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1.
New four-component domino reactions are described that allow the one-pot synthesis of spiro[indoline/acenaphthylene-3,4′-pyrazolo[3,4-b]pyridine derivatives from the reaction of phenylhydrazine, 3-aminocrotononitrile, isatin/acenaphthylene-1,2-dione, and cyclic 1,3-dicarbonyl compounds, including cyclohexane-1,3-diones, barbituric acid, and 2-thioxodihydropyrimidine-4,6(1H,5H)-dione, in the presence of (±)-camphor-10-sulfonic acid (CSA). These processes take place in water and involve the generation of two rings and five new bonds (two C-C, two C-N and one CN) in a single synthetic operation, with expedient work-up and diminished waste generation due to the absence of extraction and purification steps. 相似文献
2.
Cédric Kalinski Michael Umkehrer Nadine Jäger Wolfgang Hiller 《Tetrahedron letters》2006,47(12):2041-2044
A combinatorial synthetic route yielding fused tetrazolo[1,5-a]quinoxalines is described. The use of 2-fluorophenylisocyanide in the Ugi-tetrazole reaction (tetrazole-U-4CR) followed by a nucleophilic aromatic substitution (SNAr) affords the tricylic tetrazolo[1,5-a]quinoxaline moiety in good yields and with high diversity. 相似文献
3.
A new method was adopted for the synthesis of benzo[b]carbazoles by Claisen condensation followed by Fischer indole cyclization. Newly synthesized benzo[b]carbazoles were treated with ethanol amine in the presence of polyphosphoric acid which leads to the formation of pyrazino carbazoles. All the synthesized compounds were characterized by all spectral means. 相似文献
4.
Pushpak Mizar 《Tetrahedron letters》2009,50(25):3088-3231
The procedures described herein provide a facile method for the synthesis of pyrazolo[3,4-b]pyridine and pyrazolo[1,5-a]pyrimidine by reacting N-substituted or unsubstituted-pyrazol-5(4H)-one, aryl-oxoketene dithioacetals and alkyl amide. The products were obtained in moderate to good yield. The effects of the solvents and substitution have also been described. 相似文献
5.
Rakhi Pathak 《Tetrahedron》2006,62(12):2820-2830
Starting from simple indole precursors the synthesis of naphtho[a]carbazoles and benzo[c]carbazoles is described. Key steps include the use of the Suzuki-Miyaura reaction to afford 2- or 3-aryl substituted indoles, as well as a potassium t-butoxide and light assisted aromatic ring-forming reaction. 相似文献
6.
Eleni Dimitriadou Julia Stephanidou-Stephanatou Constantinos A. Tsoleridis Dimitra J. Hadjipavlou-Litina Christos Kontogiorgis George E. Kostakis 《Tetrahedron》2014
A new aspect concerning chromone chemistry leading to the one-pot synthesis of functionalized novel ABCD-fused chromenopyrazolopyridines has been described. The synthesis involves a multicomponent reaction of chromone-3-benzoylhydrazones with isocyanides and acetylenedicarboxylates, whereupon novel complex tetracyclic benzopyrone derivatives containing three stereogenic centres were formed. The structure elucidation of the products was accomplished by 1D and 2D NMR experiments and confirmed by X-ray crystallographic analysis. Full assignment of all 1H and 13C NMR chemical shifts has been unambiguously achieved. The reaction mechanism is also discussed. In addition, eight chromenopyrazolopyridine derivatives were tested for possible biological activity (antioxidant and lipid peroxidation inhibition). 相似文献
7.
Zsuzsanna Riedl Katrien Monsieurs Petra Dunkel Pál Tapolcsányi Sándor Boros Luc Pieters György Hajós 《Tetrahedron》2006,62(1):121-129
New synthetic pathways have been elaborated to 1-methyl-1H-pyridazino[3,4-b]indoles starting from halopyridazin-3(2H)-ones. Suzuki cross-coupling reaction of chloro, iodo, dichloro, and dibromo substituted pyridazin-3(2H)-ones with 2-pivaloylaminophenylboronic acid followed by hydrolysis of the amide and subsequent ring closure via condensation gave fused indoles. Some of these compounds showed biological activity as antitrypanosomal agents. 相似文献
8.
Witold M. BlochStephanie M. Derwent-Smith Fatiah IssaJonathan C. Morris Louis M. RendinaChristopher J. Sumby 《Tetrahedron》2011,67(48):9368-9375
The synthesis of six new compounds incorporating either a pyrazino[2,3-b]indolizine or indolizino[2,3-b]quinoxaline core are reported in good yield (58-87%). The intermediates for the key cyclization reaction for one set of compounds (5a-c), with a sterically demanding 3,5-dimethylpyrazole group in the 5-position of the core, were found to be mono-substituted. These intermediates could be isolated and cyclized by heating under acid-catalyzed conditions. To further demonstrate the versatility of the chemistry, compounds 6a-c were synthesized in 58-68% yields. Compounds 5a-c are non-planar in solution and the solid-state, while 6a-c have close to planar conformations, pointing to weak hydrogen bonds between the acidic C-Hs and the adjacent azine nitrogen atoms. The cytotoxicity of the six newly synthesized and three previously prepared compounds was assessed against a human glioblastoma multiforme cell line. 相似文献
9.
Gong LiXiaowei Wang Chao TianTongbo Zhang Zhili ZhangJunyi Liu 《Tetrahedron letters》2012,53(39):5193-5196
A novel pyrimido[4,5-b][1,4]diazepine-2,4,6-trione was synthesized with an efficient strategy. Especially, the key intermediate 2,4-dimethoxypyrimido[4,5-b][1,4]diazepin-6-one was promoted by one pot tandem reduction-cyclization with Na2S2O4. Subsequently, reduction of lactams 6 with LiAlH4 afforded a more flexible scaffold of pyrimidodiazepines. The synthetic strategy was versatile since it facilitated the sequential functionalization on the pyrimidodiazepine at three positions. Thus a convenient and effective method for the rapid preparing of multi-substituted pyrimido[4,5-b][1,4]diazepines was developed. 相似文献
10.
Ezhumalai YamunaMatthias Zeller Karnam Jayarampillai Rajendra Prasad 《Tetrahedron letters》2011,52(14):1649-1652
A one-pot procedure for the synthesis of highly substituted dihydrobenzo[a]carbazole derivatives via a regioselective cyclocondensation reaction between 2-(2,3,4,9-tetrahydro-carbazol-1-ylidene)-propanedinitrile and acetylenic esters is described. 相似文献
11.
A new efficient synthesis of indolo[3,2,1-jk]carbazoles by the palladium-catalyzed cyclization of N-(2-bromoaryl)carbazoles is described. The reaction involves intramolecular C-C bond formation, coupled with the cleavage of a C-X bond and a C-H bond on carbazole ring. Substitutions on N-aryl core with either electron-donating or electron-withdrawing groups are introduced, and different reaction factors for cyclization are evaluated. 相似文献
12.
Damien Hédou Emmanuel Deau Marine Harari Morgane Sanselme Corinne Fruit Thierry Besson 《Tetrahedron》2014
Reliable synthetic routes were studied for an access to a novel polyfunctionalized 6-amino-2-cyanobenzo[d]thiazole-5-carboxylate ester (1) and its analogue 5-amino-2-cyanothiazolo[5,4-b]pyridine-6-carboxylate ester (2). Both compounds 1 and 2 are functionalized as molecular bricks for the synthesis of innovative molecular systems. Part of the chemistry performed in this study was achieved under microwave irradiation. 相似文献
13.
Solid-phase synthesis of fused [2,1-b]quinazolinone alkaloids has been developed for the preparation of vasicinone and deoxyvasicinone by two approaches. The derivative of polymer-supported p-nitrophenyl carbonate was attached to anthranilic acid and then coupled with various bromo-lactams. This resin-linked bromo intermediate upon acetylation, hydrolysis and resin cleavage gave the cyclized [2,1-b]quinazolinones (vasicinone). Alternatively, resin-linked azido-benzoic acids were coupled with bromo-substituted lactams followed by cyclization in an aza-Wittig reductive cyclization process giving the bromo-substituted quinazolinone intermediates, with subsequent acetylation, hydrolysis and resin cleavage affording the fused [2,1-b]quinazolinones. 相似文献
14.
Larisa N YudinaJan Bergman 《Tetrahedron》2003,59(8):1265-1275
Double Fischer cyclisation was used to prepare indolo[3,2-b]carbazole and its 2,8-di-OMe, OH, Br and F-derivatives. N-monosubstituted derivatives of indolo[3,2-b]carbazole (methyl, hydroxymethyl, dimethylaminoethyl) were obtained starting from 5,11-di-Boc-indolo[3,2-b]carbazole. 相似文献
15.
We have developed a straightforward approach to diverse synthesis of 2,3-, 2,4-disubstituted pyrimido [1,2-a]benzimidazoles, 2,4,10-trisubstituted 2,10-dihydropyrimido [1,2-a]benzimidazoles and 2,3-disubstituted imidazo [2,1-b]benzothiazoles via multicomponent reactions (MCRs) of heterocyclic azoles, aldehydes with easily storable and handling alkynecarboxylic acids. In the presence of a catalytic amount of CuI and K2CO3, the pyrimido [1,2-a]benzimidazole or imidazo [2,1-b]benzothiazole scaffold could be rapidly constructed through a 6-endo-dig or 5-exo-dig cyclization, respectively. The preliminary mechanistic study suggested that the formation of 2,3- disubstituted pyrimido [1,2-a]benzimidazoles, which completes the assembly of the scaffold and its C-3 position functionalization in one pot, undergoes a novel cascade process involving a decarboxylation, A [3] coupling, 6-endo-dig cyclization, nucleophilic addition and dehydration. 相似文献
16.
Jairo Quiroga Jorge Trilleras Rodrigo Abonía Antonio Marchal 《Tetrahedron letters》2010,51(7):1107-402
Several pyrimido[4,5-b]quinolines, flavin analogues, have been prepared by assisted microwave intramolecular cyclization of N4-substituted-2,4-diamino-6-chloropyrimidine-5-carbaldehydes. The reaction takes place with hydrolysis of amino-group and chlorine. Particularly valuable features of this method included the broader substrate scope and operational simplicity as well as increased safety for small-scale high-speed synthesis. 相似文献
17.
Catherine Ball Olivier Lorthioir Lee W. Page Charlotte L. Smith Stephen P. Watson 《Tetrahedron letters》2010,51(30):3907-7524
An efficient one-pot microwave approach for the synthesis of novel [1,3]oxazolo[3,2-b][1,2,4]triazoles is described. 相似文献
18.
Takenari Nakagome Raymond N. Castle Hirotaka Murakami 《Journal of heterocyclic chemistry》1968,5(4):523-532
The Hofmann reaction on 6-methylpyridazine-3,4-dicarboxamide (1) gave a mixture of 3-methylpyrimido[4,5-c]pyridazine-5,7-dione (2), 3-methylpyrimido[5,4-c]pyridazine-6,8-dione (3) and an acid (4) of unknown structure. The Hofmann reaction on pyridazine-3,4-dicarboxamide (9) gave a mixture of pyrimido[4,5-c]pyridazine-5,7-dione ( 10 ) and an acid ( 11 ) of unknown structure. The reaction of 3-amino-6-methylpyridazine-4-carboxamide ( 18 ) with ethyl orthoformate gave 3-methylpyrimido[4,5-c]pyridazin-5-one ( 21 ). 4-Aminopyridazine-3-carboxamide ( 36 ) upon fusion with urea gave pyrimido[5,4-c]pyridazine-6,8-dione ( 37 ) while with ethyl orthoformate 36 gave pyrimido[5,4-c]pyridazin-8-one ( 38 ). Pyrimido[5,4-c]-pyridazine-8-thione ( 39 ) was obtained by the action of phosphorus pentasulfide on 38. 4-Amino-3-cyanopyridazine ( 16 ) when treated with formamide produced 8-aminopyrimido[5,4-c]-pyridazine ( 41 ). The synthesis of 4-aminopyridazine-3-carboxamide ( 36 ) and 4-amino-3-cyanopyridazine ( 16 ), both key intermediates in the synthesis of the novel pyrimido[5,4-c]pyridazine ring system was accomplished by the Reissert reaction of 4-aminopyridazine-2-oxides and subsequent conversion of the nitrile to the amide. 相似文献
19.
The 3-aminocarbazoles 1a-e were condensed with phenyl and benzyl isothiocyanates on montmorillonite K10 clay or TLC-grade silica gel at room temperature to furnish efficiently the N-phenyl and N-benzylthioureidocarbazoles, 2a-e and 2f, respectively, within minutes. When adsorbed on montmorillonite K10 clay impregnated with para-toluene sulfonic acid (1:1, w/w) and heated at 60-70 °C, 2a-e and 2f furnished the 2-anilino and 2-benzylaminothiazolo[4,5-c]carbazoles, 3a-e and 3f, respectively, regioselectively in high yields. The cyclisation was also effective for the N-methylthioureidocarbazoles 2g-i. 相似文献
20.
Amol Maruti Jadhav Sandip Gangadhar Balwe Jong Su Kim Kwon Taek Lim Yeon Tae Jeong 《Tetrahedron letters》2019,60(7):560-565
An efficient, inexpensive and environmentally friendly synthesis of novel 3-amino-2-benzoyl-1-aryl-1H-pyrazolo[1,2-b]phthalazine-5,10-dione and 3-amino-2-benzoyl-1-aryl-1H-pyrazolo[1,2-a]pyridazine-5,8-dione derivatives has been developed via one-pot three-component reaction of phthalhydrazide or maleic hydrazide, aldehydes and arylacetonitrile in the presence of catalytic amount of InCl3 as a Lewis acid catalyst under solvent-free conditions. The most important features of the present protocol are mild reaction conditions, short reaction times, high yields, and a wide range of functional group tolerance. 相似文献