Abstract Intramolecular dehydration of erythritol to 1,4-anhydroerythritol proceeded in liquid water at 573 K. The initial formation rate and final yield of 1,4-anhydroerythritol were 0.50 mmol h−1 and 71%, respectively. Addition of carbon dioxide up to the pressure of 17.7 and 24.8 MPa to water solvent at 573 K, the initial product formation rates dramatically increased to 1.45 and 2.10 mmol h−1, respectively; however, the final yields were almost the same as 73 and 71%, respectively. These results showed that the protons derived from carbonic acid catalyzed the intramolecular dehydration and the concentration of proton increased with an increase in the carbon dioxide pressure introduced.
#1Aritomo Yamaguchi(AIST: National Institute of Advanced Industrial Science and Technology)H-Index: 26
#2Natsumi Muramatsu(AIST: National Institute of Advanced Industrial Science and Technology)H-Index: 2
Last. Osamu Sato(AIST: National Institute of Advanced Industrial Science and Technology)H-Index: 28
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The intramolecular dehydration of biomass-derived sugar alcohols D-sorbitol, D-mannitol, galactitol, xylitol, ribitol, L-arabitol, erythritol, L-threitol, and DL-threitol was investigated in high-temperature water at 523–573 K without the addition of any acid catalysts. D-Sorbitol and D-mannitol were dehydrated into isosorbide and isomannide, respectively, as dianhydrohexitol products. Galactitol was dehydrated into anhydrogalactitols; however, the anhydrogalactitols could not be dehydrated into...
Bioassay-guided fractionation of the ethanolic extract of the stems of Aristolochia fordiana led to the isolation of six new dihydrobenzofuran neolignans (1–3 and 7–9), three new 2-aryldihydrobenzofurans (4–6), a new 8-O-4′ neolignan (10), and 14 known analogues (11–24). The structures of compounds 1–10 were established by spectroscopic methods, and their absolute configurations were determined by analyses of the specific rotation and electronic circular dichroism data. The neuroprotective effec...
Poly(butylene terephthalate) (PBT) was decomposed into terephthalic acid (TPA) and tetrahydrofuran (THF) in high-temperature liquid water above 498 K. THF was obtained by the dehydration of the mon...
The hydroxyl group of enantioenriched benzyl, propargyl, allyl, and alkyl alcohols has been intramolecularly displaced by uncharged O-, N-, and S-centered nucleophiles to yield enantioenriched tetrahydrofuran, pyrrolidine, and tetrahydrothiophene derivatives with phosphinic acid catalysis. The five-membered heterocyclic products are generated in good to excellent yields, with high degree of chirality transfer, and water as the only side-product. Racemization experiments show that phosphinic acid...
Heterogeneous ReOx–Pd/CeO2 catalyst showed excellent performance for simultaneous hydrodeoxygenation of vicinal OH groups. High yield (>99 %), turnover frequency (300 h−1), and turnover number (10 000) are achieved in the reaction of 1,4-anhydroerythritol to tetrahydrofuran. This catalyst can be applied to sugar alcohols, and mono-alcohols and diols are obtained in high yields (≥85 %) from substrates with even and odd numbers of OH groups, respectively. The high catalytic performance of ReOx–Pd/...
Last. Joseph Moran(UDS: University of Strasbourg)H-Index: 28
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The inability to decouple Lewis acid catalysis from undesirable Bronsted acid catalysed side reactions when water or other protic functional groups are necessarily present has forced chemists to choose between powerful but harsh catalysts or poor but mild ones, a dichotomy that restricts the substrate scope of dehydrative transformations such as the direct SN1 reaction of alcohols. A systematic survey of Lewis and Bronsted acids reveals that the strong non-hydrolyzable Lewis acid B(C6F5)3 leads ...
#1Aritomo Yamaguchi(AIST: National Institute of Advanced Industrial Science and Technology)H-Index: 26
#2Norihito Hiyoshi(AIST: National Institute of Advanced Industrial Science and Technology)H-Index: 26
Last. Masayuki Shirai(AIST: National Institute of Advanced Industrial Science and Technology)H-Index: 29
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Sorbitol dehydration in high temperature liquid water proceeded at 523–573 K without adding any acid catalysts. Anhydrosorbitols (1,4-anhydrosorbitol (1,4-AHSO), 2,5-anhydrosorbitol (2,5-AHSO) and 1,5-anhydrosorbitol (1,5-AHSO)) were produced by the monomolecular dehydration of sorbitol, and isosorbide was produced by the stepwise dehydration of 1,4-AHSO. The formation rates of 1,4-AHSO and 2,5-AHSO (five-membered cyclic ethers) from sorbitol dehydration were much larger than that of 1,5-AHSO (s...
#1Xiaolu Jiang(Warw.: University of Warwick)H-Index: 1
#2Emma K. London(Warw.: University of Warwick)H-Index: 1
Last. Martin Wills(Warw.: University of Warwick)H-Index: 56
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Gold(I) and (III) salts have been found to be highly effective at the catalysis of ether formation from alcohols. Intramolecular ether formation of a 1,5-diol was also achieved, with a stereoselectivity that indicates that an SN1 mechanism predominates. In an attempt to form a seven-membered ring, a stable 14-membered dimer product was also formed. Attempts to control the diastereoselectivity of the reaction using a chiral anionic counterion did not give products with a high de.
#1Aritomo Yamaguchi(AIST: National Institute of Advanced Industrial Science and Technology)H-Index: 26
#2Norihito Hiyoshi(AIST: National Institute of Advanced Industrial Science and Technology)H-Index: 26
Last. Masayuki Shirai(AIST: National Institute of Advanced Industrial Science and Technology)H-Index: 29
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High-temperature liquid water treatment of triol compounds [1,2,3-propanetriol (glycerol), 1,2,4-butanetriol (1,2,4-BTO), and 1,2,5-pentanetriol (1,2,5-PTO)] was carried out using a batch reactor. Intramolecular dehydration to hydroxyacetone from glycerol, 3-hydroxytetrahydrofuran from 1,2,4-BTO, and both tetrahydrofurfuryl alcohol and 3-hydroxytetrahydropyran from 1,2,5-PTO proceeded in water at 573 K. The dehydration rates were enhanced by the addition of high-pressure carbon dioxide.
Hydrodeoxygenation of erythritol, xylitol, and sorbitol was investigated over Pt-WOx/SiO2 (4 wt% Pt, W/Pt = 0.25, molar ratio) catalyst. 1,4-Butanediol can be selectively produced with 51% yield (carbon based) by erythritol hydrodeoxygenation at 413 K, based on the selectivity over this catalyst toward the regioselective removal of C-O bond in the -O-C-CH2OH structure. Because the catalyst is also active in hydrodeoxygenation of other polyols to some extent but much less active in that of mono-a...
Last. Masayuki Shirai(AIST: National Institute of Advanced Industrial Science and Technology)H-Index: 29
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Alcoholysis of benzyl phenyl ether to various aromatic compounds was studied in high-temperature aqueous methanol solution under high-pressure carbon dioxide conditions. The products formed included benzyl methyl ether, benzyl alcohol, phenol and toluene. As high as 70.7 ± 0.2% yield of monocyclic aromatic hydrocarbon with 16.1 ± 0.3% yield of benzyl methyl ether was obtained by treating benzyl phenyl ether with an aqueous solution with 0.2 molar fraction of methanol, under 17.7 MPa carbon dioxi...
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