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A series of imidazolidin‐4‐one derivatives was synthesized via a domino reaction of aldiminoesters and dialkylzinc. Chiral ligands were also examined in this reaction to obtain optically active products. 相似文献
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Takashi Tozawa Dr. Hitoshi Nagao Yoshinobu Yamane Teruaki Mukaiyama Prof. Dr. 《化学:亚洲杂志》2007,2(1):123-134
Chiral quaternary ammonium phenoxides were readily prepared from commercially available cinchona alkaloids and proved to be useful new asymmetric organocatalysts. Among various chiral quaternary ammonium phenoxides, a cinchonidine‐derived catalyst that bears both a sterically hindered N1‐9‐anthracenylmethyl group and a strongly electron withdrawing 9‐O‐3,5‐bis(trifluoromethyl)benzyl group were found to be highly effective for the Michael addition of ketene silyl acetals (derived from phenyl carboxylates) and α,β‐unsaturated ketones followed by lactonization. Optically active 3,4‐dihydropyran‐2‐one derivatives were obtained in high yields with excellent control of enantio‐ and diastereoselectivity. This catalyst can be handled in air and stored at room temperature in a sealed bottle without decomposition for at least one month. 相似文献
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Elena S. Komarova Vadim A. Makarov Vladimir G. Granik Cyril Párkányi 《Journal of heterocyclic chemistry》2012,49(5):969-998
The procedures for the synthesis of substituted pyrazolo[3,4‐b]pyridine‐6‐ones and some of their properties are reviewed. 相似文献
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Xuan Ding Chun‐Lin Dong Zhi Guan Yan‐Hong He 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(1):124-130
The combination of photoredox and enzymatic catalysis for the direct asymmetric one‐pot synthesis of 2,2‐disubstituted indol‐3‐ones from 2‐arylindoles through concurrent oxidization and alkylation reactions is described. 2‐Arylindoles can be photocatalytically oxidized to 2‐arylindol‐3‐one with subsequent enantioselective alkylation with ketones catalyzed by wheat germ lipase (WGL). The chiral quaternary carbon center at C2 of the indoles was directly constructed. This mode of concurrent photobiocatalysis provides a mild and powerful strategy for one‐pot enantioselective synthesis of complex compounds. The experiments proved that other lipases containing structurally analogous catalytic triad in the active site also can catalyze the reaction in the same way. This reaction is the first example of combining the non‐natural catalytic activity of hydrolases with visible‐light catalysis for enantioselective organic synthesis and it does not require any cofactors. 相似文献
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5‐Unsubstituted Pyrido[3,2,1‐jk]carbazol‐6‐ones: Syntheses,Substitution, and Cyclization Reactions
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Wolfgang Stadlbauer Van Hoai Dang Nikolaus Guttenberger 《Journal of heterocyclic chemistry》2015,52(1):114-123
The synthesis of the 5‐unsubstituted pyrido[3,2,1‐jk]carbazol‐6‐one 4 can be achieved by the reaction of carbazole ( 1 ) and malonate derivatives, either in a three‐step synthesis via 5‐acetyl‐pyridocarbazolone 3 or in a one‐step reaction from 1 and malonic acid/phosphoryl chloride. The 5‐acetyl derivative 5 can be transformed via a tosylate intermediate to 4‐azido‐pyridocarbazolone 11 , which cyclizes by thermal decomposition to the isoxazolo‐pyrido[3,2,1‐jk]carbazolone 12 . The thermolysis conditions were investigated by DSC. Nitration of pyridocarbazolone 4 and subsequent introduction of azide leads to azido derivative 23 , which cyclizes on thermolysis to furazan‐oxide derivative 24 . Again, the thermolysis conditions were investigated by DSC. 5‐Chloro‐5‐nitro‐pyrido[3,2,1‐jk]carbazole‐4,6‐dione, obtained from 4 by subsequent nitration and chlorination, forms by exchange of both 5‐substituents 5,5‐dihydroxy‐pyridocarbazoledione 17 , which acylates phenol to give 5‐hydroxy‐5‐(p‐hydroxyphenyl)‐pyridocarbazoledione 20 . Acid‐catalyzed cyclodehydration of 20 forms a highly fused benzofuro‐pyridocarbazole 21 . Another C–C coupling at position 5 starts from 4‐chloro‐5‐nitro‐pyridocarbazolone 22 and diethyl malonate 2a , which forms the diethyl (nitrocarbazolyl)malonate 25 . With dimethyl malonate 2c , the intermediate dimethyl (nitrocarbazolyl)malonate gives on thermolysis the (nitrocarbazolyl)acetate 27 by loss of one ester group. 相似文献
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Synthesis of Novel Heterocycles Derived from 4‐Arylmethylene‐2‐phenyl‐1,3‐oxazole‐5(4H)‐ones
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Ahmed S. A. Youssef Kamal A. Kandeel Wael S. I. Abou‐Elmagd David S. A. Haneen 《Journal of heterocyclic chemistry》2016,53(3):809-816
The acid hydrazide derivatives 2 were converted into pyrazolone, triazinone, and schiff bases. However, the reaction of Schiff base 12 with malononitrile or thioglycolic acid gives the pyrazolotriazinone or thiazolidinone derivative, respectively. The structures of the newly synthesized compounds were established on the basis of IR, 1H‐NMR, mass spectral data, and elemental analyses. The antimicrobial activities of the synthesized compounds were examined against two types of bacteria and two types of fungi. Some of the tested compounds showed promising activities. 相似文献
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Saleh M. Al‐Mousawi Morsy A. El‐Apasery Najat Al‐Kandery Mohamed H. Elnagdi 《Journal of heterocyclic chemistry》2008,45(2):359-364
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A highly enantioselective catalytic double‐Michael addition reaction of substituted benzofuran‐2‐ones with divinyl ketones promoted by readily accessible tertiary amine–thiourea Cinchona alkaloids has been developed. A number of optically enriched spirocyclic benzofuran‐2‐ones were prepared in very good yields (up to 99 %), diastereoselectivities (up to 19:1 d.r.), and very good enantioselectivities (up to 92 % ee). Density functional theory (DFT) calculations were performed to investigate the origin of stereoselectivity. 相似文献
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Furo[3,2‐c]pyran‐4‐ones, which possess a natural‐product skeleton, are synthesized via a simple, one‐pot, three‐component reaction of furan‐2,3‐diones with dialkyl acetylenedicarboxylates and Ph3P. 相似文献
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Adriana M. das Neves Jos C. Campos Daniela P. Gouvêa Gabriele A. Berwaldt Taís B. Goulart Cinara T. Avila Pablo Machado Gergia C. Zimmer Wilson Cunico 《Journal of heterocyclic chemistry》2019,56(1):251-259
This work reports the synthesis of thiazolidin‐4‐ones and thiazinan‐4‐ones analogous to rosiglitazone, a potent antidiabetic drug. The desired compounds were synthesized with moderate to good yields by one‐pot reactions between different primary amines, mercaptoacetic or mercaptopropionic acids, and the 4‐(2‐(methyl(pyridin‐2‐yl)amino)ethoxy)benzaldehyde. The cyclocondensation reactions were carried out for 20 h, and all the products were characterized by 1H and 13C nuclear magnetic resonance spectroscopy, mass spectrometry, and one example by X‐ray diffraction. 相似文献
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Hyun‐A Chung Young‐Jin Kang D. H. Kweon Woo Song Lee Yong‐Jin Yoon 《Journal of heterocyclic chemistry》2000,37(6):1443-1446
This paper presents the synthesis of 1‐[(pyrazol‐3‐yl)methyl]pyridazin‐6‐ones from ethyl 4‐(4,5‐dichloro‐6‐oxopyridazin‐1‐yl)‐3‐oxobutanoate. 相似文献
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PauloJ. Coelho LuisM. Carvalho JosC. Silva AnaM.F. Oliveira‐Campos Andr Samat Robert Guglielmetti 《Helvetica chimica acta》2001,84(1):117-123
The synthesis of four novel pyrano‐xanthenones derived from hydroxy‐9H‐xanthen‐9‐ones is described, and their photochromic properties in solution are reported. All compounds synthesized exhibit a good colorability, making them good potential dyes. The presence of the chromone system fused in the 7,8‐position seems to lead to more stabilized colored forms. 相似文献