- Synthesis of 1,3,5-tricarbonyl derivatives by condensation of 1,3-bis(silyl enol ethers) with acid chlorides
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A variety of 1,3,5-tricarbonyl derivatives were prepared by reaction of 1,3-bis(silyl enol ethers) with acid chlorides under mild conditions. This includes reactions of both aromatic and aliphatic acid chlorides and bis(acid chlorides). The yields vary de
- Rahn, Thomas,Nguyen, Van T. H.,Dang, T. H. Tam,Ahmed, Zafar,Methling, Karen,Lalk, Michael,Fischer, Christine,Spannenberg, Anke,Langer, Peter
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p. 1957 - 1961
(2007/10/03)
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- SmCl3-catalyzed C-acylation of 1,3-dicarbonyl compounds and malononitrile
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(Chemical Equation Presented) A recyclable, convenient, and efficient catalytic system for C-acylation of 1,3-dicarbonyl compounds and malononitrile with acid chlorides has been developed, giving moderate to excellent yields under mild conditions. This is the first catalytic example of such reactions. In addition, by applying this protocol as the key step, 3,5-disubstituted-1H- pyrazole-4-carboxylate can easily be synthesized in high yields in a one-pot procedure.
- Shen, Quansheng,Huang, Wen,Wang, Jialiang,Zhou, Xigeng
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p. 4491 - 4494
(2008/03/12)
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- Catalytic action of azolium salts. VIII. Oxidative aroylation with arenecarbaldehydes catalyzed by 1,3-dimethylbenzimidazolium iodide
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Refluxing of a mixture of benzaldehyde (1a), 1,3- dimethylbenzimidazolium iodide (7), p-nitroaniline (9b) as an oxidizing agent, and 1,8-diazabicyclo[5,4,0]-7-undecene (DBU) in MeOH afforded methyl benzoate (2a) in good yield. Other methyl arenecarboxylates 2 were similarly obtained from arenecarbaldehydes 1. We showed that this aroylation proceeds via the 2-aroyl-1,3-dimethylbenzimidazolium salt (8). The 1,2,4-triazolium salt (18) and the naphtho[1,2-d]imidazolium salt (19) were also effective catalysts for this oxidative aroylation. However, the aroylation did not proceed with the imidazolium salt (20). In the presence of flavins (25a - c), arenecarbaldehydes 1 reacted in MeOH under aerobic conditions catalyzed by the benzimidozolium salt 7 to give the corresponding methyl arenecarboxylates 2. 1-Methyl-3-[3-(10-phenylisoalloxazin-3-yl)propyl]benzimidazolium bromide (27) is an effective complex catalyst for this oxidative aroylation.
- Miyashita, Akira,Suzuki, Yumiko,Nagasaki, Izuru,Ishiguro, Chie,Iwamoto, Ken-Ichi,Higashino, Takeo
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p. 1254 - 1258
(2007/10/03)
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- Photo-isomerisations reversibles d'enols dans la serie des triacylmethanes
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Interconversions between chelated enolic configurational isomers E and Z take place when equilibrated solutions of enolised triacylmethanes ArCO(RCO)CHCOR' are irradiated.It is concluded that isomerization takes place directly by rotation around the olefinic double bond of the enolic ring after cleavage of the intramolecular hydrogen bond.
- Couchouron, Benoit,Saint, Jacques Le,Courtot, Pierre
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p. 381 - 384
(2007/10/02)
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