- One-step Synthesis of Long-chain Aliphatic α,ω-Dicarboxylic Acids Utilizing the Copper-catalyzed Reaction of β-Propiolactone with α,ω-Di-Grignard Reagents
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Copper-catalyzed reaction of β-propiolactone with α,ω-di-Grignard reagents, followed by esterification gave six-carbon homologated α,ω-dicarboxylic acid esters in good yields.
- Fujisawa, Tamotsu,Sato, Toshio,Kawara, Tatsuo,Tago, Hideyuki
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- Production of Odd-Carbon Dicarboxylic Acids in Escherichia coli Using an Engineered Biotin-Fatty Acid Biosynthetic Pathway
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Dicarboxylic acids are commodity chemicals used in the production of plastics, polyesters, nylons, fragrances, and medications. Bio-based routes to dicarboxylic acids are gaining attention due to environmental concerns about petroleum-based production of these compounds. Some industrial applications require dicarboxylic acids with specific carbon chain lengths, including odd-carbon species. Biosynthetic pathways involving cytochrome P450-catalyzed oxidation of fatty acids in yeast and bacteria have been reported, but these systems produce almost exclusively even-carbon species. Here we report a novel pathway to odd-carbon dicarboxylic acids directly from glucose in Escherichia coli by employing an engineered pathway combining enzymes from biotin and fatty acid synthesis. Optimization of the pathway will lead to industrial strains for the production of valuable odd-carbon diacids.
- Haushalter, Robert W.,Phelan, Ryan M.,Hoh, Kristina M.,Su, Cindy,Wang, George,Baidoo, Edward E. K.,Keasling, Jay D.
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- Aerobic oxidation of cycloalkanes, alcohols and ethylbenzene catalyzed by the novel carbon radical chain promoter NHS (N-hydroxysaccharin)
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Replacement of Ishii's N-hydroxyphthalimide (NHPI) with the novel carbon radical chain promoter N-hydroxysaccharin (NHS) affords, in combination with metal salts, notably Co, or other additives, selective catalytic autoxidation of hydrocarbons, alcohols and alkylbenzenes under mild conditions (25-100°C, O2 1 atm). The effects of solvent, temperature and the nature of the additives were investigated to give an optimised oxidation protocol for the various systems. The NHS/Co combination was more reactive than NHPI/Co in the autoxidation of cycloalkanes. In contrast, the opposite order of reactivity was observed in the autoxidation of ethylbenzene and alcohols. It is suggested, on the basis of bond dissociation energy (BDE) considerations, that this is a result of a change in the rate-limiting step with the more reactive ethylbenzene and alcohol substrates. In the autoxidation of the model cycloalkane, cyclododecane, the best results (90% selectivity to a 4:1 mixture of alcohol and ketone at 24% conversion) were obtained with NHS/Co(acac)3 in PhCF3 at 80°C. Competition experiments revealed that, in contrast to what is commonly believed, formation of the dicarboxylic acid by ring opening is not a result of further oxidation of the ketone product. It is suggested that ring opened products are a result of β-scission of the cycloalkoxy radical formed via (metal-catalysed) decomposition of the hydroperoxide. This is suppressed in the presence of NHS (or NHPI) which efficiently scavenge the alkoxy radicals.
- Baucherel, Xavier,Gonsalvi, Luca,Arends, Isabel W. C. E.,Ellwood, Simon,Sheldon, Roger A.
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p. 286 - 296
(2007/10/03)
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- A new, modulated, oxidative ring cleavage of α-nitrocycloalkanones by Oxone: Synthesis of α,ω-dicarboxylic acids and α,ω-dicarboxylic acid monomethyl esters
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By the appropriate choice of the reaction conditions Oxone produces the ring cleavage of α-nitrocycloalkanones affording good yields of α,ω-dicarboxylic acids and α,ω-dicarboxylic acid monomethyl esters, respectively, regardless the ring size and/or the presence of an alkyl group as substituent.
- Ballini, Roberto,Curini, Massimo,Epifano, Francesco,Marcotullio, Maria Carla,Rosati, Ornelio
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p. 1049 - 1050
(2007/10/03)
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- SYNTHESIS OF PENTADECANEDIOIC ACID FROM CYCLODECANONE OR DODECANEDIOIC ACID
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Methods were developed for the production of pentadecanedioic acid from cyclododecanone or dodecanedioic acid.
- Zakharkin, L. I.,Guseva, V. V.
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p. 281 - 284
(2007/10/02)
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