and α,ω-trans-disubstituted eight- and nine-membered cyclic ethers was developed. Cyclization of the hydroxy epoxides promoted by Eu(fod)3 proceeded via an SN2 process and exo mode to provide the corresponding cyclic ethers in excellent yields. 相似文献
88.
Michael Klein 《Tetrahedron》2004,60(5):1087-1092
The synthesis of an enediyne sulfonamide by alkylidene carbene rearrangement is reported. The compound cyclizes thermally to give the Bergman product, which was prepared independently for comparison. Like other σ-acceptor substituents at the enediyne alkyne termini, such as fluoride, oxonium or ammonium groups, the sulfonamide moiety enhances the reactivity for thermal Bergman cyclization as shown by the cyclization kinetic of the title compound. 相似文献
89.
The oxidative cyclization of 5-(2-amino-5-methoxycarbonylphenyl)-substituted tricarbonyl[η4-cyclohexa-1,3-diene]iron complexes by air in protic medium provides the corresponding tricarbonyl[η4-4a,9a-dihydro-9H-carbazole]iron complexes. This procedure is applied to the total synthesis of the 3-methoxycarbonylcarbazole alkaloids mukonine and mukonidine. 相似文献
90.
Nicolas PhilippeFrançois Denivet Jean-Luc VasseJana Sopkova-de Olivera Santos Vincent Levacher Georges Dupas 《Tetrahedron》2003,59(40):8049-8056
The present report describes a stereoselective synthesis of 1,4-dihydro-4-phenyl isoquinolinones 5 based on a stereoselective Friedel-Crafts type cyclization. Cyclization precursors 1 were prepared in two steps, from the readily available (S)-mandelic acid, in 60-80% overall yield. The stereoselective electrophilic cyclization was accomplished in 20-86% yield and with 20-97% ee. In the course of this work, the presence of the amide carbonyl was found to be particularly important to guarantee a stereospecific process during the electrophilic aromatic substitution. 相似文献