- Ambient carboxylation on a supported reversible CO2 carrier: Ketone to β-keto ester
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A reversible CO2 carrier (RCC) has been developed to perform carboxylation of ketone to β-ketoester under ambient CO2 pressure and temperature. RCC has been synthesized by immobilizing 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) on methylhydrosiloxane support and reacting with CO2 with 100% degree of functionalisation. RCC is found to be recyclable and shows retention of activity in 5 recycles. CO2 absorption under ambient temperature and desorption at 120°C renders the material suitable for carrying out carboxylation reactions at 25°C with excellent yields. The yield of the reaction can reach up to 100% with TON 200 in 4 h. The extent of the reaction primarily depends upon enol content of the substrate. β-Ketoacid produced during the reaction can be isolated and converted to its corresponding methyl ester derivative by reacting with methyl iodide.
- Beckman, Eric J.,Munshi, Pradip
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Read Online
- Synthesis of New Tricyclic and Tetracyclic Fused Coumarin Sulfonate Derivatives and Their Inhibitory Effects on LPS-Induced Nitric Oxide and PGE2 Productions in RAW 264.7 Macrophages: Part 2
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The synthesis of a new series of 21 fused coumarin derivatives is described, and the biological evaluation of their in vitro antiinflammatory effects as inhibitors of lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production in RAW 264.7 macrophages. The target compounds 1a–u were first tested for cytotoxicity to determine a non-toxic concentration for antiinflammatory screening, so that the inhibitory effects against NO and PGE2 production would not be caused by cytotoxicity. Compounds 1f and 1p were the most active PGE2 inhibitors with IC50 values of 0.89 and 0.95 μM, respectively. Western blot and cell-free COX-2 screening showed that their effects were due to inhibition of both COX-2 protein expression and COX-2 enzyme activity. Their IC50 values against the COX-2 enzyme were 0.67 and 0.85 μM, respectively, which is more potent than etoricoxib. The selectivity indexes of compounds 1f and 1p against COX-2 compared to COX-1 were 41.1 and 42.5, respectively. Compound 1f showed strong inhibitory effects at 5 μM concentration on COX-2 mRNA expression in LPS-induced RAW 264.7 macrophages. Moreover, the tricyclic compounds 1l and 1n as well as the tetracyclic analog 1u were the most potent NO inhibitors, with one-digit micromolar IC50 values. They showed dose-dependent inhibition of inducible nitric oxide synthase (iNOS) protein expression. The tetracyclic derivative 1u was the most potent inhibitor of NO production. It also exhibited a strong inhibitory effect on iNOS mRNA expression in LPS-induced RAW 264.7 macrophages.
- El-Gamal, Mohammed I.,Lee, Woo-Seok,Shin, Ji-Sun,Oh, Chang-Hyun,Lee, Kyung-Tae,Choi, Jungseung,Myoung, Nohsun,Baek, Daejin
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p. 853 - 863
(2016/11/09)
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- Metal-triflate-catalyzed synthesis of polycyclic tertiary alcohols by cyclization of γ-allenic ketones
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It has been established that bismuth(III) triflate catalyzes the cyclization of γ-allenic ketones under mild reaction conditions. This reaction allows the selective formation of polycyclic tertiary alcohols from cyclic ketone derivatives. The resulting dienols can engage in stereoselective cycloadditions to efficiently afford complex polycyclic systems. Simply complex: The described catalytic carbonyl-ene reaction is efficiently performed under mild reaction conditions by using only 1 mol % of bismuth(III) triflate, thus affording functionalized molecular scaffolds. Complex polycyclic structures with a defined stereochemistry have been synthesized by using the carbonyl-ene products in a subsequent hydroxy-directed Diels-Alder reaction.
- Diaf, Ilhem,Lemiere, Gilles,Dunach, Elisabet
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supporting information
p. 4177 - 4180
(2014/05/06)
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- The aldol type reaction catalyzed by arylmalonate decarboxylase - A decarboxylase can catalyze an entirely different reaction, aldol reaction
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The catalytic promiscuity of AMDase was demonstrated using a well-designed substrate based on the consideration of the reaction mechanism. As the reaction catalyzed by AMDase is supposed to proceed via an enolate intermediate, we expected that the enzyme
- Terao, Yosuke,Miyamoto, Kenji,Ohta, Hiromichi
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p. 420 - 421
(2007/10/03)
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- 2-aminoindane analogs
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The present invention relates to therapeutically active 2-aminoindane analogs of formula (I): Also provided is a method of preparing compounds of formula (I), and pharmaceutical compositions comprising the compounds. The novel compounds act as modulators of metabotropic glutamate receptors and, as such, are useful in treating diseases of the central nervous system related to the metabotropic glutamate receptor system.
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Page/Page column 25
(2010/10/20)
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