- Synthesis and tautomerism of curcumin derivatives and related compounds
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1,7-Bis(4′-hydroxy-3′-trifluoromethoxyphenyl)-1,6-heptadiene-3,5-dione (2a), related to curcumin, and thirteen 4-substituted derivatives were prepared and their keto/enol ratio in DMSO[D6] was determined by 19F NMR because the enolic form of these related curcumins had been shown to bind to amyloid plaques in the Alzheimer brain. The parent compound and the 4-ethoxycarbonyl derivative were almost 100% in the enolic form that contains a conjugated hepta-1,4,6-trien-3-on-5-ol backbone. Enolisation decreased to varying amounts in the derivatives that had 4-substituted alkyl groups. Attempts to prepare the 4-hydroxypropyl derivative by hydrolysis of O-methoxymethyl 2m or O-tetrahydropyranyloxy 2n protected derivatives led to cyclised products. A related pyrimidine compound 6b that mimicked a fixed enol form was also prepared.
- Taguchi, Hiroyasu,Yanagisawa, Daijiro,Morikawa, Shigehiro,Hirao, Koichi,Shirai, Nobuaki,Tooyama, Ikuo
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- ONE-STEP, FAST, 18F-19F ISOTOPIC EXCHANGE RADIOLABELING OF DIFLUORO-DIOXABORININS AND USE OF SUCH COMPOUNDS IN TREATMENT
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A compound according to Formula (I) or a pharmaceutically acceptable salt and/or solvate thereof, wherein X1 and X2 are each independently 18F or 19F; R1 and R2 are each independently alkyl, amine, perfluoroalkyl, alkenyl, alkynyl, aryl, or aralkenyl; and R3 is H, halo, alkyl, alkyl ester, alkenyl, alkynyl, aryl, or aralkenyl; or wherein: R1 and R3 or R2 and R3 join to form a 6-membered cycloalkyl or heterocyclyl; or R1 and R3, R2 and R3, or R1, R2, and R3 join to form a substituted or unsubstituted polycyclic ring, wherein the polycyclic ring comprises fused cycloalkyl, heterocycloalkyl, aryl, or heteroaryl rings.
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Paragraph 0019; 0202-0203
(2019/12/15)
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- Chemiluminescence in decomposition of bridged 1,2,4,5-tetraoxanes catalyzed by ferrocene
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Chemiluminescence was observed in ferrocene-catalyzed decomposition of bridged 1,2,4,5-tetraoxanes, namely, 2,3,5,6-tetraoxabicyclo[2.2.1]heptanes. The chemi- and photoluminescence spectra revealed the main products and luminescence emitters to be β-diket
- Galimov, Dim I.,Gazeeva, Dilara R.,Bulgakov, Ramil G.,Terent'ev, Alexander O.
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p. 371 - 373
(2017/08/02)
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- Direct imine acylation for molecular diversity in heterocyclic synthesis
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Imines and carboxylic acids have been directly coupled using propylphosphonic acid anhydride and NEt(i-Pr)2 to give N-acyliminium ions, which were intramolecularly trapped with oxygen, nitrogen, sulfur, and carbon nucleophiles to provide a wide range of structurally diverse heterocycles.
- Unsworth, William P.,Coulthard, Graeme,Kitsiou, Christiana,Taylor, Richard J. K.
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p. 1368 - 1376
(2014/03/21)
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- ALKYLATION OF CH ACIDS IN THE PRESENCE OF POTASSIUM CARBONATE. IV. ALKYLATION OF 2,4-PENTANEDIONE AND 3-METHYL-2,4-PENTANEDIONE
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The reaction of 2,4-pentanedione and 3-methyl-2,4-pentanedione with ethyl acrylate in the presence of potassium carbonate gave the Michael adducts.The acylotropic rearrangement of the products from the reaction of 3-methyl-2,4-pentanedione with ethyl α-bromoacrylate and dibromoethane under the influence of potassium carbonate was investigated.
- Khachatryan, D. S.,Vardapetyan, A. A.,Panosyan, G. A.,Mirzoyan, R. G.,Morlyan, N. M.
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p. 1806 - 1810
(2007/10/02)
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- An efficient route to dipyrrinones: Synthesis of xanthobilirubic acid methyl ester
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Structurally interesting and complicated dipyrrinones, such as xanthobilirubic acid methyl ester (9), can be synthesized on a large scale from simple, inexpensive starting materials like ethyl acetoacetate, 2,4-pentanedione (1) and ethyl acrylate in 8 steps with an average yield of 80% at each step and an overall 17% yield.
- Shrout,Lightner
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p. 1062 - 1065
(2007/10/02)
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- Xanthobilirubic Acid and Its Amides. Synthesis, Spectroscopy, and Solution Structures
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Xanthobilirubic acid, 5--2,4-dimethyl-1H-pyrrol-3-propanoic acid, its methyl ester, amide, N-methylamide and dimethylamide, and kryptopyrromethenone have been synthesized and characterized spectroscopically.In d6-DMSO solution all pyrromethenones were monomeric, with lactam and pyrrole N-Hs H-bonded to solvent.In deuteriochloroform, the pyrromethenones preferred a dimeric form, with intramolecular H-bonding between the lactam C=O of one unit and the lactam and pyrrole N-Hs of the second.
- Lightner, D. A.,Ma, J.-S.,Adams, T. C.,Franklin, R. W.,Landen, G. L.
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p. 139 - 144
(2007/10/02)
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- Nickel-Catalyzed Michael Additions of β-Dicarbonyls
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Bis(2,4-pentanedionato)nickel(II) is found to be a mild, efficient, and simple to use catalyst for the Michael additions of β-dicarbonyls.Yields are higher than with traditional strongly basic catalysts, unwanted side reactions are reduced, and workup procedures are greatly simplified.The reactions appear to be quite general as β-diketones, β-keto esters, β-keto amides, and β-diesters are all found to react.A rational mechanism which suggests further research is presented.
- Nelson, John H.,Howells, Peter N.,DeLullo, George C.,Landen, George L.,Henry, Ronald A.
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p. 1246 - 1249
(2007/10/02)
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