- Carbon dioxide utilization via carbonate-promoted C-H carboxylation
-
Using carbon dioxide (CO2) as a feedstock for commodity synthesis is an attractive means of reducing greenhouse gas emissions and a possible stepping-stone towards renewable synthetic fuels. A major impediment to synthesizing compounds from CO2 is the difficulty of forming carbon-carbon (C-C) bonds efficiently: although CO2 reacts readily with carbon-centred nucleophiles, generating these intermediates requires high-energy reagents (such as highly reducing metals or strong organic bases), carbon-heteroatom bonds or relatively acidic carbon-hydrogen (C-H) bonds. These requirements negate the environmental benefit of using CO2 as a substrate and limit the chemistry to low-volume targets. Here we show that intermediate-temperature (200 to 350 degrees Celsius) molten salts containing caesium or potassium cations enable carbonate ions (CO32-) to deprotonate very weakly acidic C-H bonds (pKa > 40), generating carbon-centred nucleophiles that react with CO2 to form carboxylates. To illustrate a potential application, we use C-H carboxylation followed by protonation to convert 2-furoic acid into furan-2,5-dicarboxylic acid (FDCA) - a highly desirable bio-based feedstock with numerous applications, including the synthesis of polyethylene furandicarboxylate (PEF), which is a potential large-scale substitute for petroleum-derived polyethylene terephthalate (PET). Since 2-furoic acid can readily be made from lignocellulose, CO32--promoted C-H carboxylation thus reveals a way to transform inedible biomass and CO2 into a valuable feedstock chemical. Our results provide a new strategy for using CO2 in the synthesis of multi-carbon compounds.
- Banerjee, Aanindeeta,Dick, Graham R.,Yoshino, Tatsuhiko,Kanan, Matthew W.
-
p. 215 - 219
(2016/03/22)
-
- TUBULIN BINDING AGENTS
-
The invention provides combretastatin A-4 like compounds that are modified to have enhanced tubulin binding activity and in some embodiments the ability to promote accumulation in the vasculature undergoing angiogenesis (homing activity). The compounds are based on the combretastatin A-4 skeletal structure having a tubulin-binding pharmacophore comprising two fused rings (A and B rings) in which the B ring is substituted with (a) an aromatic ring structure (C ring) and (b) a second substituent/functional group that comes off the B ring. The aromatic ring structure is typically a six membered ring phenolic or aniline structure, or may also be a fused ring structure such as a substituted or unsubstituted naphthalene. The second substituent on the B ring may for example be a substituent which has been found to provide enhanced tubulin binding activity (for example a carbonyl group), or may be a substituent that facilitates functionalisation of the B ring (for example an hydroxyl or amine group), or it may be a binding agent for a target that is preferentially expressed on vasculature undergoing angiogenesis, and not expressed on quiescent vasculature.
- -
-
Paragraph 0897; 0898; 0899; 0900; 0901; 0902; 0903
(2015/02/18)
-
- Azetidines
-
The invention relates to EP2 antagonist azetidines of formula (I) wherein Ar, R1, X, and Z are as defined herein, to their use in medicine, particularly in the treatment of endometriosis and/or uterine fibroids, to intermediates useful in their synthesis, and to compositions containing them.
- -
-
Page/Page column 33
(2008/12/08)
-
- An improved method for product separation in metathetical reactions and its demonstration for the synthesis of anhydrous cesium salts
-
In conventional metathetical reactions, product separation is based on solubility product differences, and the resulting products are often impure and require purification by recrystallization. A new approach to product separation is described that relies on the formation of an unstable, volatile by-product, such as NH4+CH3O-. This method provides very pure and anhydrous products in high yield and was demonstrated successfully for the syntheses of anhydrous cesium salts.
- Haiges, Ralf,Christe, Karl O.
-
p. 1717 - 1718
(2008/10/08)
-
- Nucleophilic addition to acetylenes in superbasic catalytic systems: XI. Transformations of alkali metal hydroxides during vinylation of 1-heptanol with acetylene under elevated pressure
-
Base-catalyzed addition of 1-heptanol to acetylene under elevated pressure of the latter is accompanied by side processes including formation of carboxylic acid salts (alkali metal heptanoates and acetates) with liberation of hydrogen and acetylene polyme
- Oparina,Parshina,Khil'ko,Gorelova,Preiss,Henkelmann,Trofimov
-
p. 1553 - 1558
(2007/10/03)
-
- Process of preparing cesium salts from cesium aluminum alum
-
This invention relates to the preparation of cesium salts from cesium-aluminum-alum in a process in which the cesium-aluminum-alum is reacted in a single vessel in the presence of water with calcium hydroxide in an amount which is equimolar to the amount of aluminum and with a readily water-soluble calcium salt in an amount which is equimolar to the amount of cesium and the precipitated aluminum hydroxide and the precipitated calcium sulfate are separated by filtration or centrifugation.
- -
-
-
- ANTI-HIV (AIDS) AGENTS
-
Compounds of formula STR1 wherein Ar, W, Z, Q, R 1, U, and T are as set forth herein, are described. These compounds are active as agents against retroviruses and in particular against HIV.
- -
-
-
- A PROCEDURE FOR ALCOHOL INVERSION USING CESIUM ACETATE
-
A convenient and efficient procedure for alcohol inversion by means of the reaction of mesylates or alkyl halides with cesium acetate is described.
- Huffman, John W.,Desai, Ranjit C.
-
p. 553 - 558
(2007/10/02)
-
