- Synthesis of Esters by Functionalisation of CO2
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The invention relates to a method for (I) producing a carboxylic ester of formula (I). Said method comprises the steps of: a) bringing an organosilane/borane of formula Si or B into contact with CO2, in the presence of a catalyst and an electrophilic compound of formula (III), the groups R1, R2, R3, R4, R5, Y, and M′ being as defined in claim 1; and optionally b) recovering the compound of formula (I) produced.
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Paragraph 0129
(2017/09/06)
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- CO2 Conversion into Esters by Fluoride-Mediated Carboxylation of Organosilanes and Halide Derivatives
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A one-step conversion of CO2 into heteroaromatic esters is presented under metal-free conditions. Using fluoride anions as promoters for the C-Si bond activation, pyridyl, furanyl, and thienyl organosilanes are successfully carboxylated with CO2 in the presence of an electrophile. The mechanism of this unprecedented reaction has been elucidated based on experimental and computational results, which show a unique catalytic influence of CO2 in the C-Si bond activation of pyridylsilanes. The methodology is applied to 18 different esters, and it has enabled the incorporation of CO2 into a polyester material for the first time. Metal free! A novel methodology is described to convert CO2 into heteroaromatic esters in the presence of organosilanes and organic halides using fluoride anions as promoters for the C-Si bond activation (see scheme). CO2 exhibits a unique catalytic influence in the C-Si bond cleavage of pyridylsilanes, serving as a traceless activator.
- Frogneux, Xavier,Von Wolff, Niklas,Thuéry, Pierre,Lefèvre, Guillaume,Cantat, Thibault
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p. 2930 - 2934
(2016/03/25)
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- Development of an iron(II)-catalyzed aerobic catechol cleavage and biomimetic synthesis of betanidin
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An aerobic iron(II)-catalyzed cleavage of catechols was developed. This reaction allows for the preparation of 2-methoxy-2H-pyrans that can be employed as versatile building blocks for synthesis. The utility of this biomimetic oxidative cleavage is featured in the synthesis of betanidin, a natural colorant with antioxidant properties. Cut and paste: An aerobic iron(II)-catalyzed oxidative cleavage of catechol was developed. This reaction allows the preparation of 2H-pyrans that can be employed as versatile building blocks for synthesis. The utility of this biomimetic cleavage is featured in the synthesis of betanidin, the aglycone of red beets' principal colorant and itself a valuable antioxidant (see scheme).
- Guimond, Nicolas,Mayer, Peter,Trauner, Dirk
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supporting information
p. 9519 - 9523
(2014/08/18)
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- Fe(PyTACN)-catalyzed cis-dihydroxylation of olefins with hydrogen peroxide
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A family of iron complexes with general formula [Fe(II)( R,Y,XPyTACN)(CF3SO3)2], where R,Y,XPyTACN=1-[2′-(4-Y-6-X-pyridyl)methyl]-4,7-dialkyl-1,4, 7-triazacyclononane, X and Y refer to the groups at positions 4 and 6 of the pyridine, respectively, and R refers to the alkyl substitution at N-4 and N-7 of the triazacyclononane ring, are shown to be catalysts for efficient and selective alkene oxidation (epoxidation and cis-dihydroxylation) employing hydrogen peroxide as oxidant. Complex [Fe(II)(Me,Me,HPyTACN)(CF 3SO3)2] (7), was identified as the most efficient and selective cis-dihydroxylation catalyst among the family. The high activity of 7 allows the oxidation of alkenes to proceed rapidly (30 min) at room temperature and under conditions where the olefin is not used in large amounts but instead is the limiting reagent. In the presence of 3 mol% of 7, 2 equiv. of H2O2 as oxidant and 15 equiv. of water, in acetonitrile solution, alkenes are cis-dihydroxylated reaching yields that might be interesting for synthetic purposes. Competition experiments show that 7 exhibits preferential selectivity towards the oxidation of cis olefins over the trans analogues, and also affords better yields and high [syn-diol]/[epoxide] ratios when cis olefins are oxidized. For aliphatic substrates, reaction yields attained with the present system compare favourably with state of the art Fe-catalyzed cis-dihydroxylation systems, and it can be regarded as an attractive complement to the iron and manganese systems described recently and which show optimum activity against electron-deficient and aromatic olefins. Copyright
- Prat, Irene,Font, David,Company, Anna,Junge, Kathrin,Ribas, Xavi,Beller, Matthias,Costas, Miquel
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supporting information
p. 947 - 956
(2013/05/08)
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- 1-(Aromatic- or heteroaromatic-substituted)-3-(heteroaromatic substituted)-1,3-propanediones and uses thereof
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Certain 1-(aromatic- or heteroaromatic-substituted-3-(heteroaromatic substituted)-1,3-propanediones are described as inhibitors of HIV integrase and inhibitors of HIV replication. These compounds are useful in the prevention or treatment of infection by HIV and the treatment of AIDS, either as compounds, pharmaceutically acceptable salts, pharmaceutical composition ingredients, whether or not in combination with other antivirals, immunomodulators, antibiotics or vaccines. Methods of treating AIDS and methods of preventing or treating infection by HIV are also described.
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- Heterocyclic substituted aniline calcium channel blockers
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The present invention provides compounds that block calcium channels having the Formula I shown below. STR1The present invention also provides methods of using the compounds of Formula I to treat stroke, cerebral ischemia, head trauma, epilepsy, asthma, amyotrophic lateral sclerosis, or pain and to pharmaceutical compositions that contain the compounds of Formula I.
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- Multiple Paths for Photo-methylation and -methoxylation of Methyl 2-Pyridinecarboxylate in Methanol
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UV-irradiation of methyl 2-pyridinecarboxylate in methanol in the absence of added acid brings about methylation at the 5-position via the excitation of C=O of the ester group, while in the presence of added acid the 4-position of the pyridine ring is methylated.In the presence of sulfuric acid methoxylation via an excimer is dominant over methylation.In the presence of hydrochloric acid methylation via chlorine atoms becomes dominant.
- Sugiyama, Toru,Furihata, Toshikazu,Takagi, Kyoko,Sato, Michitsugu,Akiyama, Shinya,et al.
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p. 3785 - 3789
(2007/10/02)
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- MULTIPLE PATHS FOR PHOTOALKYLATION OF PYRIDINECARBOXYLIC ESTERS IN ALCOHOLS
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Photochemical substitution of ring hydrogen of pyridinecarboxylic esters by alkyl groups derived from solvent alcohols occurs in several paths: 1) alkylation initiated by excited carbonyl moiety of the ester group and 2) alkylation initiated by the excitation of the ?-electronic system of the pyridine ring.In the photoreaction of methyl 3-pyridinecarboxylate in acidic methanol, three types of excited state (two triplet states for alkylation and a singlet state for alkoxylation) contribute simultaneously.
- Sugiyama, Toru,Tobita, Estuo,Takagi, Kyoko,Sato, Michitsugu,Kumagai, Yasuyuki,et al.
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p. 131 - 134
(2007/10/02)
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