37443-42-8Relevant articles and documents
Palladium-catalyzed asymmetric hydrogenation of furan carboxylic acids
Maris, Mihaela,Huck, Wolf-Ruediger,Mallat, Tamas,Baiker, Alfons
, p. 52 - 58 (2003)
Enantioselective hydrogenation of aromatic and heteroaromatic compounds is the field where chirally modified metal hydrogenation catalysts have the biggest potential compared to homogeneous chiral transition metal complexes. Here we report the hydrogenation of furan and benzofuran carboxylic acids over a cinchonidine-modified 5 wt% Pd/Al2O3 catalyst. (S)-Tetrahydrofuran-2-carboxylic acid was synthesized in 4 h at rt and 30 bar with 95% yield and 32% ee. The ee was lower in the hydrogenation of methylfuran carboxylic acids but up to 100% de was achieved. In the slow hydrogenation of benzofuran-2-carboxylic acid, the ee went up to 50% at 29% yield. The potential application of the method is limited by the competing hydrogenation of the quinoline rings of cinchonidine in the latter reaction, necessitating the feeding of small amounts of cinchonidine during reaction. Still, this simple method using an easily available chiral modifier and catalyst affords the highest rate and ee reported so far in the catalytic asymmetric hydrogenation of furan and benzofuran carboxylic acids, and it may be an attractive route in combination with optical resolution. We assume that the reaction mechanism is analogous to that described for α,β-unsaturated carboxylic acids over the same catalyst, involving a 1:2-type interaction between the cinchonidine and the acid dimer.
Preparation method of tetrahydrofuranacetic acid and ester compounds thereof
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Paragraph 0018; 0022-0023; 0028, (2021/05/12)
The invention provides a preparation method of tetrahydrofuranacetic acid and ester compounds thereof. The preparation method comprises the following steps: in a proper solvent, in a reducing atmosphere and under the action of a hydrogenation catalyst, carrying out a reduction reaction on furanacetic acid and ester compounds thereof under the conditions that a pressure is 0.1-10MPa and a temperature is 30-250 DEG C for 0.1-72 hours, separating out the catalyst, and distilling out the solvent to obtain the target products, namely tetrahydrofuranacetic acid and the ester compounds thereof. Under relatively mild and environment-friendly conditions, efficient conversion of bio-based furanacetic acid and esters thereof is achieved, industrial production of the reaction is facilitated, platform molecules can be converted into various important intermediates or terminal products through chemical catalysis upgrading to replace existing petrochemical products, dependence on fossil resources is reduced, and the application range of biomass is expanded.
Hydrogenolysis of tetrahydrofuran-2-carboxylic acid over tungsten-modified rhodium catalyst
Asano, Takehiro,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi
, (2020/07/04)
Catalysts for reduction of tetrahydrofuran-2-carboxylic acid (THFCA), which can be synthesized from furfural via oxidation and hydrogenation, were explored among the combinations of noble metal and reducible metal oxide supported on SiO2. Rh-WOx/SiO2 catalysts showed activity in C-O hydrogenolysis at 2-position of THFCA (to δ-valerolactone and 5-hydroxyvaleric acid) and higher yield ratio of these C-O hydrogenolysis products to carboxylic acid hydrogenation products than other bimetallic catalysts. The activity of Rh-WOx/SiO2 catalysts was highest at W/Rh = 0.25 mol/mol. XRD, TPR, CO adsorption and XAFS characterizations showed that the Rh-WOx/SiO2 (W/Rh = 0.25) catalyst contained Rh metal particles with surface modification with isolated W2+ oxide species. The mechanism that hydride-like species formed on Rh atom attacks the C atom at the α-position (2-position) of adsorbed carboxylate on W atom is proposed based on the similar kinetics and similar catalyst structure to Rh-MOx/SiO2 (M = Re, Mo) which is known to be active in THFA hydrogenolysis to 1,5-pentanediol.
Selective hydrogenolysis of 2-furancarboxylic acid to 5-hydroxyvaleric acid derivatives over supported platinum catalysts
Asano, Takehiro,Takagi, Hiroshi,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi
supporting information, p. 6133 - 6145 (2019/11/20)
The conversion of 2-furancarboxylic acid (FCA), which is produced by oxidation of furfural, to 5-hydroxyvaleric acid (5-HVA) and its ester/lactone derivatives with H2 was investigated. Monometallic Pt catalysts were effective, and other noble metals were not effective due to the formation of ring-hydrogenation products. Supports and solvents had a small effect on the performance; however, Pt/Al2O3 was the best catalyst and short chain alcohols such as methanol were better solvents. The optimum reaction temperature was about 373 K, and at higher temperature the catalyst was drastically deactivated by deposition of organic materials on the catalyst. The highest yield of target products (5-HVA, δ-valerolactone (DVL), and methyl 5-hydroxyvalerate) was 62%, mainly obtained as methyl 5-hydroxyvalerate (55% yield). The byproducts were mainly ring-hydrogenation compounds (tetrahydrofuran-2-carboxylic acid and its ester) and undetected ones (loss of carbon balance). The catalyst was gradually deactivated during reuses even at a reaction temperature of 373 K; however, the catalytic activity was recovered by calcination at 573 K. The reactions of various related substrates were carried out, and it was found that the O-C bond in the O-CC structure (1,2,3-position of the furan ring) is dissociated before CC hydrogenation while the presence and position of the carboxyl group (or methoxy carbonyl group) much affect the reactivity.
Molecular features of the prazosin molecule required for activation of Transport-P
da Silva, Joaquim Fernando Mendes,Walters, Marcus,Al-Damluji, Saad,Ganellin, C. Robin
, p. 7254 - 7263 (2008/12/23)
Closely related structural analogues of prazosin have been synthesised and tested for inhibition and activation of Transport-P in order to identify the structural features of the prazosin molecule that appear to be necessary for activation of Transport-P. So far, all the compounds tested are less active than prazosin. It is shown that the structure of prazosin appears to be very specific for the activation. Only quinazolines have been found to activate, and the presence of the 6,7-dimethoxy and 4-amino groups appears to be critically important.
NAPHTHALENONE COMPOUNDS EXHIBITING PROLYL HYDROXYLASE INHIBITORY ACTIVITY, COMPOSITIONS, AND USES THEREOF
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Page/Page column 189-190, (2008/12/06)
Compounds of Formula (I) and Formula (II) are useful as inhibitors of HIF prolyl hydroxylases. Compounds of Formula(I) and Formula (II) have the following structures, where the definitions of the variables are provided herein.
Asymmetric hydrolysis of 2-hydroxy-carboxylic esters using recombinant Escherichia coli
Nakagawa, Atsushi,Kato, Ko,Shinmyo, Atsuhiko,Suzuki, Toshio
, p. 2394 - 2398 (2008/03/13)
Optically active 2-hydroxy-carboxylates are important compounds for their use as intermediates in the synthesis of pharmaceuticals and stereoblock polymers. Enterobacter sp. DS-S-75 and the recombinant Escherichia coli harbouring the 4-chloro-3-hydroxybutyrate (CHB) hydrolase gene from the strain DS-S-75 showed asymmetric hydrolytic activity towards 2-hydroxy-carboxylates, as well as towards CHB. It was discussed that the hydroxyl group in the substrate was particularly important for the asymmetric hydrolytic activity of the CHB hydrolase, and as such, it was re-designated to EnHCH (hydroxy-carboxylic ester hydrolase derived from Enterobacter sp.). Using the recombinant cell, both the reaction rate and the concentration of the substrates were significantly improved upon when compared to that of DS-S-75. Optically active 2-hydroxy-carboxylates could be synthesized on a practical basis for industrial production in this report.
PREPARATION OF ALFUZOSIN
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Page/Page column 6, (2008/06/13)
A process for preparing alfuzosin or a salt thereof, which minimizes the concentration of an N1-(4-amino-6,7-dimethoxyquinazolin-2-yl)-N1-methyl-N 2-(4-amino-6,7-dimethoxyquinazolin-2-yl)-propane-1,3-diamine impurity in the product.
AN IMPROVED AND INDUSTRIAL PROCESS FOR THE PREPARATION OF ALFUZOSIN HYDROCHLORIDE AND ITS NOVEL POLYMORPHS
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Page/Page column 11, (2008/06/13)
An improved and industrial process for the preparation of Alfuzosin Hydrochloride and its novel polymorphs (Formula (I)).
Bulky diarylammonium arenesulfonates as mild and extremely active dehydrative ester condensation catalysts
Sakakura, Akira,Nakagawa, Shoko,Ishihara, Kazuaki
, p. 422 - 433 (2007/10/03)
More environmentally benign alternatives to current chemical processes, especially large-scale, fundamental reactions like ester condensations, are highly desirable for many reactions. Bulky diarylammonium pentafluorobenzenesulfonates and tosylates serve as extremely active dehydration catalysts for the ester condensation reaction of carboxylic acids with equimolar amounts of sterically demanding alcohols and acid-sensitive alcohols. Typically, the esterification reaction is performed in heptane by heating at 80°C in the presence of 1 mol% of the catalyst without removing water. Esterification with primary alcohols proceeds without solvents even at room temperature. Furthermore, 4-(N-mesitylamino)polystyrene resin-bound pentafluorobenzenesulfonate can be recycled more than 10 times without a loss of activity.
